yacht keel type

Practical Boat Owner

• Digital edition

Keel types and how they affect performance

• Peter Poland
• June 19, 2023

Peter Poland looks at the history of keel design and how the different types affect performance

The Twister is a well-proven example of a generation of production yachts with ‘cutaway’ full keels and keel-hung rudders. Credit: Graham Snook/Yachting Monthly

Having been a boatbuilder for around 30 years until the very early ‘noughties’, I’ve already witnessed – and even taken part in – a lot of changes in the world of yacht design and building.

Yacht design originally evolved as traditional workboats developed into leisure craft.

In his History of Yachting , Douglas Phillips-Birt writes that the Dutch, who gave the name ‘yacht’ to the world, were probably the first to use commercial craft for pleasure in the 16th century.

They created the first yacht harbour in Amsterdam in the 17th century.

When the schooner America visited the UK in 1851 and raced around the Isle of Wight, this led to the America’s Cup and the resulting merry-go-round of race-yacht design that continues to this day.

The Jeanneau Sun Odyssey 35 offers three different fin keel configurations with different draughts plus a lifting keel version with a centreplate housed in a shallow winged keel stub. Credit: David Harding

The creation of what is now the Royal Yachting Association ( RYA ) in 1875 led to the introduction of handicap rules, establishing the sport in Britain.

These rating rules – and their numerous successors down the ages – have helped determine the evolution of yacht design and keel shapes.

Many early yachts were closely based on workboats, commercial cargo carriers or even privateers and naval vessels.

Initially, the ballast was carried in a long keel and the bilges .

New racing rules of the day taught designers to seek and tweak performance-enhancing features.

Maybe racing did not always improve the breed, but it certainly kept it moving ahead.

Artwork inspired by Ted Brewer’s illustration of keel types (excluding centreplate or lifting keels)

The late, great designer David Thomas believed that fishing boats, pilot cutters and oyster smacks had a large influence on the sport of sailing.

Each type of workboat was built to fulfil a specific purpose. And many had to be sailed short-handed while carrying heavy cargoes.

So they needed to combine form and function, sail well and be able to cope with heavy weather.

Proof of the versatility of working boat designs was provided by Peter Pye and his wife, Anne.

They bought a 30ft Polperro gaff-rigged fishing boat (built by Ferris of Looe in 1896) for £25 in the 1930s.

Having converted her to a sea-going cutter, and renamed her Moonraker of Fowey , they sailed the world for 20 years.

It proves how the simplest working boat design can cross oceans and fulfil dreams.

Racing influence on keel types and design

Most early yacht designs were schooners, but during the latter half of the 19th century the gaff cutter rig started to dominate the scene.

Many notable yachts were built at that time and the most important racing design was probably the yawl Jullanar (1875).

Designed and built by the agricultural engineer EH Bentall, she had, in his own words, “the longest waterline, the smallest frictional surface, and the shortest keel”.

She proved to be extremely fast and in her first season won every race she entered. Jullanar became the forerunner of such famous designs as GL Watson’s Thistle (1887), Britannia (1893), and Valkyrie II and Valkyrie III , both of which challenged for the America’s Cup during the 1890s.

Compare the She 36’s graceful overhangs with the vertical stems and sterns of most modern cruiser/racers

In the USA, Nat Herreshoff experimented with hull forms for racing yachts and produced the ground-breaking Gloriana in 1890.

She was a small boat for the times, with a waterline length of 46ft. Her hull form was very different to anything yet seen in the USA.

With long overhangs at bow and stern, her forefoot was so cut away that the entry at the bow produced a near-straight line from the stem to the keel.

It was a revolutionary design, and nothing at the time could touch her on the racecourse.

Many French models, such as this Beneteau, have opted for substantial pivoting keels. Credit: Peter Poland

Herreshoff wrote: “Above the waterline everything on Gloriana was pared down in size and weight… and every ounce of this saving in weight was put into the outside lead.”

Early English rating rules produced the ‘plank-on-edge’ yacht, where the beam became narrower and the draught got deeper.

New rating rules were then adopted to discourage this extreme type and eventually the Universal Rule was introduced in the USA and the International Rule – which produced the International Metre Classes – took over in Europe.

Yet again, racing rules proved to be a major influence on design development.

By the start of the 20th century the big, long-keeled racing yachts like the J Class attracted a lot of public attention, but after World War II everything changed. Yachts built to the Universal Rule fell from favour.

The age of the racing dinghy arrived and the ocean racer became the performance yacht of the future.

To new extremes

A 300-mile race from New York to Marblehead saw the start of offshore racing and the first Bermuda race was run in 1906.

The British were slower to compete offshore, but in 1925 seven yachts took up the challenge to race round the Fastnet Rock, starting from the Isle of Wight and finishing at Plymouth.

EG Martin’s French gaff-rigged pilot cutter Jolie Brise won the race and the Ocean Racing Club was formed.

In 1931 this became the Royal Ocean Racing Club (RORC), which remains the governing body of offshore racing in Britain.

The ‘cutaway’ modified full keel was famously used by Olin Stevens on his mighty Dorade. Credit: Christopher Ison/Alamy

The early competitors in RORC races were long-keeled cruising boats, many of them gaff rigged and designed for comfort and speed.

But everything changed in 1931 when the young American Olin Stephens designed and then sailed his family’s 52ft yawl Dorade across the Atlantic to compete in that year’s Fastnet race.

She won with ease. Then she did it again in 1933, having first won the Transatlantic ‘feeder’ race.

At 52ft LOA, with sharp ends and 10ft 3in beam, some said Dorade looked like an overgrown yawl rigged 6-metre. But her triple-spreader main mast was revolutionary. As were her cutaway forefoot, lightweight construction, deep ballast and 7ft 7in draught.

Dorade took the long keel format to new extremes.

In the USA, the Cruising Club of America (CCA), founded in 1922, played much the same role as the RORC did in Britain.

It introduced its own rating rule which influenced the evolution of yacht design in the USA.

The Elan 333. Both the deep (1.9m) and shallow (1.5m) draught models feature an elegantly faired bulb keel and spade rudder. Credit: Peter Poland

Beam was treated more leniently under the CCA rule, so wider American designs later offered more space for accommodation and a bit more inherent form stability than RORC-rule inspired yachts.

Many famous designers of long-keel racing yachts at this time developed their skills at the yachtbuilding firms they ran, such as William Fife II (1821–1902), his son William III (1857–1944), Charles E Nicholson (1868–1954) of Camper & Nicholsons and Nat Herreshoff of Bristol, Rhode Island.

Around the same time several British yacht designers made their names, including George L Watson (1851–1904) who set up one of the earliest Design Offices and Alfred Mylne (1872–1951), who designed several successful International Metre Class yachts.

Norwegian designers Colin Archer (1832–1921) and Johan Anker (1871–1940) also joined the party.

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In 1873 Archer designed the first long keel Norwegian yacht, but his real interest was work boats – pilot boats, fishing craft, and sailing lifeboats – some of which were later converted into cruising yachts.

Erling Tambs’s Teddy was a classic Colin Archer long keel canoe-stern design in which he wandered the globe with his young wife and family.

He proved the seaworthiness of Archer’s yachts, as well as their speed, by winning the 1932 Trans-Tasman yacht race.

Fellow Norwegian Johan Anker – a one-time pupil of Nat Herreshoff – became equally famous, thanks to his Dragon-class design that still races today.

As a new generation of designers arrived on the scene in the 1930s, hull tank testing became more sophisticated.

Long keel designs became as much a science as an art.

The leader of this new wave of designers, Olin J Stephens, had been a junior assistant to Starling Burgess who designed race-winning J Class yachts, including the iconic Ranger .

Tank testing was then in its infancy but the USA was ahead of the game and Stephens stored away everything that he learned. He enjoyed a head start over his contemporaries.

Keel types: Fin keels

Between the 1930s and the 1980s more fin keel designs began to arrive on the scene and his firm Sparkman & Stephens produced many of the world’s top ocean racers.

He also designed America’s Cup 12-Metres that defended the cup up to 1983 until Ben Lexcen’s winged keel shook the sailing world.

Many S&S fin keel and skeg production boats – such as the Swan 36 (1967), 37, 40, 43, 48, 53 and 65, She 31 (1969) and 36 and S&S 34 (1968) – still win yacht races and are much sought after as classics.

The S&S 34 has several circumnavigations to its name. Stephens, of course, had his rivals.

Among these was the Englishman Jack Laurent Giles, whose light displacement race-winner Myth of Malham had one of the shortest ‘long keels’ of all time.

(L-R) A Sigma 38 designed by David Thomas and Gulvain (1949) by Jack Giles as a development of his Fastnet-winning Myth of Malham have very different keel types. Credit: Peter Poland

The Dutchman EG Van de Stadt designed the Pioneer 9 (1959) which was one of the first GRP fin keel and spade rudder racers.

Towards the end of his career, Olin Stephens also came up against Dick Carter, Doug Peterson, German Frers and the Kiwis Ron Holland and Bruce Farr.

The development of new shaped keels went hand in hand with this rapid evolution in yacht design.

The full keel, as still found on motor-sailers such as the Fisher range, gave way to the ‘cutaway’ modified full keel as famously used by Olin Stephens on his mighty Dorade , designed back in the late 1920s.

She still wins ‘classic’ yacht races in the USA. American designer Ted Brewer wrote in ‘ GoodOldBoat ’ that Dorade’s offshore racing successes proved that the full keel is not essential for seaworthiness.

The Nicholson 32’s modified ‘cutaway’ long keel results in excellent performance and handling. Credit: Genevieve Leaper

As a result of its improved performance and handling, the modified ‘cutaway’ long keel caught on quickly and became the standard for around 35 years.

This keel type is found on numerous popular designs such as the Nicholson 32 , 26 and 36, Twister 28 and many Nordic Folkboat derivations.

The modified full keel format had a cutaway profile, giving good handling and directional stability while having less wetted surface than the full keel designs.

These yachts can perform well in all conditions and have a comfortable motion.

Even though they are generally of heavier displacement than fin keelers, they are not much slower in light airs , despite their added wetted surface area.

Their main drawback is a wide turning circle ahead and reluctance to steer astern when under motor.

Keel types: Increased stability

The modified full keel was subsequently cut away more and more for bluewater and inshore racers in an attempt to reduce wetted area until, finally, some designers took it to extremes.

As a result, much-reduced directional stability produced craft that were difficult to steer in breezy conditions, broaching regularly.

Whereupon the fin keel and skeg-hung rudder took over, reinstating increased directional stability, improving windward ability, reducing drag and restoring – when under power – control astern and on slow turns.

This fin and skeg format was later followed by the NACA sectioned fin keel with a separate spade rudder .

Soon, many performance cruisers followed this race-boat trend.

The Hanse 430 has a spade rudder and bulbed keel (draught 2.16m or 1.79m shoal draught. Credit: Peter Poland

Many builders now also offer shoal draught fin keel options and shallower twin rudders.

Some, such as Hanse, incorporate L- or even T-shaped bulbs on some Hanses and Dehlers at the base of finely shaped cast iron fins.

A new international competition had encouraged the initial development of modern fin keel yacht designs.

The revamped One Ton Cup was launched in 1965 for yachts on fixed handicap ratings (typically around 37ft long).

This spawned later fixed-rating championships for Quarter Tonners (around 24ft), Half Tonners (around 30 ft), Three-Quarter Tonners (around 33ft), and finally Mini-Tonners (around 21ft).

All these yachts were eventually handicapped under the International Offshore Rule (IOR) that replaced the old RORC and CCA rules.

The revamped One Ton Cup helped encourage the developed of modern fin keel designs. Credit: Getty

Countless production fin keel cruisers designed and built in the 1970’s to 1990’s boom years were loosely based on successful IOR racers that shone in the ‘Ton Cup’ classes.

The IOR handicap system’s major drawback was its Centre of Gravity Factor (CGF) that discouraged stiff yachts.

Once the international IRC rule replaced the IOR, more thought was given to increasing stability by putting extra weight in a bulb at the base of the keel.

GRP production boats followed suit. The keel foil’s chord needed to be wide enough to give good lateral resistance (to stop leeway), yet not be so wide as to add unnecessary drag.

Exaggeratedly thin foils are not suited to cruising yachts because they can be tricky upwind.

Tracking is not their forte and they can stall out. A bonus was an easier ride downwind thanks to wider sterns.

Keel Types: Lead or iron?

And then there is lead. Almost every production cruiser has a cast iron keel for one simple reason; it is much cheaper than lead. But it’s not as good.

Not only does it rust; it is ‘bigger’ for the same given weight. A cubic metre of iron weighs around 7,000kg, while the same cubic metre of lead weighs around 11,300kg.

An iron keel displaces far more water (so has more drag) than the same lead weight. We had always put iron keels under our Hunters – as did our competitors.

But when we came to build the Van de Stadt HB31 cruiser-racer, designer Cees van Tongeren said “No. We use lead.” “Why?” I asked. Cees replied: “If we use iron, the keel displaces more, so the boat sails worse.”

Rustler 36 long keel’s cutaway forefoot delivers responsiveness and manoeuvrability – a reason the design is so popular in the Golden Globe Race. Credit: Beniot Stichelbaut/GGR/PPL

Which explains why top-flight race boats have lead keels – or at the very least composite keels with a lead bulb or base bolted to an iron upper foil, thus lowering the centre of gravity (CG).

Some modern production cruiser-racers offer high-performance lead or lead/iron composite keels – but at a price.

Many Danish X-Yacht and Elan race-boat models, for example, have a lead bulb on the base of an iron NACA section fin.

Rob Humphreys, current designer of the popular Elan and Oyster ranges, said: “The T-keel is good if you have sufficient draught available. If not, the fin element has too short a span to do its job. This is because the T-bulb doesn’t contribute as usefully to side force as a ‘filleted L-bulb.’

“I developed and tested this shape (a blended-in projection off the back of the main fin) for the maxi race boat Rothmans in 1988/9, and have since used it on the Oysters and Elan Impressions. The ‘filleted’ keel we tested for Rothmans had slightly more drag dead downwind (more wetted area) but was significantly better when any side-force occurred; and side-force goes hand-in-hand with heel angle – which is most of the time! When the model spec allows for reasonable draught, the keel option with the lowest centre of gravity will invariably be a T-keel, with a longer bulb giving the greatest scope for a slender ballast package. An L-keel is a compromise and doesn’t suffer from the risk of snagging lines, mooring warps, and nets. [many modern production cruisers have 100% cast iron L- or T-shaped keels]. A lead bulb is preferable to a cast iron keel in terms of volume and density, but it costs more. However, a lead T-keel in a production environment will almost certainly use a cast iron or SG Iron fin, which may rust.”

