monohull to trimaran conversion

Converting a Monohull to a Trimaran  .. and what to consider.

I have an old monohull with sound structure that I now plan to convert to a trimaran.  What aspects should I consider when selecting suitable amas (floats) and what sort of performance might I expect ?    Mark, New Zealand

This is perhaps the most frequent question I've received over the last 10 years of running this Q&A service.  Here is some personal advice on the subject.

First, the owner must accept that the performance of the final boat will not match that of a custom-designed trimaran.  That center hull will be proportionally wider at the waterline than would be a trimaran vaka (main hull), and even the keel profile will typically be far more 'banana' shape with the result that there's less directional stability and more pitching.   Water surface will also be higher and the monohull will not be at ease being pushed much faster, so main hull waves will limit maximum speed compared to that of an equivalent length trimaran.    Upwind performance will vary a lot, depending on the final choice of amas, how broad is the central hull and the windage it creates.  The final converted boat will also be unlikely to garner much value so one cannot expect the same resale value as for a dedicated trimaran design. 

But if the owner/builder can accept all the above, it IS possible to create a comfortable trimaran that heels less than it did as a monohull and also sail, at least in some directions, a little faster than it once did at the limiting hull speed of the original boat.

Here are some steps you will need to consider.

Conversion work on the Main Hull :  Choice of Amas & Akas :  Sail plan :  and Rudders & Foils ... so let's look into each. 

Ideally, the Main Hull (Length 'L') should ideally be relatively narrow and light, and permit the keel to be readily removed as this will no longer be required for stability.     However, the trimaran will still need some lateral resistance so a centerboard of some type will be required.   (my article on Foils might help on this).   Obviously, the hull should be faired and closed-in the neatest way and with any lost strength compensated with the addition of adequate glass or carbon fiber to the shell laminate.

If the hull is very rounded, the low speed performance should be fine as long as the amas are not set too deep relative to the main hull (see below and read about dihedral here ) .... but if the main hull is too vee'd, expect it to be wet when pushed ..., or if the keel profile is too banana shaped, expect the boat to pitch considerably in waves and be more limited in speed.

You will need to choose the position of the cross beams, and the structure and arrangement of both the main hull and that of the chosen amas must be part of this decision.   They should be a reasonable distance apart (say 35-45% of the main hull length) to keep the stresses acceptable in the connections.

Re the choice of Amas , this will depend on the type of sailing you enjoy and seek.     Smaller amas (say 0.75L) will support less sail area but will allow the boat to heel more enabling wind to escape, as well as needing less strength from their akas      If you are prepared to ease off the sail as soon as the leeward ama goes 80% under, you will stay safe and be unlikely to capsize.   However, if you want more power, amas up to 100%L and with buoyancy over 100% of the total weight will offer more power and add more speed potential, as long as the akas and their attachment to the main hull are designed with adequate strength.   See this article on Aka design .    As noted, I typically advise that the load on the forward aka beam end be taken as the maximum buoyancy offered by the ama, even if this includes a margin for most normal sailing needs.

One aspect that I consider important that others may not, is that I would personally seek a visual match of the chosen amas with the main hull.   A main hull with a large bow overhang can look ungainly with amas that have more vertical stems, even though the boat may still sail acceptably.     From the performance point of view, amas that have straighter keels (like the newer beach cats, compared to the earlier H14 and H16) work better and help to reduce pitching.   Ideally, you want the center of the ama volume (the center of buoyancy) to be well forward as this helps to prevent pitch-poling and if different from the main hull, can also help to reduce pitching.    Positioning the ama bow well forward will also help to resist pitch-poling.   

In profile, unless trials prove otherwise, it's generally a fair initial assumption to place the sheer line of the ama parallel to the sheer line of the main hull.   In terms of the ama height, this is more determined by the location of the ama keel relative to the waterline.  If the ama keel is placed slightly below the static waterline, the stability of the ama acts more quickly and the boat will therefore feel more stable.   But the additional ama drag can slow the boat in light winds.   Contrarily, if the ama keel is positioned to be above the water-surface, the boat will be fast in light winds but will feel unsettlingly jittery until it heels enough to put one ama a few centimeter's into the water.  The compromise I most often aim for myself, is to have the ama keels 'just' kissing the static water surface with the main hull fairly lightly loaded.   Ultimately it's for each designer/builder to make their choice as each decision will be a compromise.    Light racing boats may have amas a little higher, but loaded cruising boats will almost always have their ama keels underwater.    Boats with higher amas (like the Buccaneers of Lock Crowther) will allow the boats to heel much more before the amas 'get-to-work'.   While this heeling will lower the sail power that can be applied to the boat to drive it faster, it also unloads excessive wind load from the sails that can save it from capsize. With fast boats that have their amas at the waterlevel, the best way to avoid capsize will generally be to reduce sail ..., and/or to have some semi-automatic way to release the mainsheet .. but that's a whole new subject ;)

The actual Aka (or cross beam) could be made from a pipe or mast section (aluminum or carbon fiber), or from fabricated wood beams.  But either way, the deck edge of the main hull will need to be reinforced over a reasonable distance to adequately spread this upwards load, down into the side of the main hull.

The Sail Plan could either be from the original main hull ..., or even from the boat donating its amas ... such as a beach cat.

But remember that 1) sails on a multihull generally need to be cut a little flatter than for a monohull and 2) the stability of a trimaran will increase the load on both the mast and sails, so if coming from a beach cat, it's recommended to cut down its mast length to not exceed 1.35L of the original beach-cat length .... or if from the main hull, consider a max of 1.25L of the main hull.   Of course, if you have the means to calculate the actual mast strength relative to the boat's stability, then you may be able to slightly exceed these figures, but without that, I would recommend to stay within them.

The final thing noted above are the Foils .   Some means to limit lateral sliding of the boat will be required, and this need will be more with a banana-profile hull than with one that has a deep forefoot and relatively straight keel.  Some guidance on a suitable area will be found here.     The rudder of the original hull will likely be more than adequate, but you may want to modify its profile to bring a little area forward of the rudder-stock (pivot) to lighten its feel.  Just 10-12% of the total area forward of the pivot can make a significant difference in feel and the pleasure of sailing.

Good luck with your conversion if you go this route .. and feel invited to send me some pics that I can then add here if they show something of pertinent interest.

"New articles, comments and references will be added periodically as new questions are answered and other info comes in relative to this subject, so you're invited to revisit and participate." —webmaster

"See the Copyright Information & Legal Disclaimer page for copyright info and use of ANY part of this text or article"

Another Look at the Tricote Trimaran

by Small Tri Guy | Nov 30, 2012 | Self-built Small Trimarans , Small Tri Info - All , Small Trimaran Videos | 26 comments

We first featured the Tricote trimaran on this post . This trailerable tri is another successful example of a “monohull to trimaran” conversion.

The pics below are linked to directly from the Tricote website . And there are many more great photos there too, so you are encouraged you to go there and peruse those pages.

A new video featuring the Tricote under sail has just been released on this page at the Tricote website . ( Just be aware that it may take a minute or two to open up in web browsers for viewing .)

This video is a little bit different from most vids because there are some great angle shots at various points of the boat as it moves through the water. It’s kinda neat … of you don’t get dizzy by this type of videography :-) Update 12/10/12: The video on the above page, plus a 2nd one, are now on YouTube, which means I’ve been able to upload them here on this page. ( They appear at the end of the pictures just below ).

Here are some still images to get the creative juices flowing in some sailors who think about converting the right kind of monohull into a multihull …

26 Comments

Another example of a very beam-y main hull performing well…I contend that this boat and the J-24 conversion manage this because (besides being very light to start with) they have very shallow draft, where most traditional long/skinny hulls used on tris use a relatively deeper draft/length to get the buoyancy they need to work.

When you look at the underwater cross section and wetted surface of both types, wide/shallow and narrow/deep can be identical. As you get smaller, long/skinny eventually requires so much draft to develop volume that wetted surface skyrockets and you end up with a giant keel. Go the other direction and you get a surfboard.

Tris get away with long/skinny hulls because the traditional stability rules that make them unsuitable for many uses as monohulls simply don’t apply…and for boats that are paddled or use small rigs or live in perpetual light air conditions they offer great performance with little power input…but there’s other ways to skin a cat and the flatter wide hulls can work just fine too.

What I really like about this one is how well it all works together lines-wise…it doesn’t look home made at all and is as traditionally pretty as any other little pocket cruiser of that type, and the extra hulls only complement the graceful sweeping look of it all.

In case anyone is interested in the stats on the donor boat-

http://sailboatdata.com/viewrecord.asp?class_id=5714

right at 900 lbs with the ballast removed, and with the keel section gone (and 25% lighter) maybe 1′ draft at the deepest point, tapering to nearly nothing at the ends.

Beam/length ratios are important, but so is beam to *draft*…and the sectional shapes the ratio creates

if you look at something like a canoe or kayak it might be 18″ wide at the WL and draw 6″ loaded for a 3:1 ratio, which is great with the right length and if you don’t need lots of initial stability.