The Mystery 35, designed by Stephen Jones and built by Cornish Crabbers, has a lead fin keel. Photo: Michael Austen/Alamy

Rustler Yachts also uses lead instead of iron for their keels.

The Rustler 36 long keel (designed by Holman and Pye and winner of the 2018 Golden Globe Race) has a cutaway forefoot to improve responsiveness and manoeuvrability.

The long keel creates more drag but, as with the Rustler 24, the cutaway forefoot makes the 36 more nimble than a full long keel boat, which are more difficult to manoeuvre in reverse under power.

The rest of Rustler’s offshore range – the Rustler 37, 42, 44 and 57 – designed by Stephen Jones – have lead fin keels.

As does his Mystery 35 built by Cornish Crabbers.

These offer an excellent combination of directional stability, performance and lateral stability. The yachts track well, are comfortable in choppy seas, and have good manoeuvrability, all without the flightiness of shorter chord fin keels found on many production family cruisers.

A digital future

Influential designer David Thomas said: “When I started designing, I integrated sharp leading edges to the keel; until someone told me a radius was better. Then we were all taught that an elliptical shape was better still. With the advent of computers, designers could better visualise the end-product; and clever ‘faring programs’ speeded this up.”

So where next? A combination of lighter and stronger materials, rapidly developing computer programs, a desire for maximum interior volume and low costs has led us to today’s production yacht.

Twin rudders improve the handling of broad-sterned yachts when heeled.

The IRC rating rule permits low CG keels, wider beam and near-vertical bows and sterns.

And designers now have an array of new computer tools at their disposal. But maybe there’s still that element of black magic?

As David Thomas so succinctly said: “You can design a yacht 95% right, but the last 5% can be down to luck.”

Keel types : the pros and cons

Full length keel

The Fisher 31 and many motor-sailers have long keels. Credit: Peter Poland

Pros: Directional stability. Heavy displacement leading to comfort at sea.

Cons: Poor windward performance. Large wetted surface leads to drag. When under power at low speeds, the turning circle is wide unless fitted with thrusters. The same applies to manoeuvring astern.

Cutaway modified long keel form with keel-hung rudder

Pros: Reduced wetted surface area leading to increased boat speed. Better windward performance and handling than full length keel. Rudder on the aft end of the keel improves self-steering ability on some designs.

Cons: Under engine, this keel form has a large turning circle ahead and poor control astern. Since the rudder is not ‘balanced’, the helm on some designs can feel quite heavy.

Fin keel with skeg-hung rudder

The skeg gives protection to the rudder. Credit: Graham Snook/Yachting Monthly

Pros: The further reduction in wetted surface area leads to more boat speed. Directional stability and close-windedness are also improved. If full depth, the skeg can protect the rudder against collision damage.

Cons: When combined with a narrow stern, this keel format can induce rolling when sailing dead downwind in heavy winds.

Fin keel with separate spade rudder

Fin keel with spade: Low wetted surface and aerofoil shapes enhance performance. Credit: Graham Snook/Yachting Monthly

Pros: The fin and spade rudder mix reduces wetted surface and gives a more sensitive helm – especially if the blade has ‘balance’ incorporated in its leading edge. Handling under power in astern is precise and the turning circle is small.

Cons: The rudder is fully exposed to collisions. There are no fittings connecting the rudder to a keel or skeg, so the rudder stock and bearings need to be very robust.

Shallow stub keel with internal centreplate.

Pros: When lowered, the plate gives good windward performance. The plate can act as an echo sounder in protected shallow water. There is normally no internal centreplate box to disrupt accommodation. With the plate raised, off-wind performance is good.

Cons: The plate lifting wire needs regular inspection and occasional replacement. Windward performance with the plate raised is poor.

Lifting or swing keel

Boats with lifting keels tend to surf earlier downwind. Credit: Graham Snook/Yachting Monthly

Pros: Shallowest draught so more cruising options; can also be moored on cheaper moorings. Surfs early downwind. Small wetted surface so can be fast.

Cons: Reduced living space due to internal keel box. With a raised keel, poor directional control. Susceptible to hull damage if grounding on hard material.

Twin or bilge keel

Bilge- or twin-keelers can take the ground on the level. Credit: Graham Snook/Yachting Monthly

Pros: Can take the ground in a level position. Modern twin-keel designs with around 15º splay, around 2º toe-in and bulbed bases perform well upwind. Good directional stability due to the fins. Modern twin keels with bulbed bases lower the centre of gravity.

Cons: Older designs do not point upwind well. Slapping sound under windward keel when at a steep angle of heel on older designs. Antifouling between the keels can be tricky. Can be more expensive than fin keels.

Wing keel: A low centre of gravity gives a good righting moment. Credit: Graham Snook/Yachting Monthly

Pros: Low centre of gravity means good righting moment. Shallow draught. Sharper windward performance.

Cons: Larger surface area means it is more likely to pick up fishing gear, like lobster pots. Difficult to move once it is grounded. And difficult to scrub keel base when dried out alongside a wall.

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Sailboat Keel Types: A Complete Guide

A keel is a very important part of a sailboat, crucial to its stability and ability to sail upwind. This article will discuss the fundamentals of all keels down to the details of the best keel for your boat. We will answer questions including what it does, what it's made of, and even some problems that a keel can cause. By the end of this article, you will be an expert on all things keels!

Table of contents

What Is a Keel?

A keel is the robust underwater centerline of a boat, and often extends into a long, hydrodynamically shaped blade.. It can vary in size and shape depending on the make and model of the boat. But, generally, it will look very much like a fin. If you imagine the fin on the underside of a surfboard you will have a pretty good idea of what it looks like under the boat.

It is crucial to helping with steering and control. The word keel itself comes from Norse and Dutch roots. The word simply means a structural component of the boat. You may have heard the term keel-haul, where pirates would drag someone underneath the boat across its keel. This is pretty barbaric, but it shows just how long a keel has been an important part of the boat. From Vikings to pirates to modern sailboats it has always remained an important part of a sailboat.

What is a keel made of?

A keel will typically be made of whatever the rest of the hull is made of. If the boat is wooden, it will most likely have a wooden keel. If the boat is metal, the keel will be metal, and so on. Sometimes, particularly on fiberglass boats, the core of a keel will be reinforced with lead or a similar ballast while the outside is covered with fiberglass.

The keel needs to be strong enough to withstand a lot of pressure and strain. Traditionally Viking sailing boats would have a wooden keel with some metal plating on it. Casting metal was tedious so putting it on your boat was seen as a waste. Traditional wooden sailing boats, like you would imagine pirates sailing, would also have a wooden keel. It would be made from thick hardwood like oak and could also be metal plated.

Since it is used to control the direction it must brunt the force of the change of direction. If you imagine a boat turning sharply, there will be a lot of pressure on the side that is on the outside of the turn. The hull of your boat will stand up to this pressure easily, as it is very large and very strong. The keel must be strong enough to withstand this too. The keel also can drag on the ocean floor or the boat ramp as the boat is lowered into the water. For this reason, it needs to be strong enough to hold up to the weight and pressure of the boat too. If it were made of plastic it would break every time you brought the boat in and out of the water.

What does a keel do?

The keel is there primarily for stability and guidance. The keel provides all sorts of benefits to the boat. It improves the righting moment and controls the boat’s sideways movement. The keel will also typically hold the boat’s ballast. The ballast keeps the boat weighed down and helps prevent capsizing. The ballast is typically made of lead, sand, or water.

Keels can be fixed or moveable. Some keels can be removed completely or may just retract slightly so they aren’t damaged when the boat enters or exits the water. When a boat leans to one side, because it is turning or there is strong wind/waves, the keel provides the righting moment that keeps the boat from flipping. On larger boats, it is designed to be so heavy that ig will be able to recover a boat from almost any angle of heel. Without a keel, your boat may tip too far or roll completely. On bigger ships, this can be disastrous. In its ability to prevent this alone, the keel is one of the most important parts of the ship.

Does my sailboat need a keel?

Yes, you do need a keel. Pretty much all sailboats have a keel, with exceptions for multi-hulled and/or smaller boats.  

In the case of catamarans, the very design principles that lead to the dual-hull design render the keel obsolete. The stability introduced by the outrigged, dual-hulls replaces the necessary righting moment from the keel. Because almost all the structure of a catamaran is between the two hulls, unlike a monohull which builds out from and around its centerline, there is not a lot of weight pressing out to flip the boat. Related to this, since most catamarans have the length of their hulls pressing into the water, the steering force normally placed on a keel is distributed across the length of the two hulls, which additionally will carry their own ballast.

On smaller dinghies, a small swinging centerboard or daggerboard will suffice to play the role of a keel. The centerboards can be big enough to keep the boat flowing nicely through the water without the need for a large keel. Additionally, it is not a disaster for a small sailing or racing dinghy to capsize, as they are designed to do so and recover rather easily, so the ballast from the keel is also not terribly necessary. 

If you have a motorboat you wouldn’t need a keel, unless it is a very large container ship or military vessel. The reason being that they are outboard propelled. The leg provides enough stability on its own. This is only the case with full plane powerboats. Displacement (even semi-displacement) craft will still need a keel of sorts for stability purposes.

What are some downsides to having a longer keel?

If you have a long keel that doesn’t retract or detach, you may have some problems coming in or out of the water. The keel extends far below the bottom of the boat, so if you are bringing your boat up or down a boat ramp you may find that it scrapes on the bottom. If you are not careful, you may damage the keel rather badly.

Since the keel is made of metal, wood, or fiberglass it can bear the brunt of the weight quite well. If you are putting your boat in the water and cannot retract the keel, it is a good idea to go as far into the water as possible before taking your boat off its trailer. The deeper you are in the water when the boat is released the better.

Are there any nautical traditions about the keel of the boat?

The keel is interestingly very important when it comes to boat or shipbuilding.

Traditionally, the keel is one of the first parts of the ship to be made, as the rest of the ship must sometimes be built around it. This tradition is called “laying the keel,” and is a momentous occasion. It is essentially the boat’s birthday. The boat’s age is dated from this moment, and there is also typically a celebration of sorts. This goes back to the days of seafaring exploration. The only day more important in a boat’s life is the day it is finally launched.

Can other types of boats have keels?

Yes! Many other types of boats have keels, not just sailboats. A good example would be a big shipping trawler. These trawlers are very large and need all the help they can get to stay balanced. Because of this, they often have what’s called a bar keel. This is a large rectangular piece of metal that runs along the bottom of the boat’s hull. It is very thick and heavy. The idea is that it gives the boat some more directional control when steering.

Furthermore, it helps keep the trawler balanced when out at sea in rough conditions. The extra weight keeps the boat’s center of gravity as low as possible. This makes tipping the boat almost impossible. It does slow it down a bit, but that is a small price to pay for increased safety.

Huge cargo ships also have a keel, though it is different from a bar. Their keel is known as a plate keel. It is essentially another layer of the boat under the hull. Its only purpose is added weight and protection. A plate keel runs along the centreline of the bottom plate of the ship so the weight is all concentrated in the lowest place possible. This kind of keel works similarly to how the spine of a person does. It keeps your back strong and as straight as possible.

How important is it to keep my keel clean?

It is very important to keep your keel clean, just as it is important to keep the rest of your hull clean.

For any boat kept on the water rather than hauled out every day, there is always the need to clean the hulls and keels of any barnacles and other sea growth. Barnacles not only affect your performance, but can, in the long run, greatly increase your maintenance costs if not regularly addressed. 

To do so, you have to do what is known as scraping. Scraping is the process of physically scraping off all the barnacles and other sea life that has attached itself to the underside of your boat. Many marinas offer this service, but you can do it on your own with a basic plastic paint scraper and a wetsuit. When you do this, it is key to get all the way down to the bottom of the keel and all across the hull. If you don’t scrape it off, it can start to erode your boat away over time. It can also slow you down.The barnacles and other marine life create a very rough bottom. This creates more friction and will reduce your speed more and more the worse it gets. 

It is important to check with your port authority before you start scraping. Scraping is not allowed in some places as you may introduce invasive species to the area. It depends where you have been more than where you are. If you sailed from New York to Chicago, you will be fine. If you sailed from Cuba to New York, probably not so much.

How to maintain a sailboat keel

As mentioned above, it is important to scrape your keel from time to time. While racing boats will actually do this before every day at an event, it is at least a good idea for you to do this a couple of times a season. A great time to do this is when you plan on applying that season’s bottom paint, though anytime you plan to go on your boat is a good excuse to maintain!

You may want to cut off any of the kelp and seaweed that wraps itself around the keel. This is more likely to happen if you have a fin keel. If you do find that there is a lot of kelp and seaweed wrapped around it, you will want to buy yourself a kelp cutter. Unfortunately, the only way to cut the kelp off without taking the boat out of the water is to dive in and do it yourself. It is a good idea to do this in shallow-ish water with the proper flags displayed to inform other boaters that there is someone in the water. Swimming around under your boat, even when it isn’t moving, can be dangerous.

What do I do if my keel breaks at sea?

It is very rare for keels to just break off. It is even rarer at sea. After all, what is going to break it off? The only way a keel will break off ordinarily is if you run aground.

If you should accidentally make your way into shallow waters and break your keel off it is a good idea to set sail for home. You will manage well enough in the short term but will struggle over time. You are far more likely to capsize without the keel keeping you balanced.

If you have a detachable keel it is a good idea to keep a replacement. If one breaks off, you can just install the spare one. This isn’t the easiest thing to do at sea in rough conditions, but it is possible. Make a judgment call using your common sense whether it is worth the risk or not.

Another reason your keel might break or come loose is if the keel bolts come out. These bolts are what holds the keel in place. If you happen to have a keel held on by bolts, then doing proper maintenance is even more important. If the bolts come loose, the keel can come loose.