But a 3:1 ratio based on the main hull beam here would be over two feet deep; instead it’s half that. Yes, you are pushing that wide beam dimension through the water, but only a very shallow slice compared to the 3:1 section.

Hi Ian, You’ve probably already seen the “Soling trimaran” here at http://smalltrimaran.co.uk/?p=2144

It too is a mono to tri conversion. I link to the website for this boat which still features old video clips of this one sailing. You can check a few out at http://members.aon.at/trimaran/engl/eVideosite.htm

I have seen that boat and it’s another good example…they look very long and skinny compared to something like a modern racing skiff/dinghy and have a very narrow transom by comparison to newer concepts, but still the Soling is pretty wide for its type at 6’3″ on a 20′ waterline and very shallow hull draft…and it is also pretty light with 1/3 of the overall weight being ballast.

Here’s another one, this time a Venture 21-

http://www.boatdesign.net/forums/attachments/multihulls/58648d1310170498-hobie-j24-trimaran-conversion-wisper1.jpg

http://www.boatdesign.net/forums/attachments/multihulls/58652d1310170556-hobie-j24-trimaran-conversion-whisper5.jpg

-those boats did alright in lighter airs but were very tender and*very* lightly built and were nothing to write home about as well founded yachts, but I could see one doing well as a trimaran if you did the engineering and fabrication right.

Great images. I am guessing the sailors who’ve done these types of conversions have a whole bunch of “on the water” time under their belt. I can’t imagine doing such a thing … at least not without many years of experience, with a proper understanding how sailing hulls interact with the water.

For a potentially fast open day boat, the Tempest class is a 20′-ish Olympic keelboat that would be ideal as well-

http://sailboatdata.com/viewrecord.asp?class_id=3043

“Due to the planing hull shape and large sailplan, the Tempest is remarkably fast when sailing on a reach, and speeds in excess of 15 kts are not uncommon in moderate winds”

http://en.wikipedia.org/wiki/Tempest_%28keelboat%29

-and that’s before swapping out the 43% of its total displacement that is dead ballast weight and all the trapeze gear for a couple of amas and connections that won’t come close to weighing the 440 lbs. the ballast did.

Combine one of those and something like a NACRA cat and you’d have a very fast and relatively seakindly and predictable boat.

The Flying Fifteen is another similar design, and there’s tons of non ballasted dinghys that could be used as well for smaller boats.

One real classic that couldn’t help but have been an influence on Norm Cross and his contemporaries doing early ply tri’s is the Lightning, which is about as perfect as this type of boat gets-

http://www.lightningclass.org/marketplace/classifieds/2012/14844.asp

-that would be a great hull to make into a tri that was a bit more sensible and comfortable than a low freeboard dinghy, but could still be made to perform incredibly well using amas instead of hiking and extra crew to keep it upright.

It’s already designed with no keel to remove, and also keep in mind that you might be able to get rid of the CB trunk and its weight as well by using an externally mounted trunk or leeboards…

which might help tune the lateral resistance as a tri too- one thing to keep in mind with any conversion is that the keel and rudder placement relative to the rig and amas is critical to keep things moving straight and safely, so don’t count on the dagger/centerboard being perfect as is.

Anyway, lots of boats are out there and plans as well…

OK, here’s a 20′ main hull and two 18′ amas in fiberglass, with two complete rigs, four sets of sails and three rudders and boards to work with (maybe sacrifice a mast extrusion for wider crossarms?), all for under $2K-

http://for-sale.yakaz.com/lightning-sailboat-for-sale#lo=4&docid=0003mcgn0rm02bou

http://www.sailingtexas.com/ssolcat18a.html

– sell off a couple of the sails and other extras and you could probably fund the whole project for the cost of the donor boats. Not bad for an all glass 20′ trimaran with a modern rig.

Hey, these are some great thoughts Ian. Some minds are really going to be rolling with this stuff now.

Thanks Joe…of course it’s easy to just say “put this with this” and the real world is a harsh mistress so my “design” is worth what you paid for it…but in the case of the Sol Cat I have sailed them and know their idiosyncracies and have some place to begin with as far as placing them…the bows are very fine and that would need to be taken into account, and the standard crossarm connections that are very far aft compared to other beach cats might need to have another one up front to keep everything flat/square.

You definitely need to know at least a little bit what to expect and why and most importantly be patient and expect unforseen issues, but it really doesn’t need to be any more technically demanding than building a decent garden shed or customizing a car.