Since the keel is typically welded on to the boat’s hull the chances of it coming off completely are slim to none. Most often, running aground on a sandbar or anything short of an incredibly rocky bottom in heavy weather will crack off a piece or severely bend the keel, which requires a major repair. If you do notice that the keel is loose, you are better off taking it back to the marina. The bolts may not come off without using some machinery, meaning you might have to take your boat out of the water. If your keel starts to rust, you may need to speak to a professional.

What are the different keel types?

Now you know what a keel is, what it does, why it is important, and how to care for one it is time to learn about the specific types of keels. Big trawlers and cargo ships have bar or plate keels, but sailboats do not. Here are the 6 different types of keels typically found on sailboats and their purposes:

The full keel is one of the most common types of the keel that you are likely to see on a sailboat. A full keel runs from end to end of the boat lengthways. A full keel, as the name implies, runs almost the entire length of the boat. At a minimum, it must run 50% of the length of the boat. A full keel is one of the most stable keel types, which is why it is so common. Full keels are also safer should you run aground. If a boat with a full keel should come ashore, it will cut its way through the sand and eventually land on its side. Whether you are grounding your boat intentionally or not, your boat will have far better odds of surviving the ordeal with a full keel.

A fin keel is similar to a full keel, just shorter. There may be one or two fin keels along the length of the boat hull. A fin keel is defined by being less than 50% the length of the boat. The fin keel works almost entirely the same way that a shark's fin does. When you wish to turn, the keel provides the resistive force that keeps you turning. This means that it essentially acts as your tires going into a turn. Whereas a full keel is essentially just a long fin, a fin keel has very different benefits. A full keel is more stable and safer overall. A fin keel is sleeker, smaller, and most importantly makes you faster. Most racing sailboats have fin keels.

A bulbed keel is very similar to a fin keel. In fact, it is possible to make a bulb keel by shaving off part of a fin keel and attaching a bulb. Once the keel has been made substantially shorter, the bulb is fitted. The bulb is shaped similarly to how a torpedo would be on a submarine. This keel works the same as a fin keel does, offering a slightly more stability without sacrificing speed. The biggest difference between a bulb and a fin keel (besides shape and length) is where they are used. Bulb keels are most commonly used in places with very shallow waters and lots of rock/shale/coral outcrops. Somewhere like the Caribbean would be the perfect place for a bulb keel. The rounded bulb bounces off the rocks and is less likely to break off. It just isn’t going to be as quick as if you used a fin keel.

The wing keel is another alternative to your standard fin keel. Just like the bulb keel, a wing keel is an extension to the standard fin keel with an extra fitting at the bottom. A wing keel is far more streamlined than a bulbed one, at the expense of being more susceptible to breaking. A wing keel looks very similar to the tail of an airplane. It works the same way, too. The water can pass by either side of the wings, allowing you to adjust your course easily. But, a wing keel does have one major problem. If you do run aground, digging out a wing keel can be very difficult. Whereas digging out a standard fin is as simple as scraping sand away from the sides of it, a wing keel must be dug out completely. The wings act like little shovels and wedge themselves into the sand. These are generally limited to higher performance racing classes.

Centerboard Keel

A centerboard keel works similarly to a fin keel but it can retract slightly. It works by having a dagger that folds out downwards. When you are sailing, the dagger protrudes outwards and offers you all the stability and balance of a fin keel. When you are in shallow water, the dagger can be retracted upwards, essentially shortening the keel temporarily. This should be done when you are sailing in shallow waters or removing the boat from the water entirely using a boat ramp. Some centerboards work on a loose hinge. When the boat is sailing along, the dagger is out and the fin works as normal. If you should bump into something though, like some shallow rocks, the hinge would push the daggerboard back inside. This stops the keel from breaking, instead, it just moves out the way. This only works if you are only just deep enough. If you are in very shallow water you would just break the centerboard off.

Canting Keel

A canting keel also works on a hinge. Instead of working end to end, it works port to starboard. When the boat turns a corner, the canting keel swings from side to side. This allows the boat to maximize its balance and speed. Eventually, this will become the norm in racing. But at the moment it is still quite experimental. The biggest downside is that the hinge works on hydraulics, and hydraulics can fail. If they should fail at sea there is very little you can do to repair them. Once they have perfected these canting keels, they will move first into the racing classes and high performance boats, then to all new cruising boats as boatbuilders improve the technology. .

Hopefully, you now have a good idea about what a sailboat keel is,how it works, why it is so important, and, of course, all the different types. Chances are, when you buy a sailboat , the keel it has is going to be at the bottom of your list of priorities. That being said, if you are planning on sailing somewhere in particular, it is a good idea to think about what keel type you are using. Replacing them doesn’t have to be expensive, but you can go a long way to saving yourself that money either way by being prepared for your home waters!

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6 Most Popular Types of Sailboat Keels

If you’re new to sailing, you might be wondering what that wing-like object is doing attached to the bottom of your sailboat. Well, that would be called the keel and it serves some important functions so that your sailboat can… sail!

So what are the different types of sailboat keels? The most common types of sailboat keels include full-length, fin, short, wing/bulb, bilge, and centerboard keels.

There’s a lot of useful knowledge when it comes to understanding keels since they take such a considerable role in making a sailboat a sailboat.

Knowing the different types of sailboat keels can really make a difference when heading out on the water for a nice sailing session.

Quick Keel Knowledge

Having a sailboat without a keel means you don’t have a sailboat.

As a matter of fact, when a sailboat is first constructed and tipped on its side to attach the keel, or laying the keel, this is considered the “birthday” of a sailboat and thus the initial time of construction.

One of the more interesting facts about keels is they find their origins all the way back in ancient China, which allowed them to expand their naval presence all around the world.

Of the different types of keels discovered were the use of adjustable centerboards and bilge keels.

Now, a keel is an important part of a sailboat because it provides two very important functions:

• Converts the sideways force of the wind into forward motion.
• Provides ballast (i.e., keeps your sailboat from tipping).

We’ll get into these important functions of a sailboat’s keel later on. For now, let’s dive into the different types of sailboat keels!

Different Types of Sailboat Keels

There are several common setups for sailboats when it comes to keels. Even though these types of keels differ from one another, they ultimately serve the same purposes.

However, it’s important to differentiate them based on use cases and other unique characteristics.

1. Full-Length Keel

A common type of sailboat keel is a full-length keel, which uses length rather than depth to provide a sailboat with a proper amount of life and ballast.

When it comes to the location of the rudder on a sailboat with a full-length keel, it’s often attached to the aft (rear) of the keel.

There are several advantages of having a full-length keel. One is that they’re well known for keeping a straight and steady course more easily due to the length and surface area, which makes for a relatively comfortable ride.

Also, if your keel runs aground (the keel touches the sea floor), there’s less likely to be a lot of damage due to a spread of the load.

However, there are some disadvantages to a sailboat that has a full-length keel. Due to the advantage of it staying straight and steady more easily, it’s also slower to turn (tack) when the rudder is moving.

This means you’ll have a longer delay between the turn of the rudder and the turn of the sailboat. Also, sailboats with a full-length keel are a bit slower than others due to the larger surface area dragging against the water.

2. Fin Keel

Another very common type of sailboat keel is a fin keel, which you’ll most likely find on more modern sailboats.

A fin keel has less surface area touching the water when compared to a full-length keel due to it taking on the shape of a… well a fin! This fin, however, sticks out of the bottom of the boat.

Just like the full-length keel, there are some advantages to having a fin keel on your sailboat.

The most obvious one when sailing on a boat with a fin keel is the speed since the fin keel has less surface area and a better airfoil shape just like a wing on an airplane.

A fin keel also provides for a faster response when tacking, which is great if you need to turn quickly.

There are also some issues with having a sailboat with a fin keel. One is that if you have high-powered winds hitting your sails, it’s likely you’ll feel the tilt of your sailboat relatively more than with a full-length keel. This is especially true for different types of sails .

Also, since the tacking is more responsive, you’ll need to spend extra attention on the track of the sailboat as you sail along. With a fin keel, you definitely need to be on high alert at times.

3. Wing/Bulb Keel

Wing/bulb keels are another type of sailboat keel that can be found.

As the name suggests, they take the shape of a wing at the very bottom of the keel and also can have a fat bulb centered at the middle-bottom of the wing. These types of sailboat keels are more often found are longer and heavier boats.

A boat that uses a wing or bulb keel has several advantages that other boats don’t have. For one, it provides a boat with greater efficiency due to a modified water flow that benefits the forward motion of larger boats.

It’s also relatively smaller in terms of surface area and quite hydrodynamic, so there’s reduced friction between the keel and the dragging water.

Similar to the fin keel, the wing or bulb keel has disadvantages related to having to spend greater attention when at the help due to a more responsive tack as well as being susceptible to heavy tilting during relatively strong incoming winds.

4. Shoal Keel

The shoal keel is a type of sailboat keel that’s virtually the same as a fin keel, only it’s a bit more shallow.

Due to it being less deep than a fin keel, it has the advantage of being better able at maneuvering around shallow areas. However, since it does have a smaller surface area it’s much more likely to tilt easier when the wind starts to pick up.

5. Bilge Keel

Bilge keels are a special type of sailboat keel due to them coming in pairs.

When a sailboat has a bilge keel, there will be two fins that stick out at the same angle from the bottom of the hull. Think of the fins of a shark and how they stick out at an angle from the bottom of the body.

There are some nice advantages of having a bilge keel on your sailboat. For one, they allow your sailboat to traverse through shallow water without going aground.

Also, if you let the boat dry out on land, it’s very convenient to simply let your sailboat sit on the fins of the bilge keel.

Some of the disadvantages of having a bilge keel on your sailboat include being difficult to free if ever aground since they might get stuck and not being as effective in reducing sideways slippage (leeway) underwater.

They also produce a lot of drag due to having a large wetted surface, which makes it difficult to sail at greater speeds.

6. Centerboard

Centerboards are another special type of sailboat keel because they can be lowered and raised mechanically. Being able to extend or retract a sailboat’s keel means your sailboat’s less likely to run aground, which makes it a fantastic option for coastal and offshore sailing.

One of the main advantages to having a centerboard is having the ability to retract it when entering shallow water, removing the chance of running aground.

Since you can effectively increase or decrease the surface area of your keel at will, you’ll be able to reduce draft and wetted surface resulting in finer control of the lateral resistance of your keel.

However, there are a few downsides to having a centerboard compared to virtually every other type of sailboat keel. One issue is that they’re rather difficult to maintain.

Another is that they have a ballast that is closer to the core of the boat resulting in the need to increase your sailboat’s ballast displacement. All of this ends up being a headache!

Keels Move a Sailboat Forward

How a keel is able to convert the force of sideways winds to forward motion is based in the science of hydrodynamics, similar to how airplane wings work based on aerodynamics . Essentially what happens is:

• The wind hits the sails at an angle
• The wind force causes the sailboat to tip
• The keel resists the lateral part of the wind force
• Energy from the angle portion of the wind force transfers to forward motion

This explanation is pretty basic, but should hopefully provide a clear insight into how a sailboat is able to produce forward motion thanks to the keel.

Sailing Ballast

One of the most important purposes of a keel is to provide ballast for a boat. Essentially, sailing ballast is the ability to resist the lateral forces of the wind based on the weight and size of the keel. As a matter of fact, this is a major reason why step 4 in the above list is able to produce forward motion.

Now, most keels are known to be made out of cast iron, steel, lead, and even concrete due to these materials being high in density. Back in the day during “olden times”, decent keels were made out of stone and sand.

When a keel has too little ballast, a sailboat tends to tip (heel) too much during high winds. However, if the keel has too much ballast, the sailboat is at risk of capsizing. That’s why a proper amount of ballast is required for light and heavy winds.

There are multiple ways of creating ballast on a sailboat. Apart from having a high-density keel, your sailboat could have a water ballast which allows you to adjust a certain amount of water sitting in your hull.

Another way is “live ballast”, which pretty much means the excess weight on the sailboat produced by us sailors.

Positioning dense weight below the hull to produce good ballast is important, which is why keels are the perfect place to put it.

In the end, proper ballast provides stability and speed for all types of sailboats and is an essential function of a keel.

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Yachting Monthly

• Digital edition

How keel type affects performance

• Chris Beeson
• December 2, 2016

James Jermain looks at the main keel types, their typical performance and the pros and cons of each

A fin keel and spade rudder configuration gives high pointing but can be sensitive on the helm Credit: Graham Snook/YM

James Jermain has tested hundreds of yachts in his 30 years as Yachting Monthly’s chief boat tester

The performance and handling of a yacht depends on many things, but perhaps the most important single feature is the shape of the hull and the profile of the keel. Over the years hulls have become shallower and keels narrower, but for many types of sailing this progression is not necessarily progress. Of the various shapes that have evolved, each has its own advantages in different circumstances. Here is a run-down of how they may fit your sort of sailing.

FIN KEEL WITH SPADE RUDDER

A low wetted surface area and aerofoil shape means speed and agility

The most common modern option, usually combined with light but beamy hulls with high freeboard.

GENERAL AND TO WINDWARD

• Low wetted surface and good aerofoil shape means good speed, high pointing and quick tacking
• Light steering
• Best designs can slice through heavy seas in reasonable comfort
• High volume, light-weight designs can be lively and tiring in heavy weather
• Flat sections can cause slamming
• Less steady on the helm, requiring more work and concentration
• Strong tendency to round-up when hard pressed
• Generally require earlier reefing
• Can be unstable when hove to
• Quick to surf and may even plane
• Can broach easily and suddenly
• Can be directionally unstable and hard to control in heavy conditions

UNDER POWER

• Handling is precise and turns tight and quick
• Some handle almost as well astern as ahead
• Limited lateral area so susceptible to beam winds at low speeds
• An unattended helm can slam over suddenly

FIN KEEL WITH SKEG RUDDER

The skeg running aft protects the rudder and improves tracking under sail and power

Similar to above but with some key differences.

• Skeg provides better support for the rudder
• Tracking under sail or power is improved
• There is less chance of damage
• More wetted surface so potentially slower
• Objects can get stuck between rudder and skeg
• Limited balancing can make helm heavier

The mass of a long keel is often more seakindly and will carry way well.

The traditional option, usually found on pre-1970s designs.