BTW, another piece of the puzzle with the original “Tricote” donor boat that I just learned is that Lanaverre (a builder I’m not familiar with but evidently big in France) manufactured a number of high performance dinghys like 505s, Flying Dutchman and the Tempest keelboat as well, and so was familiar with doing light/strong boats that would be suited to trimaran use…

Lots of older FG boats that look like that one from that era were incredibly overbuilt since they really had no idea what they could get away with and generally built things to last…so lots of them are very heavy for their size and comparable to traditional plank on frame in that sense, but I’m guessing that a pioneering FG racing dinghy builder would have been a bit ahead of the curve as far as building light but strong and probably wouldn’t pick a dog of a hull even for their more conservative boats-

http://sailboatdata.com/view_builder.asp?builder_id=304

Upon further sleuthing, I discover that the designer of the Lanaverre 590 – Christian Maury- is the same guy who designed the 470, which is yet another great Olympic planing dinghy shape that would make a crazy fast trimaran-

http://www.youtube.com/watch?v=Amy7h9Jjfpc

he also designed the 420, the 470’s baby brother that also planes-

http://www.youtube.com/watch?v=BqxxxUnpL34

I should also give credit where it’s due and mention that the Lightning was designed by the great Olin Stephens of Sparkman and Stephens fame, who had his hand in some of the most gorgeous sailboat designs ever conceived-

http://en.wikipedia.org/wiki/Olin_Stephens

http://www.thegledaproject.com/wp-content/uploads/J5-Ranger.jpg

…this one like the Lightning is pretty much perfection, and the standard by which all other boats of its type are judged-

http://dorade.org/DoradeClassicBoatArticle.pdf

As Ian knows from our frequent emails, I’m on a fundamentally different page than him re the width of the center hull in a tri. I have heard too many bad stories about what happens when you try to “convert” a monohull onto a tri. Bottom line: It never seems to go very well. There’s a very solid reason why purpose built tris all have skinny vakas as well as skinny amas. It works better! Check out the current sailboat speed records – virtually all held by trimarans or by some other craft with a long skinny hull – and the conclusion is inevitable. Long and skinny works best! Not that there aren’t some very fast monohulls (Cheubs, Moths, Finns), but if it’s three hulls you want, why ignore the abundant evidence from every trimaran designer on the planet? Long, skinny hulls simply work best! – Frank

This talk about center hull form for a smaller trimaran reminds me of what Phil Bolger supposedly drew up … a couple renderings attributed to him can be seen at http://smalltrimaran.co.uk/?p=3428

The converted boats featured here seem to move along quite nicely and aren’t being manhandled due to improper design geometry and appear well founded…some are better matches of hulls and slicker in execution than others but one thing that I think isn’t being considered is that as far as western sail boat design goes, the abundant evidence from every monohull designer was that long and skinny was always “best” too, for a long, long time.

In some cases it still works best but there are all kinds of reasons for doing it, and reasons not to…there’s also the fact that in the big scheme of things, the long skinny ratio of polynesian hulls is as extreme as it gets…using that as an ideal really short changes a lot of monohulls that were really not much different dimensionally than many purpose built trimaran main hulls and may be far better suited to cruising demands than the long skinny tallish hulls with narrow ends that are the current state of the art for big racing tris, or the deeper polynesian inspired hulls.

If you want long and skinny, monohulls are probably the best place to look for adaptable shapes, because the traditional long skinny low volume polynesian style hull doesn’t give much room to modify it to some purpose…they are already at their low end limit for volume and so all you can do is make them longer and longer or do chines or not. Anything else and it isn’t a long skinny hull anymore.

But I think you’ve mentioned something about a b/l ratio of 6:1 being as low as you’d want to go, and if so i think you are being pretty conservative in what you consider too wide to work as a tri…this boat is about 5.6:1 and very narrow-

http://www.asqma.com/yacht%20profiles/Scarlett%20O%27hara.html

The Hereschoff “Rozinante” canoe yawl is very fast and nimble to sail and is also very tender due to being a giant shallow canoe shape…it’s b/l ratio is 4.6:1 and it is not at all a fat boat-

http://www.sailboatlistings.com/sailimg/m/18702/main.jpg

The scow shape in the link Joe posted is another hull form that doesn’t look fast but can be…people see the bluff bow from above and the lack of a sharply vee’d entry and assume that it can’t go fast- but for many years it was scows that held all of the sailing speed records and the Fireball is a very fast small planing scow-

http://www.youtube.com/watch?v=XllmIHwO_7s

Of course that boat is a pig by comparison at 3.7:1 b/l ratio but manages to plane to weather at trimaran like speeds already…I still haven’t seen anything that would cause that boat or something similar to not still do so using a properly designed ama to stabilize it instead of trapezes…all the claims that it won’t work seem to center on notions that such a boat could not plane, but I have yet to see one built let alone any documentation of its failure so as far as I am concerned it isn’t settled by a long shot even if “every trimaran designer on the planet” agrees, which on a commercial level is about three dozen people doing the same basic designs over and over because that’s what people want.