• Good tracking
• Slow, soft, comfortable motion
• Drive powerfully through short seas but can be wet
• Carry way through tacks
• Resist rounding-up
• Heave-to well
• High wetted surface area and a poor aerofoil shape, so speed reduced, tacking slow, leeway increased and pointing ability reduced
• Long ends can cause hobby-horsing
• An unbalanced hull or rig can cause heavy helm
• Track well and very resistant to broaching
• Very stable in heavy conditions
• Reluctant to surf (a mixed blessing)
• Carry way well
• Track straight
• Heavy construction can reduce vibration and noise
• Large turning circle ahead
• Unpredictable and hard to control astern

LIFTING OR SWING KEEL

A lifting keel enables beaching, but beware of stones jamming the plate

The ultimate shallow-draught option.

• A fully retracting keel offers shallowest draught
• A well-designed lifting keel can be very efficient and fast
• Grounding on anything other than soft mud or sand can damage an unprotected hull
• Stub keels offer better protection but are less efficient and prevent level drying out, except in soft mud
• Stones and dried mud can jam the lifting plate
• Internal keel boxes reduce accommodation space
• Directional stability is poor
• Early surfing and planing
• Control can easily be lost in strong winds
• Good performance and handling with keel down
• Directional control increasingly poor as the keel is raised

TWIN OR BILGE KEEL

A bilge-keeler will dry out upright on a flat bottom

A popular shoal-draught option in Britain, less so abroad.

• Shallower draught
• Dry out upright on a flat bottom
• Good protection when grounding
• Good designs are better to windward than long keels, almost as good as fins
• Pointing and speed to windward is reduced, considerably so in older designs
• When well heeled, waves can slap under the windward keel
• Can topple over if one keel finds a hole or soft ground

Modified water flow over the wing keel foot can give the motion of a longer, heavier boat

Once popular, now largely replaced with various types of bulb.

• Reduced draught
• Low CoG means good righting moment
• Modified water flow over keel foot means greater efficiency and gives the motion of a longer, heavier boat
• More likely to pick up lobster pots, etc
• Risky drying out
• Weed and barnacle growth under wings difficult to remove

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• Mastering the Depths: The Sailboat Keel Guide

The keel of a sailboat is more than just an architectural feature; it's the foundational element that ensures stability, performance, and the directional integrity of the vessel. Acting as the backbone of the boat, it runs longitudinally along the bottom, playing a crucial role in preventing the boat from being blown sideways by the wind. But the keel is not just about stability; it's intricately linked to how a sailboat interacts with the water and wind, affecting everything from speed to maneuverability. Diving deeper into the specifics, the variety in keel designs is vast, each tailored to suit different sailing needs and environments. From the slender and deep fin keel, known for its speed and agility, to the bulb keel with its characteristic bulb at the bottom for enhanced stability, the design choices are many. There's also the wing keel, designed for shallow waters, reducing the draft without losing stability, and the full keel, which is excellent for long-distance cruising due to its exceptional directional stability. Not to forget the twin keel, which allows a sailboat to stand upright on low tides and offers remarkable stability in heavy weather conditions.

The Balancing Act: Keel Types and Sailboat Performance

The keel's influence on a sailboat's performance cannot be overstated. It's a balancing act, quite literally, where the keel's design directly impacts the boat's stability, speed, and maneuverability. The choice between a deep keel and a shallow keel, for instance, is a decision that touches upon the very nature of one's sailing. Deep keels excel in open waters, offering unmatched upwind performance, while shallow keels are better suited for navigating coastal areas and shallower bodies of water.

But how does one choose the right keel? It's a combination of understanding the specific sailing environment, the performance expectations, and personal sailing style. Whether it’s for competitive racing or leisurely cruising, the keel must align with the sailor's aspirations and the challenges of the waters they intend to navigate.

Navigating Choices: Selecting the Right Keel and Ensuring Its Care

Selecting the right keel for your sailboat involves a detailed analysis of various factors, including the type of sailing you're interested in and the conditions you expect to face. Each keel type brings its own set of advantages and challenges. The maintenance and care for sailboat keels are equally important. Regular checks, cleaning, and upkeep are essential practices that extend the longevity and preserve the performance of the keel, preventing long-term issues that could hamper your sailing experience.

Read our top notch articles on topics such as sailing, sailing tips and destinations in our Magazine .

Check out our latest sailing content:

The voyage of evolution: from simple structures to sophisticated designs.

The history of sailboat keels is a fascinating journey of evolution, showcasing human ingenuity and the relentless pursuit of better, more efficient designs. This evolution is not just about improving performance but also about adapting to the changing environmental conditions and the growing demands of the sailing community. Innovations in sailboat keel designs continue to emerge, driven by a desire to enhance efficiency, reduce environmental impact, and push the boundaries of what's possible on the water.

Charting the Future: Innovations and Trends in Sailboat Keel Design

The future of sailboat keel design is as promising as it is exciting, with new advancements focusing on optimizing performance, eco-friendliness, and adaptability to diverse sailing conditions. These innovations are not just about pushing the limits of speed and agility but also about ensuring that sailing remains a sustainable and accessible sport for generations to come.

The keel is a testament to the intricate dance between form and function, a crucial component that defines a sailboat's relationship with the sea. Understanding the various types of keels, their functions, and how they impact sailboat performance is essential for every sailor. As we look to the horizon, the continuous innovation in keel design promises a future where sailing is not only about embracing the wind and waves but doing so with an eye towards efficiency, sustainability, and harmony with the marine environment.

So what are you waiting for? Take a look at our range of charter boats and head to some of our favourite  sailing destinations.

I am ready to help you with booking a boat for your dream vacation. Contact me.

Denisa Kliner Nguyenová

Sailboat Keel Types: A Comprehensive Guide

by Emma Sullivan | Jul 25, 2023 | Sailboat Maintenance

Short Answer: Sailboat Keel Types

There are several types of sailboat keels, including full keel, fin keel, wing keel, bulb keel, and daggerboard. Each type provides different characteristics in terms of stability, maneuverability, and performance. Sailors choose the keel type based on their sailing preferences and intended usage of the boat.

Understanding Sailboat Keel Types: A Comprehensive Guide

As any avid sailor can testify, understanding the different sailboat keel types is paramount to a successful and pleasurable sailing experience. A sailboat’s keel acts as its foundation, providing stability, preventing sideways drift, and enhancing overall performance. With various keel options available in the market, it can be quite overwhelming for newcomers or even seasoned sailors to grasp the nuances of each type.

In this comprehensive guide, we aim to unravel the mystery surrounding sailboat keels. From traditional full keels to modern fin keels and everything in between, let’s embark on a journey through their characteristics, advantages, disadvantages, and their impact on sailing dynamics.

1. Full Keel:

Let’s start with the old-school favorite – the full keel. As its name suggests, this keel extends from bow to stern and offers exceptional stability due to its large surface area below the waterline. The long length also promotes tracking ability – keeping your boat moving in a straight line without much effort. Although typically found on older vessels or those designed for long-distance cruising rather than racing, full keels excel in handling heavy weather conditions and provide an overall smooth ride through choppy waters.

However, there is a trade-off when it comes to maneuverability. The deep draft can restrict access to shallower areas and make tacking (changing direction by turning into the wind) more demanding. Additionally, due to their shape and size, full keels may sacrifice some speed potential compared to their sleeker counterparts.

2. Fin Keel:

Enter modernity – the fin keel revolutionized sailing dynamics when it was introduced decades ago and remains one of today’s most popular choices among sailors seeking performance-oriented vessels. This relatively narrow (or “fin-like”) appendage protrudes deep below the hull and serves as both a counterbalance against sideways forces and a pivot point for agile maneuvers.

The fin keel’s streamlined design offers enhanced speed, better upwind capabilities, and improved responsiveness. Sailors planning to participate in racing events or seeking a thrill-seeking sailing experience often favor this type of keel. Moreover, the reduced draft allows for access to shallower waters – perfect for exploring coves or venturing closer to shore.

However, it’s essential to recognize that while fin keels excel in speed and maneuverability, stability can be compromised. A narrow base may result in more heel (tilting) when exposed to strong crosswinds, demanding careful attention from sailors. Furthermore, grounding risks are higher due to the shallower depth.

3. Winged Keel:

For those looking for a middle ground between full keels and fin keels, winged keels provide an intriguing compromise. Originating from the America’s Cup yacht races during the 1980s and 1990s, these unique designs feature additional horizontal wings near the bottom of the main keel shaft.

Their purpose? To improve stability by effectively increasing the lateral surface area without significantly increasing draft. This innovative approach enhances windward performance while maintaining maneuverability and reducing heeling.

4. Bulb Keel:

The bulb keel is another darling of modern sailboat design – especially prevalent among cruising boats aiming for optimal balance between cruising comfort and performance capabilities. These keels utilize a large torpedo-shaped bulb at their base, which concentrates weight lower down for increased stability while reducing overall drag.

Bulb keels offer excellent upwind performance, advanced tracking ability, and minimal lateral movement when navigating waves or choppy seas – all qualities keenly sought after by bluewater cruisers or liveaboard sailors longing for long voyages with maximum safety and comfort.

5. Swing Keel/Centreboard:

Now let’s discuss something adaptable – swing keels (also known as centerboards). This versatile option provides flexibility in both deep water sailing and shallow anchorage areas. Swing keels can be raised or lowered as needed, allowing sailors to decrease draft in shoal waters and subsequently improve maneuverability, while also providing deeper draw for enhanced upwind performance on open seas.

The ability to retract the keel provides opportunities for exploring hidden bays, rivers, or other areas inaccessible to boats with fixed keels. However, this convenience comes with a downside. The mechanism required for raising and lowering the keel may add weight to the boat and increase maintenance requirements.

To conclude, understanding sailboat keel types is crucial when choosing a vessel that aligns with your sailing goals and needs. Whether you prioritize stability, speed, maneuverability, or versatility depends on where and how you envision your nautical adventures unfolding. We hope this comprehensive guide has shed light on the various options available in their witty and clever explanations – setting you on a course towards well-informed decision making when it comes to sailboat keels.

Choosing the Right Sailboat Keel Type for Your Needs: Step-by-Step Process

Purchasing a sailboat is an exciting venture, but it can also be quite overwhelming when faced with the multitude of options available. One crucial decision to make is selecting the right keel type for your sailing needs. The keel plays a vital role in determining the stability, performance, and maneuverability of your sailboat. Hence, understanding the various keel types and their features will help you make an informed decision. In this blog post, we will take you through a step-by-step process to choose the ideal sailboat keel type tailored to your specific requirements.

Step 1: Assess Your Sailing Goals Before delving into technical details, it’s important to assess your sailing goals and preferences. Are you looking for a vessel suitable for racing or one geared towards leisurely family outings? Do you plan on venturing into shallow waters or embarking on long offshore trips? Determining your primary sailing objectives will provide essential insights that shape your keel choice.

Step 2: Understand Different Keel Types Next, let’s explore the common types of sailboat keels:

1. Fin Keel: Also called a modern fin keel with a bulb, this design offers excellent performance and stability even in strong winds. It reduces drag significantly due to its sleek profile while enabling better upwind pointing ability.

2. Full Keel: A traditional full keel provides exceptional directional stability but may compromise maneuverability. Ideal for offshore cruising, it offers reduced rolling motion and enhanced safety during heavy weather conditions.

3. Wing/Daggerboard Keel: This versatile configuration combines aspects of both fixed keels and centerboards/daggerboards by retracting partially or completely when needed. This allows maximum flexibility when navigating shallow waters or adjusting for varying wind conditions.

4. Bilge Keel: Employed mainly in smaller boats, bilge keels consist of two shorter keel sections placed on either side of the hull. This design enhances stability at rest and allows for grounding without damage.

Step 3: Assess Pros and Cons Now that you understand the different keel types, it’s time to evaluate their pros and cons based on your sailing objectives:

– Fin Keel: Pros: Excellent upwind performance, great stability, higher speed potential. Cons: Vulnerable in shallow waters, reduced directional stability when not under sail.

– Full Keel: Pros: Superior directional stability, excellent resistance to leeway (sideways movement), better roll dampening in heavy conditions. Cons: Lower maneuverability in tight spaces or strong winds, reduced speed potential.

– Wing/Daggerboard Keel: Pros: Versatile and adaptable to changing conditions, improved windward performance when centerboard is down. Cons: Higher maintenance requirements compared to fixed keels.

– Bilge Keel: Pros: Enhanced stability at rest, shallow draft capability for exploring shallower waterways. Cons: Reduced pointing ability and performance, may experience more leeway compared to other keels.

Step 4: Seek Expert Advice If you’re still unsure about which keel type aligns best with your needs after assessing the pros and cons, consider reaching out to a knowledgeable yacht broker or marine expert. Their expertise can assist you in making an informed decision based on factors such as boat size, intended usage area (inland lakes vs. open ocean), and personal preferences.

Step 5: Test Sailboats & Consider Trade-offs Once you have narrowed down your options based on previous steps’ evaluation criteria, take the opportunity to test-sail different boats embodying varying keel configurations. Experiencing firsthand how each sailboat handles will give you valuable insights into their capabilities and limitations. Consider trade-offs regarding aspects like speed versus maneuverability or comfort versus stability before making your final decision.

In conclusion, selecting the correct sailboat keel type requires careful consideration and an understanding of your sailing goals. By following this step-by-step process, you’ll be equipped with the knowledge needed to choose a sailboat that perfectly aligns with your needs. Remember, there’s no one-size-fits-all answer – it’s about finding the ideal balance between performance, stability, maneuverability, and suitability for your intended purpose.

Exploring Different Sailboat Keel Designs: A Closer Look at the Options

When it comes to sailing, the design of a sailboat’s keel plays a critical role in its performance and overall handling. A well-designed keel can greatly enhance a boat’s stability, maneuverability, and efficiency on the water. With various options available in the market, it’s important to understand the differences and benefits associated with each type of sailboat keel design.

One commonly found keel design is the full keel. As its name suggests, this type extends from the bow to the stern, providing extensive support and stability to the boat. Full keels are known for their ability to track straight in rough conditions and offer excellent resistance against sideways forces such as wind or waves. This makes them well-suited for long-distance cruising and offshore sailing adventures. Additionally, full keels often have a shallower draft which allows access to more shallow waters, making them versatile for exploring coastal areas.

On the other end of the spectrum is the fin keel design. Unlike full keels, fin keels are shorter and narrower, located primarily beneath the boat’s center of gravity. This leads to improved maneuverability and allows sailors to make tighter turns more easily. Fin keels also tend to have a deeper draft which provides better upwind performance by reducing side slippage while maintaining stability.

A variant of fin keels is bulbous or winged-keels. These designs feature weighted bulbs at their lower ends, enhancing stability while still allowing for efficient upwind sailing. The added weight at the bottom reduces heeling angles during strong winds while optimizing lift characteristics under sails.

For those seeking enhanced speed capabilities with reduced drag underwater, there are high-performance sailboats that incorporate daggerboard or centerboard designs. Daggerboards slide vertically through slots on either side of a boat’s hull when deployed during sailing operations but can be retracted when not needed. They offer tremendous flexibility due to adjustable positions based on wind conditions—providing sailors an opportunity to optimize lift and reduce drag accordingly. This keel design is often favored by competitive racers who prioritize speed and agility over stability.

Lastly, a popular modern innovation is the canting keel. This keel design consists of a fin that can swing out to either side of the boat via a mechanism controlled by hydraulics or other means. The ability to adjust the angle of the keel allows for advanced maneuvering and optimizing performance based on current conditions. Canting keels are commonly found in high-performance racing yachts where every degree counts in gaining a competitive edge.

When deciding on the most suitable sailboat keel design, it ultimately depends on your intended use, sailing goals, and personal preferences. Cruisers may lean towards full or bulbous keels for their stability and versatility, whereas racers seek the swift performance offered by fin or daggerboard designs.

Whichever sailboat keel design you choose, understanding its characteristics and how it aligns with your sailing objectives is vital. Consulting with experienced sailors or marine professionals can help you make an informed decision when selecting your dream sailboat—a vessel that will carry you gracefully through all your aquatic adventures.

Frequently Asked Questions about Sailboat Keel Types: Get Answers Here!

Welcome to our blog where we aim to satisfy your curiosity about sailboat keel types! Whether you’re a seasoned sailor or just getting started in the world of sailing, understanding the different keel designs is crucial for optimizing your boat’s performance on the water. In this article, we’ve compiled some frequently asked questions to provide you with comprehensive answers and shed light on this important aspect of sailboats. So let’s dive in!

1. What is a sailboat keel? A sailboat keel refers to the underwater structure attached at the bottom of the hull that provides stability and prevents excessive sideways drift. It essentially acts as a counterbalance against wind forces acting on the sails, allowing the boat to maintain an upright position.

2. How does a sailboat keel work? The primary function of a keel is to create lift in the water as it moves through it. This lift opposes and balances the lateral forces generated by wind pressure on sails, keeping the boat from being pushed sideways or capsizing. Additionally, by increasing drag and resistance, it also helps prevent excessive speed or slipping sideways when sailing upwind.

3. What are different types of sailboat keels? There are various sailboat keel designs tailored for specific purposes:

– Fin Keel: The fin keel is one of the most common types characterized by its long, narrow shape extending vertically downwards into the water beneath the boat. It offers excellent upwind performance while minimizing drag, making it ideal for racing or competitive sailing.

– Wing Keel: A wing keel features two smaller fins (wings) positioned near its base instead of one central fin like traditional fin keels. This design aims to improve stability while reducing draft depth, enabling boats to navigate shallower waters without sacrificing performance.

– Bulb Keel: Bulb keels have an additional weighted bulb located at their lower end designed to enhance stability and reduce drag even further. These keels are often found on performance cruisers or racing yachts, offering enhanced righting moments and improved overall sailing performance.

– Full Keel: On the other end of the spectrum, full keels extend along the entire length of the boat’s bottom. They provide excellent stability but tend to sacrifice maneuverability and speed in favor of increased seaworthiness, making them well-suited for long-range cruising or bluewater sailing.

4. Which sailboat keel type is best for me? The ideal keel type depends on your specific sailing needs and preferences. If you’re primarily focused on racing or want a higher level of maneuverability, a fin keel with a bulb might be more suitable. However, if you prioritize stability and plan to embark on extended journeys or offshore passages, a full keel could be an excellent choice.

5. Can I modify my sailboat’s keel? Modifying a sailboat’s keel is generally not recommended as it can significantly alter the vessel’s balance and stability characteristics. Unless you have extensive knowledge and expertise in naval architecture, it’s best to consult with professionals before considering any modifications.

We hope this FAQ section has answered some burning questions about sailboat keels! Choosing the right type for your vessel will greatly impact your sailing experience, so take the time to research and understand each design’s advantages and limitations. Whether you’re aiming for speed, stability, or versatility – happy sailing!

Benefits and Drawbacks of Various Sailboat Keel Types: What to Consider

When it comes to choosing the perfect sailboat for your seafaring adventures, one important factor that often gets overlooked is the type of keel. A sailboat’s keel plays a crucial role in stability and maneuverability, making it essential to carefully consider the benefits and drawbacks of various keel types before making a decision. In this blog post, we will explore these different types and help you understand what factors should be considered.

1. Fin Keel: Fin keels are among the most common types found on modern sailboats. They feature a deep, narrow profile that extends vertically from the hull’s bottom. One significant benefit of fin keels is their excellent upwind performance due to their low drag and efficient water flow around them. This allows for better pointing ability and higher speeds when sailing close to the wind. However, fin keels also have some drawbacks worth considering. Due to their depth, they may limit access to shallower waters and make grounding more hazardous. Additionally, their narrow profile can result in reduced stability compared to other keel types in rough conditions or during sudden gusts of wind.

2. Wing Keel: Wing keels are designed similarly to fin keels but have two small wings extending horizontally from either side of the main fin. These wings increase the overall surface area of the keel, providing additional lift and improved stability compared to fin keels. One significant benefit of wing keels is their ability to handle shallow waters more effectively than other types without compromising performance significantly. The extra surface area also helps minimize leeway or sideways drift when sailing downwind. Despite these advantages, wing keels may present some trade-offs. The enlarged wings can induce additional drag, slightly reducing speed potential in certain conditions such as upwind sailing or going against a strong current.

3. Centerboard or Swing Keel: Centerboards or swing keels offer versatility by providing both draft adjustability and easy access to shallow waters. These keels are retractable, allowing them to be raised when navigating in shallow areas and lowered for enhanced stability in deeper waters. The main benefit of a centerboard keel is the ability to explore more secluded areas that may be inaccessible with fixed keels. They also offer better windward performance than wing or fin keels when fully deployed. However, the design limitations of centerboards can result in reduced overall lateral stability compared to fixed keels. Additionally, the mechanism used for raising and lowering the centerboard can be prone to maintenance issues or potential failure if not properly maintained.

4. Full Keel: Full keels, also known as long keels, are characterized by their extended length from bow to stern. This type provides optimal directional stability and contributes greatly to reducing leeway and weather helm even in challenging conditions. One of the primary benefits of full keels is their seaworthiness and ability to maintain course easily while cruising offshore. They tend to track well and inspire confidence in rough seas. Nevertheless, full keels have some drawbacks that should be considered. Due to their larger surface area, they generate more drag than other types of keels. This additional resistance can slightly reduce speed potential, especially in light winds or when sailing against strong currents.

In conclusion, choosing the right sailboat keel type is a critical decision that requires careful consideration based on your desired sailing conditions and preferences. Each type comes with its own set of benefits and drawbacks that need evaluation depending on factors such as intended use, cruising grounds, draft requirements, and personal skill level. By understanding these nuances and making an informed choice, you can ensure an enjoyable and safe sailing experience on whichever sailboat you ultimately decide upon.

Beginners’ Guide to Sailboat Keel Types: Everything You Need to Know

Welcome aboard to our Beginners’ Guide to Sailboat Keel Types: Everything You Need to Know! Whether you’re a novice sailor or an experienced mariner looking to brush up on your knowledge, understanding sailboat keel types is essential for enjoying a smooth sailing experience. So hoist the sails and let’s dive in!

Keels play a crucial role in stabilizing sailboats by counteracting the force of wind pushing against the sails. The right keel type ensures optimal stability, maneuverability, and overall performance under various conditions. Let’s explore some of the most common sailboat keel types you’ll encounter on your seafaring adventures:

1. Full Keel: Picture yourself cruising on a classic yacht from a bygone era – chances are it has a full keel. This traditional design encompasses a long, deep fin that extends from bow to stern, providing excellent directional stability. Full keels are ideal for longer voyages as their heavy displacement reduces rolling motion, making them resilient in rough seas.

2. Fin Keel: On the flip side of the spectrum lies the fin keel – sleek, modern, and agile. Fin keels feature a shorter but more slender profile compared to full keels, extending from just below the hull near the bow and terminating towards the stern. Their reduced surface area allows for increased speed through water while facilitating easy maneuvering and quick responsiveness.

3. Wing Keel: Imagine having wings underwater – that’s precisely what you’ll find with wing keels! These innovative designs incorporate additional extensions (wings) on either side of the main fin, increasing lateral resistance as well as stability. Wing keels offer superb shallow-water cruising capabilities, allowing sailors to explore coastal areas with ease.

4. Bulb Keel: Don’t be fooled by their name; bulb keels are anything but dull! Often seen on high-performance racing yachts or larger cruisers aiming for speed, this keel type features a lead bulb at the tip of a narrow fin. The added weight significantly lowers the boat’s center of gravity, enhancing stability and reducing heeling (sideways tilting) when harnessing strong winds.

5. Bilge Keel: If you’re looking for versatility, bilge keels are your go-to option! As the name suggests, these twin keels are positioned symmetrically on each side of the sailboat’s hull. Bilge keels provide great stability both underway and at rest while also enabling easy beaching or grounding in tidal areas. Their unique design allows for exploring shallow waters without compromising maneuverability.

As with any sailing endeavor, it’s important to remember that each sailboat keel type comes with its own set of trade-offs. Factors such as sailing conditions, intended use (racing vs. cruising), and personal preference will ultimately guide your choice.

So there you have it – a comprehensive overview of sailboat keel types to set your seafaring journey on the right course! Whether you opt for the classic elegance of a full keel or the nimble agility of a fin keel, understanding these different types empowers you to choose wisely based on your specific needs and aspirations as a sailor.

Now, all that’s left is to chart your course and let the wind fill your sails as you embark on countless exciting adventures across vast oceans or tranquil lakes. Happy sailing!

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Published on January 18th, 2017 | by Assoc Editor

Performance Pros and Cons of Keel Types

Published on January 18th, 2017 by Assoc Editor -->

By Chris Beeson, Yachting Monthly

James Jermain has tested hundreds of yachts in his 30 years as Yachting Monthly’s chief boat tester, here he looks at the main keel types, their typical performance and the pros and cons of each type of keel.

The performance and handling of a yacht depends on many things, but perhaps the most important single feature is the shape of the hull and the profile of the keel. Over the years hulls have become shallower and keels narrower, but for many types of sailing this progression is not necessarily progress. Of the various shapes that have evolved, each has its own advantages in different circumstances. Here is a run-down of how they may fit your sort of sailing.

Fin Keel with Spade Rudder This keel type has a low wetted surface area and aerofoil shape, which means speed and agility. It is the most common modern option, usually combined with light but beamy hulls with high freeboard.

The Pros for General and to Windward sailing of the fin keel include: * Low wetted surface and good aerofoil shape means good speed, high pointing and quick tacking * Light steering * Best designs can slice through heavy seas in reasonable comfort

The Cons for General and to Windward sailing of the fin keel include: * High volume, light-weight designs can be lively and tiring in heavy weather * Flat sections can cause slamming * Less steady on the helm, requiring more work and concentration * Strong tendency to round-up when hard pressed * Generally require earlier reefing * Can be unstable when hove to

Downwind sailing pros of the fin keel include moving fast through the water and the boat will be quick to surf and may even plane. Cons of the fin keel are that the boat can broach easily and suddenly or it can be directionally unstable and hard to control in heavy conditions.

Under power, boats with the fin keel have precise handling and turn tight and quick, and some handle almost as well astern as ahead, while there is a limited lateral area so the boat may be susceptible to beam winds at low speeds, and an unattended helm can slam over suddenly.

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Keel types and what they say about sailors.

I tend to think that keel type is only one variable, the others being hull form and rig. Bob Perry says don't try and defend the full keel on its performance merits... Fair enough, but how do you define performance? I wonder if a lot of the grumbling about fin keels hasn't more to do with the fact that so many modern designs are inherently compromised in the quest for speed and luxury accommodations. Sadly, a lot of modern design is a reflection of society at large, where people simply don't have any time... As you alluded to, it depends on what your priorities are. Does "sailing" mean racing around the cans with evening cocktails and wife swapping in the marina, or bluewater passage-making? I will say that when you're 200 miles out in the Gulf of Alaska, and it's sketchy enough that the kids are scared silent, and the wife is giving you "that look", the ability to point a couple degrees higher and wring another knot out of a reach suddenly takes a backseat.

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What is a Boat Keel? & What Does It Do? – Detailed Explanation

Written by J. Harvey / Fact checked by S. Numbers

Knowing the different parts of a boat is important for any mariner. If you look at your vessel exterior, one of the things that’s noticeable is the keel. But what is a boat keel and what does it do?

The keel is a horizontal structure at the bottom section of the hull, which acts as the boat’s main support. We’ll cover keel definition boat use and other relevant information.

Keep reading to learn more.

Table of Contents

The Boat Keel and What It Does

6. centerboard and swing, frequently asked questions.

The keel of a boat is a beam that acts as structural support for the hull and entire vessel. It has many types, and varying designs lead to differences in appearance, with some being longer and extending deeper into the water.

However, serving as support for the hull is not the only purpose of a keel on a boat. It also counterbalances a vessel, which helps to keep it in place and not be displaced by external factors. It is also partially responsible for moving a boat forward and aids steering.

The keel of a ship functions similarly to the keel on boat, serving as the backbone and ballast. It is often the first thing to be constructed on a ship.

Types of Keels

This type usually covers the entire length of the vessel and is one of the most common types used. This keel offers a high degree of safety, owing to its very stable performance along with the ability to run through sand without breaking off.

This is similar to the full keel but shorter, running less than 50% of the length of a vessel. This difference allows it to contribute to a boat’s ability to turn while also giving improvements to its speed. This type is commonly found in racing models.