I’m not ignoring the evidence that long skinny tris can and do work and can do it well, I’m just not buying the idea that there’s a ton of evidence that wider flatter hulls can’t work or are fundamentally flawed on a tri, when they work just fine all over the place under both sail and power and actually perform best when kept flat in a manner that trimarans do naturally and better than almost anything else.

Here’s a great example of a very fast planing tri that uses a fairly wide main hull-

http://www.youtube.com/watch?v=77rZsB4nvso

Note that a lot of the time it is just sailing like a planing dinghy and the amas only skip across the surface occasionally…they aren’t holding the thing upright at all times in anything like displacement mode and drag is minimal

Here’s another of the smaller version, going through a boat wake with ease and I guarantee, with a lot less hobby-horsing and water shipping aboard than a typical needle hulled high performance tri of similar dimensions – http://www.youtube.com/watch?v=-y24uoE7YjI

The Magnum trimaran is unique (as far as commercially-built small tris go) in that the designers seem to have in mind what you’re talking about Ian. The bottom on the main hull is relatively wide and flat. The boats are fast. The only thing that I remember reading a comment about (from online videos featuring Magnums) was that the shape lent itself to a bit more “rocker” at times. You can see the bottom of a Magnum on a trailer here… http://smalltrimaran.co.uk/wp-content/uploads/2012/12/magnum-tri-flat-bottom.jpg

Rocker certainly factors into how a long flat hull will perform both in a straight line and turning, and more rockered shapes tend to turn better at the expense of longitudinal stability and quickness to plane.

It’s one of the basic design factors involved in shaping surfboards and can be by far the most important element in how well they work, and oddly enough it is *more* tail rocker aft of the beam that makes them less likely to stuff the nose in, as that rocker induces a nose high trim as the board planes and squats on its tail. Intuition might tell you that a very high nose would be better, but that simply doesn’t work as that part of the board rarely gets in the water and once your trim is so nose down that it might matter, it’s too late.

Longboards with very long straight runs will begin planing on waves that are barely waves, long before anything else will…but once they are on plane the balance shifts radically and to keep one trimmed at speed you have to move very far forward to keep it going, which is the whole point of “hanging ten” and noseriding…

The drawback is that turning input from this position does little and the fin can pop out completely if you try to hard, so to turn you have to move aft and change the angle of attack, and to do tight turns you can stall the planing surface completely at a high angle of attack and let momentum carry you through as you pivot around.

I wish people who haven’t could experience the feeling of balancing a longboard at speed like this could do so…it’s really very enlightening as far as understanding how vastly different the forces at work are- as you move forward you can feel the power of your weight being turned into thrust by the leverage, as well as an increase in the forces that are holding the tail *down* to a degree that allows you to stand at the extreme nose end and still be moving straight and relatively level.

Those kinds of trim considerations need to be factored in if you want to have a successful planing boat of any kind and certainly present challenges to anyone trying to design a tri that would exploit those principles, but the fact is that traditional sailors are almost congenitally fearful of boats that require those kinds of active trim considerations to work.

They have a point when it comes to boats that are unsafe without constant attention and are unseaworthy, but then again it can be like the three wheeled ATV’s that were deemed unsafe as “inherently unstable” while motorcycles that have no inherent stability whatsoever are perfectly OK…trikes are not forgiving as far as bad design geometry and loading and panic steering inputs and require special knowledge to operate safely, but they are far more stable than the bikes that kids ride.

Boats are the same way, and tris have some unique characteristics that allow for some extreme design options when it comes to hull selection and placement and weight distribution, but you have to be cognizant of the trade offs and the critical aspects of how it will all interact with the operator and environment, and even extreme designs need to err to the side of safety and predictability if you are going to call yourself a real designer.

But the long skinny thing has to be viewed within the spectrum of *all* available forms and beam/length/draft ratios that exist and have their merits and elements that can be incorporated elsewhere…and on that scale, the extremely narrow displacement hulls preferred by many are ***extreme*** hull shapes that can have extreme reactions at speed just like the surfboard shape that you have to stand on the tip of to keep level as you apply more and more power.