This keel boat part is similar to the fin, except for the bulb attachment at the bottom, which resembles a torpedo.

The shape of the bulb also makes it less likely to be damaged by contact with rocks, and this type is excellent for cruising.

This design extends the length of the keel, making it similar in appearance to an airplane wing. This design allows a vessel to turn and maneuver more easily, but it is more susceptible to breaking or digging into the ground.

Instead of just one at the center, the bilge keel has one for each side of the hull. A vessel with this type of keel has less roll, which gives better comfort on the water. It also has a lower draft and allows easier anchoring on shallow waters.

These are two different types of keels but are grouped because of their similarities in design. These can adjust their length, making them usable for both deep and shallow water. However, centerboards only partially retract, while swing types have their entire length fully adjustable.

These have the advantage of adjustability but less performance, and they also have more components that require checking compared to fixed keels.

This is similar to the swing keel in that its entire length is connected to a hinge at the bottom of a sailboat but adjusts from side to side, starboard to port, and vice versa.

It can boost speed and maneuverability by wetted surface reduction and weight shifting. This is often used for racing vessels but is still considered experimental as there is a high rate of failure due to its reliance on hydraulics.

Hull and keel: what is the difference?

The keel hull confusion likely stems from the fact that the keel is often part of the hull. However, they are two entirely different things, since the hull is the main body of the boat while the keel is a beam that is connected to the bottom of the hull and may extend farther down from it.

Do all boats have a keel?

Most boats do, but not all boats, as flat-bottomed ones are the exception. The keel boat Lewis and Clark Expedition used in 1803 is a well-known example. This was a barge, a type of flat-bottom vessel that was a boat without a keel.

How is the keel of the boat different from the keel at the bottom of a ship?

Both ships and boats have keels that function in similar ways, but how they are constructed and even the keel shape are different. While most types of sailboat keel are fin-like in appearance, a keel ship needs to be much wider to be able to support the entire ship’s size.

Knowing what is a boat keel is a very important matter that you should no longer have trouble with. Now, you can move on to learning other major parts of vessels. Just remember to consider the draft and use a boat keel guard to safeguard your vessel.

Which type of keel is best in your opinion? Tell us all about it in the comments section below. We’ll be waiting to hear from you.

Remember to boat safely.

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Boat Keels & Fins: 7 Types Explained (For Beginners)

A keel is basically a structural component of a boat or ship which looks like a fin that extends at the bottom of a boat on the center-line.

A keel of the boat is usually the first component that is constructed while building a boat. The main purpose of a keel is to offer both strength and balance to a ship or boat while it is in the water.

These keels are available in different designs, as explained below:

Table of Contents

7 Types of Boat Keels Explained

Keels may be found in six varying designs, giving rise to six keel types.

They include:

• Bilge keels
• Centerboard keels
• Canting keels 

1) Full Keels

This particular keel by design covers at least half of the boat´s length.

It contains a forward edge that bends upwards, while its aft edge usually links to a rudder. This type of keel has a key advantage of providing directional stability as well as relatively safe and strong grounding of the boat or ship.

When referring to safe grounding, the full keel is safer if the boat gets to lie on hardened ground.

The full keel offers a stable and strong balancing surface for the hull whether the boat is along the coast or while traveling.

A boat or ship which is made with a full keel rides smoothly while traveling in the water, providing great directional stability. For instance, if the full keelboat is well balanced, it enables a boat to stay in the compass direction with the keel keeping the boat in a steady direction.

A full keel design is the traditional style of older wooden boats and many newer boats.  It has many years of experience that provides a comfortable and safe boat. 

2) Fin Keels

This type of keel has a length that is less than half of the hull length. It is designed with a flat shape that is sharp-pointed at its trailing edge and resembles a shark’s fin. This type of keel is very fast , it contains less wetted surface as compared to full keels, and it also has a deeper draft than the others.

Often, the deeper the fin keel´s draft is, the better it makes a ship or boat sail.

When it comes to speed and racing, as well as performance, the fin keel is unbeatable.

3) Bulb Keels

This particular keel is often referred to as a shoal draft fin keel. Typically, a deep fin keel is made shorter and then connected with a torpedo-like bulb made from lead material at the bottom of the keel.

It is specially designed to be shallow to allow sailing or cruising within the Bahamas or the Chesapeake Bay as well as other areas with shoal water depths.

However, this design does not significantly compromise the boat´s performance since they have been used on older racing sailboats.  

If you are planning to sail over shoal waters, a bulb keel may be appropriate.  Sometimes, they are not as shallow as other special full keelboats, however.

4) Wing Keels

The Wing Keel may be used as an alternative when sailing in shoal waters.

This does not use one bulb at the bottom of the keel; instead, it makes use of two plates that are attached laterally at the bottom of the fin keel.

This type is considered by some to be better when it comes to performance as compared to bulb keels since it minimizes tip vortex turbulence while sailing. Its draft is usually less.

Additionally, since the two sides are designed in a manner that they offset each other, as the boat heels while sailing, the lateral resistance is not reduced as much as with straight or bulb keels.

However, this type of keel is hard to free in case the boat gets stuck into the muck. Their wings usually go deep and grip onto the bottom of the ground, making it difficult to release once it gets stuck.

Some of the advantages of a wing keel include:

• Minimized draught
• deeper center of gravity, which implies they have better righting moments
• re-engineered water flow above the keel foot implying that they have high efficiency and results in better sailing characteristics.

On the other hand, its disadvantages include:

• It can be more difficult to free if the boat goes aground
• this type of keel is likely to collect objects such as lobster pots as it sails
• and weed may grow at the bottom of the wings, which can become hard to remove.

5) Bilge Keels

These double bilge keel makes a boat stay upright in case of a dried out low tide.

This design results in a shallower draught as compared to fin keels. This feature makes it appropriate for sailing in shallow waters along the coastlines.

However, this type of keel does not perform as well as a single keel and is therefore used for sailing instead of racing.

6) Centerboard Keels

This is yet another alternative that may be used in shoal waters.

The centerboard keel contains a base keel, which has an internal centerboard that rotates downward to create a deeper keel when sailing.

If the waters are deep, the sailor gets better performance with the centerboard down. If you are sailing in shoal waters, you should sail with the centerboard upwards.

This feature is important as it helps to provide the boat with a performance similar to a deep keel and yet to offer improved maneuverability in shoal waters.

However, the main disadvantage of the Centerboard keel is maintenance. It is difficult and problematic when it develops mechanical issues.

7) Canting Keels

This type of keel is the most unique when it comes to performance.

It is connected onto a special (strong) hinge, and as the boat or ship heels, the crew uses hydraulics to move the keel in the windward direction.

This process of moving the keel in a different direction from your heading direction makes it possible to maximize the lateral force and the righting force, to sail faster.

The main challenging posed by this keel is maintenance due to the complex design of the canting keel.  It is usually only found in specialized racing boats.

It has a promising future when it comes to racing, but it is not recommended too often because of its complicated operations.

Common Problems With Boat Keel and Fins

First, fins and keels are not protected from potential external impacts. By their design, they are long components with lever-like arms.

Therefore, if an underwater object was to be hit, like a sunken piece of log or even the sea bed, the force that would result is likely to be multiplied before being re-transmitted onto the entire boat over the keel area.

Therefore, the small surface is likely to encounter excess loads, which may result in cracks.

For instance, on the Chesapeake Bay, the majority of the creeks range from 4.5 -5 feet downwards. Boats and small ships that attempt to get too close to shore may often get grounded at some point. The moment grounding happens, the force which results and exerts pressure onto the keel is strong enough to generate cracks on the keel or along the hull.

The cracks are only physical indications of the damage caused.

For instance, the bolts which are connecting the keel and the hull at the bottom of the bilge may be frequently wet, resulting in bolts rusting and getting corroded.

When this happens, the forces together with rusted bolts will result in the keel falling off. This is dangerous and can cause severe accidents.

When the keel is removed or damaged, and the keel bolts develop holes, it allows water to flow into the hull. If the holes remain in that condition for a while, this may cause the boat to sink as a result of the incoming water.

Also, when the keel has been compromised in some way, the ballast or righting weight, which helps to counter the sails, is eliminated. In this case, if strong wind heels over your boat, it may result in the boat capsizing!

To make it worse, after the ship has capsized, you will not be able to right it since the ballast will not be there. Therefore, when a keel is destroyed, it makes the sailing horrible!

Finally, if you want to sail a boat with a fin and keel, it is recommended to avoid sailing through shallow waters. In case your boat gets grounded, the underwater appendages may be destroyed, and repairing such elements is very expensive and time-consuming.

You should take a fin keelboat or ship as a deep water machine! In deep waters, it glides over and through the water waves efficiently and easily.

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What are the pros and cons of different keels?

We all sail for different reasons, in different cruising grounds and use our yachts differently, so it makes sense that there is no one-size-fits-all keel design. At Sirius, however, we like to make the perfect yacht for each individual owner. One of the ways we serve our customers is our choice of keels – at least six different options for each model. It’s one of the ways we stand out – or should that be stand up?

We offer three styles of keel: fin, twin and lifting swing keel. All of our keels excel in many ways, but every design does have drawbacks – this is not unique to Sirius, but the keel affects the way you use the boat, so it’s important to choose the right one for you.

These are the keels we currently offer:

Standard Fin (310 DS, 35 DS, 40 DS) Performance Fin (310 DS, 35 DS, 40 DS) Medium Fin (310 DS, 35 DS, 40 DS) Shallow Fin (310 DS) Shallow Twin (310 DS, 35 DS, 40 DS) Performance Twin (35 DS, 40 DS) Lifting Swing Keel (310 DS, 35 DS, 40 DS)

Does the choice of keel compromise ocean capability?

For Sirius yachts, absolutely not. It’s important to realise that choosing one keel style over the other does not affect the yacht’s righting moment or compromise its ocean-going capabilities at all!

Whichever keel you choose, deep or shallow, twin or fin, they all have the same stability. This is achieved by putting more weight in the bulbs of the shallower keels as the shorter lever can be balanced with higher weight. Most of the blue water cruising and circumnavigations in Sirius Yachts have been made with twin-keel or reduced/shallow fin keel yachts.

Does keel choice affect performance?

As our shallow keels are heavier the weight dampens the yachts’ motion at sea, but as a downside, you have more weight to move with sails or engine. Once you’re moving there isn’t a difference but when tacking or gybing, or when not steered well, you will lose a bit in sailing performance. The shallower draught yachts also lose a few degrees to windward compared to their deeper keeled sisters, but they are still good all-round performers. Our customers with racing backgrounds always try to go for a keel as deep and light as their sailing area permits, either with a single or twin keel.

Pros and cons of fin keels

The standard keel on our yachts is a fin keel. Most sailing boats today use a fin keel because it gives a good all-round performance on all points of sail. By keeping the ballast lower it gives the most comfortable motion. The main downsides are that the draught (the depth of water required to stay afloat) is the greatest, and it’s very important to avoid running aground on a falling tide. Fin keel boats cannot dry out without additional support, either from a harbour wall or by fitting a pair of beaching legs. Some fin keel yachts are not built strongly enough to stand on their keels when out of the water, so they can’t dry out alongside a harbour wall and they need to be kept in a special cradle when stored ashore to avoid the risk of the hull deforming under its own weight. By contrast, all Sirius yachts can stand on their keels for any length of time with no problem at all.

We offer four types of fin keel. The standard fin is available on the 310 DS, 35 DS and 40 DS and is fully cast-iron. It offers the best value, good performance, and excellent responsiveness. It is the deepest of our fixed-keel options, so if you want less draught you may want to look at our other fin keels.

We also offer a performance fin keel for all our models. This uses a cast iron fin with a lead bulb at the tip (bottom). The structural strength of cast iron means the fin is the slimmest profile, but lead is denser than iron so the same volume of lead will weigh around 1.4 times more than cast iron, giving more righting moment. The heavier, softer lead down low has less volume in the bulb so achieves a slimmer profile with less drag and therefore better performance.

A lead bulb is also safer if it hits something. Lead can absorb 60% of the energy in flexing and deformation so that only 40% of the force will be transferred to the laminated structure of the keel reinforcement. A lead bulb is very forgiving and easy to reshape and will not start to rust where the coating is damaged. We can use less volume of lead than iron, and achieve better stability than a wholly cast-iron keel. We can also reduce the depth of the keel and retain excellent stability. However, lead is more expensive than cast iron and the bulb must be attached very securely to the iron fin, so this option does cost more.

If you want less draught, we also offer a medium fin. This reduces the draught of the 310 DS and 35 DS by around 40cm/1ft 4in and 55cm/1ft 9in on the 40 DS. Like the performance fin, it uses a cast iron fin with a lead bulb. To retain the keel’s grip in the water it has to have a longer chord (the distance from fore to aft). While this gives the boat better directional stability, it does make her a little less responsive and a little slower to manoeuvre.

On our 310 DS, we offer a shallow fin option – a special version for very shallow cruising grounds. This fin keel offers the least draught of any of our fixed keel options at 1.15m/3ft 9in and draws 10cm/4in less than the twin keel version. The keel has a significantly longer chord (2.24m/7ft 4in compared to 0.7m/2ft 3in of the standard keel) so she has the reassuring directional stability of a long-keeled yacht but with better manoeuvrability.

Pros and cons of twin keels

Our twin keels are the most popular option. About 70-80% of all Sirius Yachts are delivered with them – and on the 40 DS it’s 90%. Some folk still believe there is a big performance penalty with twin keels. In the past this used to be true but it’s no longer the case with modern twin keel designs, from Sirius at least. We have conducted many two-boat comparison tests, often battling for hours, by ourselves, with owners, and for sailing magazines and we have found that there may only be one or two boat lengths of difference at the end of a long windward leg, if at all. At the end of many of these comparison tests, the crews could not point out which of the boats had the twin keel.

If you cruise tidal areas, twin keels will reward you time and time again. Not only do they give you a shallower draught than the typical fin keel, they also give you the ability to dry the yacht out, whether that’s for a motion-free night’s sleep, to explore cruising grounds others cannot reach, or just for cheaper mooring and maintenance costs.