Long skinny hulls driven fast get hinky in a seaway and so as the hulls got longer and bigger and faster they had to be made to operate submerged as they punch into any waves like an awl, which is one way of doing it…but the thing is that putting three of these hulls together does nothing to change their propensity to sail under when driven….broaching is another story and a tri will handle that better than the single skinny hull and mitigates many of the stability issues with long skinny hulls, *but* the deeper those skinny hulls are the worse the recovery and the more likely it is to trip.

In a situation like this a wide shallow hull will simply skid and the “best” hull shape for riding out huge seas would be something like a Frisbee or shallow saucer with no edges or depth to catch or turn it uncontrollably as it surfed and stalled. And of course the more saucer-like shapes of things like planing racing skiffs and powerboats offer high performance too, so it seems that there is a whole world of possibilities to design very capable fast trimarans that are seakindly and sporty…

The only thing really extreme about the Magnum is that they dared to not follow the “long and skinny is best” rule…the amas don’t even appear to be optimized to plane and yet there it goes on it’s fat wide hull planing along in a fresh breeze under a reefed main, and handling chop predictably like a plain vanilla monohull because that’s pretty much what the main hull is.

When I interviewed Magnum’s UK distributor he made it a point to explain that the designers chose to go the other way from what most designers were doing. (Instead of a long and skinny vaka hull bottom they wanted the relatively wider, flatter one). Their success shows that the concept can work well on a small tri … other factors being taken into account for, of course.

I’m surprised no one mentioned the old British “plank on edge” designs that ultimately proved to be rather poor monohull sea boats. With sea states being what they are, so variable, unless you design a tri for a particular set of sea states, probably fairly narrow set of conditions (like the cats currently used in the America’s Cup Races ( watched a while ago), a cruising tri will need to be used in all kinds of conditions, and designed to get he most out of the desired characteristics. Roomyness (as the old Horstmans were “accused” of having at the expense of something else), or higher speed like the Newick cruisers were, though at the expense of roomier interiors for their size and length. Flatter water usually lets flatter hulls move nicely, bumpier water usually needs a less flat, more “veed” or narrower truncated vee or rounded bottom to move well without wave interference slowing the boat too much. The bow for any design has a large part in how the water separates and starts flowing around and and under the hull(s) too, so there’s so much to consider for each type: Racing; Racer/cruiser; Cruiser. Any can be a daysailor pretty much as well, though the crew compliment will matter depending on the hull and other design considerations of course. Ultimately, proven designs like Cross, Horstman, Brown, Crowther, etc. and that have excellent safety records show what can be done with the various parameters used in a design.

One thing that plays a huge role in how well a long skinny hull will work is the overall length of the boat, and the fact that there is a minimum amount of volume necessary to float an occupant and have enough freeboard to provide a level of safety underway and in waves…after a certain point you simply cannot build a long skinny hull with enough volume to not just sink when you get aboard, and for a 10:1 ratio hull with fine entry and exit it gets really critical around 10’…any smaller and you’ll have a very wet and unstable boat with little reserve freeboard no matter how wide you space the hulls.

That’s the extreme end of “small” for any boat, but even a 20′ boat with long skinny hulls will have a restricted ability to handle large payloads, and the placement of any loads including people will be far more critical to safe operation than something with wider hulls, or even just hulls that flare out at strategic points above the design waterline to provide flotation/lift and stability in extreme out of trim or big wave conditions.

At the types of speeds such a boat is capable of in the kinds of winds that make those issues a real problem, there’s all kinds of ways to deal with them short of shoving the boat halfway underwater every time you encounter a wave, like riding over them…and the fact is that even if you want to go that route, wave piercing hull forms don’t have to be tall and narrow at all- surfers use the wave piercing abilities of flat hull shapes to great advantage almost every time they go out-

http://www.youtube.com/watch?v=X3tMc1FTTmM

-that’s an extreme example using high angles of attack, but it’s still a low volume wave piercing shape efficient enough to get itself and a very high drag human through very large waves relative to its size in a manner that actually creates forward thrust, all for the cost of weighting/orienting it properly at the right time.

Applied to a trimaran, very flat surfboard-like amas with springy rear crossarms could actually take the energy developed by heeling/submerging and being pressed upward by waves and the like (including the main hull’s bow wave), store it in those springs, and then release it a way that would vector that energy into forward thrust, much the same way that a surfer pumps a short board-

http://www.youtube.com/watch?v=ZVB2VhcSdpI

-interesting to note that the shortboard “hop” is very similar to the bouncing motion of extreme planing skiffs and that the tradeoff for the easy speed of the longboard is the ability to turn quickly, while the short board can turn on a dime but has little inertia to keep it gliding and needs help in smaller surf.