We offer two styles of twin keels; performance and shallow draught. Both options have a cast iron fin with a lead bulb. The performance keels have a deeper draught and a thinner chord so they act and feel a bit livelier when sailing and manoeuvring. The shorter keels have a longer chord, but give you the ability to navigate shallower areas. Like all keel designs, twin keels do have some downsides. They are more expensive than fin keels, and when you’re sailing fast in choppy seas at a steep angle of heel, you can occasionally get a slapping sound when an air pocket is caught and pressed out under the windward fin. Lastly, we’ve yet to meet an owner who enjoys antifouling between the keels. Thankfully it only has to be done once a year and with twin keels you might get away with doing it less frequently. A twin keel yacht can be kept on a drying mooring, where fouling is reduced because the hull spends more time out of the water. And when you’re off cruising it’s easy to give the bottom a quick scrub while the yacht is dried out.

Our yachts will happily sit on their keels on a hard surface, like a drying grid, or for winter storage but on softer surfaces we use the rudder for additional support. The rudders on our twin keel yachts are specially reinforced for this: we use a Delrin sheave to take the weight of the hull and the tip of the rudder has a wide, foil-like foot to spread the weight.

A lifting swing keel

We are one of a few manufacturers to offer a lifting swing keel. There’s a lot of confusion with the term ‘lifting keel’, it seems to encompass all yachts that have centreboards, variable draught, lift-keels or swing keels. To us, a lifting keel boat should have all the ballasted weight of the boat in the keel, and that keel needs to be retracted into the hull.

Technically, a lifting keel is a keel that can be lifted or lowered and gives the boat the ability to dry out when the tide goes out. A lift-keel is a ballasted keel that raises and lowers vertically. A swing keel has a ballasted fin that has a single pivot point and the keel swings up into the boat. There are other variants of design, for example some have a lifting keel to reduce the draught of the vessel but they cannot dry out on it, others have a ballasted keel and ballasted grounding plate. All these examples have a keel that does two things: keep the boat upright and stop her sliding sideways. Our swing keel is designed with a NACA profile to give the most efficient performance.

Centreboard yachts have a centreplate to provide grip in the water and reduce leeway. The plate may carry only 15-20% of the ballast but the rest of the yacht’s ballast is within the hull and/or in the grounding plate. This is called an “integral keel” and is more common as it’s less complicated to build. The lower a yacht’s ballast is located, the better her stability, the more comfortable her motion and the better she stands up to her sail area. The most efficient place for the ballast is as low down on the deepest keel possible – this is why race boats have deep skinny keels with large torpedo-shaped bulbs on the bottom, but they don’t make practical cruising sailboats.

Our keel designs have more weight in the tip (bottom) – using a bulb on the fin and twin keel design and flaring the lower sections on our lifting swing keel yachts. You don’t have this with centreboard and integral keel yachts.

It might be surprising, but a lot of owners come to us thinking that a lifting swing keel is the best option for them. Sometimes it is, but about 98% of customers who approach us because we offer swing keels end up sailing away on a twin-keel Sirius.

The downsides of a lifting keel

A lifting swing keel does give you more cruising options. It will lift should you run into something and, of course, it gives you the shallowest draught. But that difference is only 40-50cm (1ft 4in to 1ft 8in) less draught than our shallow twin keel option. The lifting keel increases the complexity of the build and the final cost of the yacht; it also sometimes limits the internal layout and engine drive options, and you need to have twin rudders too. Twin rudders make the boat less manoeuvrable in a marina – you can opt for a third central rudder which does improve the handling, but again comes at an extra cost.

On the lifting swing keel, 40 and 310 owners are restricted to the use of a shaft drive, which is less efficient and you have to accept a bit more noise and vibration. When drying out, the drive is more vulnerable to damage, whereas it’s totally clear when taking the ground on twin keels. With twin keels, you also do not have to worry about something sticking out of the beach or stones lying around because the hull is high above the ground. With the hull up high, you do not have to dig a hole in the sand and slide down on your stomach to check or change your anodes as you would on a swing keel.

Sailors who are attracted to the idea of a lifting swing keel should carefully consider the pros and cons to compromise the least. When owners understand the repercussions of choosing a lifting keel yacht, many of them feel it restricts their options too much. They could have a lifting keel or they can sail with twin keels, dry out, have better close-quarters handling and save money in the process. Unless you need the shallowest possible draught – 0.75m (2ft 5in) on the 310 DS, 0.9m (2ft 11in) on the 35 DS or 0.95m (3ft 1in) on the 40 DS – a twin keel might well be a better option.

How are the keels attached?

The design of the keel is important but the way they are attached is just as important, if not more so. All of our fixed keels are through-bolted. Every keel has a wide flange at the root (top) of the keel and the flange sits into a reinforced recess in the hull. The flange and the recess work together to spread the loads of the keel/s into the yacht’s hull. The keels are bonded and bolted to the hull. We use up to twelve 20mm and 24mm bolts (per keel) and these go through rolled stainless steel backing plates inside the hull to spread the bolt loads evenly into the fully laminated keel grid which goes all the way up to the chainplates and also carries the mast support.

For our lifting swing keel, we laminate a substantial keel box as part of the hull to accept the keel and the hydraulic mechanism needed to retract the keel into the hull. Unlike most other boatbuilders we don’t use a grounding plate to take the weight of the yacht, our yachts sit on the length of the leading edge of the keel. Integral keels with the majority of the ballast in the grounding plates move the ballast (weight) from low down in the keel to inside the hull. This negatively affects the stability as the more weight you have lower down, the better.

We also don’t like grounding plates because they bring the hull in contact with the ground. By leaving 10-15 cm (4-6in) of the keel out of the hull when it’s retracted, most of the time the hull is kept clear of the beach and anything that could damage it.

The problem with too much form stability

With only 15-12% of their ballast in the centreboard, most lifting-keel yachts cannot rely on keel weight for stability so their hulls need to be designed with extra form stability instead. This means the hull sections have to be much wider and flatter. A flat-bottomed hull is not what you want for a comfortable ocean cruising yacht; it isn’t sea-kindly or easy to steer in waves and gusty winds conditions. We don’t make that compromise at Sirius. With all the ballast in the swinging part of our swing keel design, we can use the same seaworthy, ocean-capable hull shape designed for our yachts with fixed keels.

If you don’t know which keel would be best for your Sirius, contact us to discuss the type of sailing you intend to do, where you want to sail and what your cruising aspirations are.

General Manager – Torsten Schmidt SIRIUS-WERFT GmbH Ascheberger Straße 68 24306 Plön/Holstein

Fax: 0049 – 4522 – 744 61-29

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Sailboat Keel Depth: Draft of 9 Common Keel Types

Most sailboats have one of three drafts, based on their keel type. Inland water boats using centerboards have the least draft, while bluewater boat keels run much deeper.

The depth of sailboat keels depends on their design. Boats designed for inland waters usually have a draft of around 0.6m (or 2ft). Bluewater boats can either use a full keel or fin keel. Full keels run on average around 1m (or 3ft) deep. Fin keels, wing keels, and bulb keels run on average 1.8m (or 6ft) deep.

Below, I'll go over each keel type's depth and also show the range of depth based on different boat lengths, both in metric and imperial.

Draft of 9 Most Common Keel Designs

The average depth of different keel types is not readily available on the internet. To find these numbers, I've measured dozens of technical scale drawings of yachts in an old Dutch sailing book published in 1977. The numbers are quite consistent.

In order to keep things simple, I'll go over the rough averages first, before diving into a bit more detail based on boat length. After that, I'll discuss why different keel designs use different depths.

Average depths based on keel type

• Full keel : 0.8m or 3ft
• Modified full keel : 1.2m or 4ft
• Fin keel : 1.8m or 6ft
• Bulb keel : 1.8m or 6ft
• Wing keel : 1.8m or 6ft
• Bilge keel : 0.6m or 2ft
• Daggerboard : 0.6m or 2ft
• Centerboard : 1m or 3ft
• Leeboards : 0m or 0ft
• Canting keel : 5m or 16ft

Keel depths for different boat lengths

Keel Depth Explained

Different keel designs use different depths due to several factors. Fin keels are by far the longest keels, as they use their length to increase the leverage of the ballast. Full keels , on the other hand, require less depth since they carry more ballast and provide more wetted surface, which improves directional stability in itself.

Centerboards and daggerboards are often used in sailboat designs meant for use in inland waters, which is why they run on average less deep, with the daggerboard running the least deep of both at around 60cm or 2ft.

Bilge keels also run less deep, as this design was intended for use in tidal waters, and allows for safe beaching of the boat. The use of two blades instead of one doubles the wetted surface and ballast, allowing for a shoal draft.

Shoal draft simply means the keel doesn't run deep.

How deep should a keel be?

A keel should be deep enough to provide enough wetted surface and enough leverage for the ballast to provide adequate righting moment for the used sail area, while simultaneously allowing access to desired waters.

Righting moment is the most important function of a keel .

For bluewater conditions, the keel tends to be at least 1 meter deep, in order to cut through the surface drift layer of the water.

The water's surface drift layer is the layer of water directly affected by the wind.

For most inland-water sailboats, this translated to a keel depth of between 0.5-1m. For offshore boats, keels tend to be deeper, at 1-1.8m.

Factors that affect keel depth:

• Keel design
• Ballast weight
• Desired sail area
• Usage conditions (inland, offshore, cruising, racing)

How keel design affects keel depth requirement

Keel design plays a major role in the amount of ballast required and the total weight of a sailboat keel .

Full keels span over a longer area fore to aft, which is why they can be less deep while achieving the same amount of wetted surface. They also carry more ballast, which provides similar or more righting moment at lower depths than fin keels.

Since fin keels are generally quite narrow, they need to run deeper to achieve the same amount of wetted surface and to provide a similar righting moment. However, since the ballast is further away from the hull, they can carry less ballast, making the boat lighter overall (and thus faster).

How hull width affects keel depth requirement

How is keel depth measured.

Keel depth is measured vertically from the waterline, which is where the hull touches the water, down to the lowest point of the keel. Keel depth is also called draft or draught.

What is the difference between draft and depth?

Depth is measured from the top of the keel to the top of the deck beam, at the center of its length. It refers to hull depth, as opposed to draft. Draft is measured from the center point at the waterline, down to the lowest point of the keel. It refers to the minimum water depth a boat requires.

When calculating minimum water depth, you want to take your boat's draft , not your boat's depth.

What is depth below keel?

Depth below keel, sometimes called keel offset, or depth below transducer, is the distance between the lowest point of the boat and the ocean floor. It is measured by the depth meter, which often shows it as a negative number.

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Sailboat Keels Explained

What's the Best Keel Design for Bluewater Sailing?

07 Different types of Keels you should know

The keel of a boat is a vital component that helps keep the vessel stable and prevents it from capsizing. The keel is a fin-like structure that extends downwards from the hull and rests on the seabed. This weight distribution helps to keep the boat upright, even in rough seas. The keel also plays an important role in steering the boat. It is common knowledge that the keel of a boat is one of the most important parts of the hull.

However, it is also true that there are many other parts that are equally important to the overall performance of a boat . The keel is used to provide longitudinal stability that allows the boat to move forward or backwards without going out of control. Lateral stability is provided by the rudder.

What does keel do and how does it work?

The keel is a vital part of a boat and it does a lot to keep the boat stable. The keel is located on the bottom of the boat and it helps to keep the boat from tipping over. The keel also provides a lot of stability when the boat is moving through the water. The keel is also responsible for controlling the boat’s direction.

The keel is made up of a flat foot in the center and a flat edge. The keel also has two round weights on each side that are called ballast stones. The two ballast stones are made of lead and they are attached to the keel by an iron rod. The lead balls in the ballast stones will help to keep the boat from tipping over.

Types of keels

There are many different types of keels, and each has its own benefits and drawbacks. In this article, we will explore the different types of keels and discuss of each.

1. Fin keel

There are a variety of different types of keels, each with its own benefits and drawbacks. One type of keel, called a fin boat keel, has become increasingly popular in recent years. The fin keel is the simplest type of keel. It consists of one or more straight fins made out of metal. These fins may be either vertical, which are used on sailboats and kayaks, or horizontal, which are used on motorboats and most small fishing boats.

Fin keels are most commonly used on sailboats, where the keel runs parallel to the center of the boat and is moved up and down by a pulley system.

2. Bulb keel

The bulb boat keel is a recent innovation in boat design that offers many advantages over traditional keels. A bulb boat keel is a truncated cone-shaped structure that is attached to the bottom of a boat’s hull. The bulbous shape creates more lift and stability than a traditional keel, making the boat more responsive and easier to control. Additionally, the bulb boat keel creates less drag than a traditional keel, making the boat faster and more efficient.

The bulb keel is usually made from aluminum or fiberglass, and is very light in weight. In addition to the benefits it offers over a traditional keel, the bulb shape of the bulb boat keel enables it to be attached either vertically or horizontally to the hull of a boat.

3. Twin fin keel

Twin fin keel boats are unique in that they have two fins instead of one. This gives the boat more stability and makes it less likely to tip over. Twin fin keel boats are also easier to maneuver, making them a popular choice for sailing enthusiasts. They can be sailed in both calm and rough waters, making them ideal for a variety of sailing conditions.

4. Ballasted keel

A ballasted keel is a keel that is weighted down to provide stability to a boat. This type of keel is found on many boats and is especially common in sailboats. A ballasted keel can be made from a variety of materials, including lead, iron, or concrete. The weight of the material helps to keep the boat from tipping over and provides stability in rough waters. Some boats have a ballasted keel because they are easier to handle in rough conditions. Other boats have a ballasted keel because they are more efficient than other types of hulls.

5. Skeg or centerboard keel

The Skeg or centerboard keel is a hybrid keel that is made up of two different types of keels. The skeg is the part of the keel that is located in the front of the boat and is made up of a centerboard and a daggerboard. The centerboard is used to keep the boat from slipping sideways and the daggerboard is used to keep the boat from slipping forward. The skeg is used in boats that need to be more stable in rough water. The centerboard is used in a boat that has a very low freeboard or the amount of water over the top of the boat.

6. Bilge keel

A bilge keel is a thin, long and shallow fin extending from the hull of a boat below the waterline. Bilge keels are often fitted to boats with twin hulls in order to improve stability and reduce the amount of roll. They are also common on larger vessels, as they help to prevent the boat from heeling (tilting) too far to one side in high winds or during rough seas. Bilge keels are sometimes referred to as “keel fins”.