Great comment on the “plank on edge” boats, which were rules-based aberrations like the IMOCA swing keelers, bulbous reared IOR boats with massive tumblehome, and all manner of oddities that could do good things but often developed fatal flaws as everyone followed each other down the next rabbit hole…there’s a really good article about the type and its failings here-

http://intheboatshed.net/2012/02/18/jeff-stobbes-striking-and-beautiful-victorian-style-plank-on-edge-yacht/

-and more here, that goes into related rule based designs and progressions in the “common knowledge” about what makes a fast sail boat, and how many “fast” boats aren’t-

http://www.storerboatplans.com/wp/design/2469/

BTW, don’t miss the comments sections, there’s other posts that go into a lot of good detail on the subject of both truly fast designs and reactions to them…

One boat mentioned in that article should be of particular interest: the original maxi sled Infidel/Ragtime…as radical as could be when launched, dismissed as dangerous, silly and eventually ruled out of competition for being too successful…but still afloat and competitive nearly half a century later after countless offshore passages where she was driven hard and dominated over larger boats…modified and upgraded to be sure, but still riding the same dirt simple hard chine hull that blends from a narrow deep vee’d forward section to a nearly flat surfboard shape astern, and looking for all the world like a maxi tri looking to trade in that lead bulb for a pair of amas-

http://www.sail-world.com/USA/index.cfm?SEID=2&Nid=28564&SRCID=0&ntid=10&tickeruid=0&tickerCID=0

http://www.boatdesign.net/forums/attachments/sailboats/30205d1237850991-ragtime-lines-maybe-ragtime.jpg

Not so coincidentally, Ragtime’s designer John Spencer was also the designer of the Cherub dinghy Frank mentioned as well as other fast planing monohulls, and Ragtime is obviously highly influenced by fast planing dinghy and surfboard principles. At launch it was heavy compared to the same type of boat today and so didn’t plane so much as surf for **very** extended periods, and could do it pretty consistently in the low-mid 20 kt. range with recorded bursts up to 30, all back in the mid 1960’s long before tris were doing that, or even being built at that size…it still does-

http://www.youtube.com/watch?v=hoyLOWEKs1A

Point being that there doesn’t have to be a solid dividing line between long/skinny and flat/planing hulls, except that for the purpose of a *small* trimaran, to have the ability to plane or surf consistently you need the beam to develop any planing surface because you’ll never get enough in a long/skinny hull unless it is something like a surfboard, which as has been pointed out has very definite drawbacks in a seaway.

Ragtime gets around it by being a narrow vee up front , and a surfboard/powerboat in back…she’s a bit slappy at times like any simple hard chined boat and can get wet when driven to weather, but a lot of that has to do with heeling and the big rig needed to get all that lead moving and could no doubt be evened out in a trimaran version that had a significant percentage of the overall weight removed- close to half the displacement, if I remember correctly.

65′ LOA and 11′ beam for a b/l ratio of 5.9…not a fat boat at all, but also not shaped like a Polynesian ocean catamaran hull… it is shaped more like a Polynesian planing hull- the surfboard- just modified for oceangoing to let the bow cut through the water rather than slap down on it, and given some freeboard .

It’s a well proven design concept – the Cherub is from the early 50’s- that can be shortened considerably and will still work, but really needs to be sailed as flat as possible which is the biggest drawback using this type of hull as a mono- you either need ballast in larger boats or trapezes/wing seats/hiking straps in smaller ones- racing scow sailors sometimes stand on the windward bilge boards for leverage…but heeling flat hulled monos *really* slows them down and causes them to ship water instead of riding over it, and the shorter/beamier they are the weirder they get when heeled…but even the short beamy ones can develop gobs of power when kept level.

now if only there was some type of sailboat platform that had high initial stability and operated normally without much heeling…then a wide planing hull used as part of it would be able to sail flat where it performs best most all of the time…and with the high initial stability it could even do it without any ballast…. if only…

Seriously though- long skinny hulls like kayaks in the 8:1 range and more extreme hulls seen on tris and cats can *only* be sailed safely with powerful sails if they have some kind of stabilization, and the low volume restricts the ability to do it with ballast. Multihull platforms allow extremely narrow for their length hulls that would be mostly useless otherwise to be useful, and what advantages may lie in those hulls can then be exploited…which is a great thing and you can certainly choose to never venture away from those hulls and do just fine.