7. Foiling keel

Recently, there has been a trend towards foiling keels. These keels are made of carbon fiber and are mounted on top of the boat.

Is a keel guard worth it?

When it comes to boat accessories, one of the more debated items is the keel guard. Some people swear by them, while others believe they are a waste of money. So, what is the truth? Is a keel guard worth it?

The purpose of a keel guard is to protect the keel of your boat from being damaged. This is especially important if you are often in shallow water or if you have a fibreglass boat. A keel guard can protect the boat’s keel from damage caused by ice, rocks, coral and other potential hazards. It also helps prevent accidental damage to the bottom of your boat while it is in storage.

Where you will find good quality keel guard or protector?

Keel guards or protectors can be found in many places, but not all of them are created equal. Some are made of cheap materials that won’t last long and others are made of high-quality materials that will protect your boat for years. So, where can you find best keel guard and protector?

One place to find a high-quality keel guard or protector is on Amazon. Another place is on eBay.

And lastly, you can find a high-quality keel guard or protector at your local marine store.

Related: Best Keel Guard and Hull Protectors

How much does it cost to repair a boat keel?

The average boat keel repair costs between $1,000 and $3,000. However, the cost can vary greatly depending on the damage. Some keel repairs can be as simple as filling in a hole with putty and painting over it, while others may require the entire keel to be replaced. If you’re not sure what’s wrong with your keel, it’s best to take the boat to a marine mechanic for a diagnosis.

How do I know if my boat has a keel?

Some boats do not have keels, while others have more than one. If you are unsure whether your boat has a keel, there are a few things you can do to find out. The easiest way to determine if your boat has a keel is to look at it from the side. The keel is located on the underside of the boat in a small opening that is usually covered with a strip, called a chine.

A few boats may not have this at all and instead have the keel built into the bottom of the hull. If you see a keel on the side of your boat, there is a good chance that it is an integral part of the hull.

In conclusion, there are many different types of keels available for sailboats. It is important to choose the right type of keel for your boat and sailing style.

If you are unsure about which keel is best for your boat, be sure to consult with a professional. They can help you choose the right keel and install it properly for optimal performance.

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What’s Behind Different Keel Configurations by Jim Schmicker

In recent years, the superyacht market has become more focused on greater performance by optimizing all aspects of a yacht’s design, engineering and construction. 

The choice of the keel configuration is surely one of them. 

It’s not surprising that the first three units of the brand new SW105 miniseries will each have unique keel designs to satisfy the requirements of three different owners.

To his end, we’ve asked Jim Schmicker, Vice President of Farr Yacht Design, one of the world’s foremost designer of racing and cruising sailboats, to explain how the choice of the keel design has specific benefits that make it the best choice for a particular owner’s needs.

Jim Schmicker Is Vice President and shareholder of Farr Yacht Design. The company is recognized as one of the world’s foremost racing yacht design studio, based on one of the most impressive winning results records ever compiled by a single company. For more than 30 years, FYD has been developing fast, custom and production cruising yachts. Southern Wind has collaborated with this reputable studio since 1992.

KEEL DESCRIPTIONS

When approaching the cholce of a keel, an owner should be aware that each of the options has advantages and disadvantages but all of them are designed to deliver excellent performance and achieve stringent stability targets while maintaining a similar displacement.

The simplest keel option for construction and installed systems is the fixed keel. The choice of draft for a fixed keel Is decided by balancing upwind performance against reasonable access to ports and anchorages. Reaching and downwind performance is the strongest feature of the fixed keel so long as sufficient stability is achieved. The keel is fabricated out of mild steel plates that are formed and rolled into the correct shape. Considering cost, portions of the keel, such as the leading and trailing edges of the fin, can be CNC machined and the rest hand-faired or the entire keel can be machined. This construction method results in a simple and light structure. Given the shallower draft compared to lifting or telescopic keels a heavier bulb Is necessary to achieve the target righting moment. However, the light fin construction helps to mitigate some of the relatively greater bulb weight. Attachment to the hull is entirely below the cabin sole which facilitates a variety of choices of interior layout with no constraints on either the accommodation or machinery spaces.

Fixed Keel showing Bolt Pattern and Internal Construction

LIFTING KEEL

The lifting keel is a popular choice for superyachts of this size. The ability to raise and lower the keel allows access to ports and anchorages with limited water depth while the deep maximum draft achieves excellent upwind performance. The keel construction is complicated with hydraulic cylinders housed internally to the keel, PLC systems, locking pins to hold the keel In the raised position and adjustable bearing pads to ensure tight tolerances and no movement of the keel In Its trunk while underway. The high number of moving parts and complex hydraulic control systems have associated installation and maintenance costs. The keel trunk takes up significant space In the accommodation but with clever integration with other aspects of the interior its impact can be diminished. The keel is typically constructed out of high strength carbon steel plates welded together and CNC machined to an extremely high level of accuracy. As such, advanced foil sections can be used which results in higher lift to drag ratios being achieved. The lower portion of the keel fin, below the hull in the raised position, is tapered to improve lift efficiency, optimising the amount of surface ares and reducing drag.

Lifting Keel with Tapered Lower Portion Showing Hydraulic Cylinders, Trunk and Bearing Pads

TELESCOPIC KEEL

The telescopic keel combines some of the benefits of the fixed keel and lifting keel. It achieves a similar amount of draft adjustment as the lifting keel with only minor intrusion into the interior. The upper, fixed part of this design is installed partly inside the hull but mostly outside and below the hull surface. The lower, moving part retracts into the upper part and incorporates a foil-shaped shell that slides over the outside of the upper part. Similar to the lifting keel, the telescopic keel is a complex installation with a high number of moving parts and hydraulic systems with associated costs. The fin is typically constructed out of high strength stainless steal plates welded together and CNC machined to an extremely high level of accuracy. The un-tapered planform shape required to house the hydraulic cylinders and structure supporting the lower part results in higher surface area, The fin components have a relatively higher weight and center of gravity.

Telescopic Keel with Un-tapered Lower Portion Showing Hydraulic Cylinders, Internal Structure and Shell

KEEL COMPARISON

Each of the keel designs has specific benefits that may make it the best choice for a particular owner’s needs. In terms of draft, both the lifting and telescopic keels achieve shallow draft (3.15m to 3.65m) without compromising performance as a result of their heavier fins and associated structure. The fixed keel requires an acceptable amount of draft (in this case 4.5 meters) for reasonable upwind performance while still allowing access to the owner’s preferred ports and anchorages. A fixed keel has a much lighter fin and associated structure weight. For the same displacement, it achieves the highest righting moment because the keel has the deepest center of gravity as a percentage of Its draft. A secondary benefit of the fixed keel Is less heeling moment because the sideforce it generates is acting closer to the surface of the water so the fixed keel version operates at a lower angle of heel.

The telescopic keel has the best combination of performance, harbor access and disruption of the interior. Its disadvantages are greater wetted surface, volume outside of the hull and maintenance costs. With specific reference to the Southern Wind SW105 project, because similar displacement was a design requirement, the performance differences between the first three units is not large. However, the deepest maximum draft (5.6m) of the telescopic keel produces the best upwind performance, as a result of its lower induced drag.

The lifting keel (at 5,15m draft) has the next best upwind performance while the fixed keel is strongest in power reaching conditions. For performance versus rating the lifting and fixed keel versions are essentially equivalent over a balanced race course with the advantage going to the lifting keel for more upwind-downwind oriented races and to the fixed keel when the reaching content Is greater. The telescopic keel, with its slightly less efficient keel shape, comes in a very close third place behind the other two options. The initial cost of the fixed keel is the least of the three and ongoing maintenance costs will be less than these of the lifting and telescopic options.

KEEL CHOICES FOR THE FIRST THREE SOUTHERN WIND 105’S

The Southern Wind 105 Is the newest addition to the SWS line of luxurious, performance, blue-water cruising superyachts. The first three yachts constructed will each have unique keel designs to satisfy the requirements of the three owners. The overall parameters of a superyacht of this size, the necessary draft for reasonable upwind performance and the owner’s requirements for keel draft for access to his preferred ports and anchorages have led to fixed, lifting or telescopic keels being viable options.

Design Brief

Desire for an advanced keel design with maximum upwind performance without any significant compromise to the interior layout and saloon space.

Best performance for both racing and cruising and no requirement for a specific minimum draft. The 4.5m draft is designed to achieve the low leeway angles desirable for racing combined with high sailing stability.

Best performance combined with a minimum draft requirement of 3.1m Is the strongest driver of the keel design. Intrusion into the interior is apparent but details of the trunk design allow light across the saloon and avoid a complete separation of the two sides of the yacht.

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Choosing a Blue Water Yacht – Keel Type

Posted Monday 29th June 2015

Over the coming weeks,  Grabau International  will take you through a variety of subjects which encompass choosing the right yacht for blue water adventures. The following guide is not written to dictate what to choose, or to supply a comprehensive encyclopedia of every option and variable, but simply a basic explanation of the main options and some guidance on what to look out for. Finding a yacht will always be a battle of your head over your heart, so the purpose of this guide is to give your head some questions to ask in the hope that an amicable compromise can be made with your heart. Part 3 of this guide looks a the question of keel type.

The type of keel fitted to a yacht is very much intertwined with the hull shape which was covered in part 2  of this guide. Keels use the forward motion of the boat to generate lift and to counteract the leeward force of the wind. In essence, the basic purpose of the keel is to convert the sideways motion of the wind into forward motion. In the case of a sailing yacht, this same keel must also act to provide ballast and righting moment.

Once again, due to the sheer diversity within the yachting spectrum, different keel types work for different purposes. Those looking to go racing will require a deep fin keel or perhaps even a canting keel, whilst blue water sailors may wish to choose from conventional fin keels, encapsulated keels, shoal-draft keels or even lifting keels. For the sailing looking to go creek crawling, lifting keels once again come to the fore along with bilge keels (although these are rarely seen on larger yachts).

Bolted fin keel

By far and away the most common type of keel. Easy to construct and offering loads of variations in profile and dimension. Attachment is usually via acid-resistant stainless steel bolts, although some use mild-steel bolts which are painted and sealed over (making maintenance and inspection extremely important). Mild steel is materially stronger than stainless, so there is no best or worst here, just make sure that they are tight and in good shape! With racier designs, a bolted keel can also be (relatively) easily removed for transport or shipping.

Examples: Beneteau, Jeanneau, Bavaria, Swan, Oyster, Hallberg Rassy, Sweden Yachts et al.

Italia Yachts 13,98 with modern bolted fin keel and ‘T-bulb’

Encapsulated fin keel

This adds a little more security over the universal bolted-fin keel by laminating (or plating) in the ballast. An encapsulated keel can include anything from a glorified bolted keel which has been over laminated, to a complete keel structure filled with ballast. Encapsulated keels usually benefit from a deep keel sump which can be useful for tank location, storage and bilge-pump location. The keel profiles of encapsulated keels tend to be slightly deeper in length which in turn provides more directional stability (which your autopilot or helm will thank you for) at the detriment of close-quarter maneuvering and fast changes in direction.

Examples: Older Oysters, Camper & Nicholson, Trident Warrior 40, Rival Yachts etc.

  S&S Swan 36 with an encapsulated keel

Shoal / Scheel keel

A simple variation of the fin keel, is where the draft is reduced by profiling the bottom of the keel to add further ballast. For tradewind sailing, a deep draft is perhaps not as important as a shallower draft at either end, so many ‘bluewater’ yachts are often equipped with scheel (or shoal) draft. Many yachts are offered with this as an option and sometimes it is possible to swap keels over if the numbers stack up financially.

Examples: Bowman, Rival, Moody, Westerly, Swan (some versions), Pacific Seacraft etc.

Rival 36 with Scheel (Shoal) Keel

Another way to reduce draft and potentially play about with ‘lift’ at the same time. Commonly adopted on larger productionyachts destined for shallower waters (Caribbean or Eastern Seaboard of the USA), but also on high quality cruising yachts in a slightly more paired down fashion (such as seen on Sweden Yachts which have ‘winglets’ rather than a full wing).

Examples: Contest, Sweden Yachts (some versions) etc

 Sweden Yachts 38 wing keel

Lifting keel (centerboard or daggerboard)

Traditionally a niche concept, but now more readily accepted. There will always be the salty-seadog perched on the end of the yacht club bar ready to damn the concept on the basis of un-favourable STIX calculations, but the fact remains, more often than not, your ballast is in the boat rather than dangling on the end of the keel; and in the ‘perfect storm’, you can wind up the keel and slip down waves which would cause any traditionally-keeled vessel to trip over herself. The practicalities at point A and point B are also fairly obvious. In tidal areas you can dry out (if the keel retracts fully or aligns with twin rudders to create a ‘tripod’ support), or wind the keel up to get over a harbour sill at your convenience. In terms of downsides, anything involving moving parts adds complication and the potential for breakage or jamming. Common sense, regular maintenance and proper usage (most lifting keel yachts can only be used with the keel fully up or down) will go a long way to mitigate these shortcomings.

Examples: Southerly, Ovni, Feeling, Allures, Garcia, etc

Classic Southerly dried out with lifting keel

Extremely rare on any modern production yacht other than perhaps the Island Packet designs. Effectively, the keel becomes part of the hull, beginning at the bow and working its way to the stern. The advantages and disadvantages of the encapsulated fin keel are all here, but amplified by a factor of 10. Not a bad option if you want to spend your days crossing oceans, but not so hot if you like spinning in and out of marinas or thrashing around the cans.

Examples: Island Packet, Nauticat, Vancouver, Hans Christian etc

Nauticat 44 with a long keel configuration

Fairly uncommon on yachts destined for bluewater sailing with the exception perhaps of the extremely clever RM Yachts range. Ideal for drying outin muddy creaks where there is uncertainty about what lies beneath.

Examples: RM Yachts, Moody (some versions), Westerly (some versions) etc

RM 13.50 with bilge keels

Canting keel

A much more recent development. Found almost exclusively on racing yachts, such as those competing in the Volvo Ocean Race or Vendee Globe. Canting keels provide considerably more righting moment as the keel moves out to the windward-side of the boat while using less weight. The horizontal distance from the weight to the pivot is increased, which generates a larger righting moment.

Examples: Open 60’s, Volvo 70, Marten 65

  Volvo 70 canting keel

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