All I’m saying is that the same thing can be done with other hull forms using the trimaran’s unique geometry and other qualities to exploit good things and mitigate bad ones, and it is a never ending source of puzzlement to me that people would not only say this can’t be, but would make that claim over the suggestion of using hull types that *can* function as boats in their own right and were proven decades ago, that would only be improved by losing ballast weight and being kept level by a tri platform.

I totally get that there might be some qualities to the ride or seahandling of such a boat that might make it unsuitable for some people’s style of sailing or location or other factors, and I respect their concerns and ultimate choices and would very likely make the same ones were I in their shoes…but the biggest advantage of multihulls is their adaptability and if the “you can’t do that” and “monohulls are best” reactions to the early days of modern multihull development had been left unchallenged, we wouldn’t even be having this discussion.

Amazing discussion guys! And amazing references for additional info. I once had an email exchange with Michael Storer about what would make for an ideal rig for a certain small trimaran design. He is a very, very smart guy. He blew me away with his knowledge.

Hello, Sorry for my poor english. I’m the builder of Tricote and i’m proud to see an other article about my boat. And discussions about this article are very interesting. It’s a little difficult for me to read and understand all technicals words, but with Google translate, it’s long but very interesting. If i can answer to any question you have about Tricote, don’t hesitate. Thank you.

I am seriously considering converting my ‘Pandora international’ into a tri using hobie 18 ama’s. I intend adopting the same beam configuration as the ‘Tricote’ boat. Do you think the Pandora would make a good main hull?

All the best!

Hi Mark, It might work. If I were you, I’d simply invest a few bucks and speak to a naval architect like John Marples (marplesmarine AT gmail DOT com) and get his take on things. It would be worth it to pay him for an hour of his time to do some consulting with you. Send him the Tricote links from this website with pics of the Pandora before your scheduled phone appointment in order to give him time to access things. That will give him the info he needs so you can receive a top notch consultation. In my opinion, doing that would be well worth it in order to either move forward successfully … OR … stay away from making a bad investment of time and money to create a conversion that won’t perform well.

Thanks for your input, I will drop him a line to see what he thinks.

All the best.

UR more than welcome Mark :-) John’s hourly rate is so reasonable that I wouldn’t hesitate to get his input on your idea before pouring lots of time/money into it. He is among the most knowledgeable out there when it comes to multihulls too.

Submit a Comment

Your email address will not be published. Required fields are marked *

Notify me of followup comments via e-mail. You can also subscribe without commenting.

Blog Post Categories

• Production/Commercial Small Trimarans (291)
• Self-built Small Trimarans (678)
• Small Trimaran Audios (30)
• Small Trimaran Videos (289)
• Trimaran Design, Rigging, Construction Info/Links (222)
• Contact “Small Tri Guy”

Why Choose a Trimaran over a Monohull?

Why choose a trimaran over a monohull:.

Corsair Trimarans provide safe sailing excitement for the whole family

The first item on this list might surprise you.  But trimarans are exceedingly safe – in fact many, including all of the Corsair trimarans , are virtually unsinkable.  They’re foam cored, and relative to the displacement of the boat, the buoyancy of the materials is very high. Even were a Corsair to be fairly well destroyed (think passenger ferry) the remaining debris would remain at the surface providing something to cling onto. But there are some other interesting stats as well.  Kids love trimarans – the nets make for great fun.  And were they to fall into the water its reassuring that there are so many places for a person (or child) overboard to grab onto – see the net lines and the beams themselves in the picture to the right.  There are also good places at the main transom to haul out a wet, heavy, miniature crewmember.

No gimmicks.  Trimarans simply deliver stunning speed without foils, wings or electronic aids. Speed might have slipped from number 1 factor to number 2 in recent years – and given the advent of foiling monohulls you might think that’s fitting.  But consider the costs involved in foiling monohulls and you’ll quickly find that Corsair trimarans have a far greater dollar-to-knot ratio. Operationally, trimarans are now seen as almost conventional in high-speed terms.  So you can clock up 20-knot plus speeds with a boat that has a 35-year track record of success and safety, and without the need for professional crew.

For a trimaran, this counts as “heeling”

While you, the reader are no doubt the hardiest of sailors, there’s also no doubt that not everybody you sail with will be! Corsair trimarans, and most others, have a max heel angle of 12-14 degrees depending on the model.  That’s “flat sailing” in monohull terms.  And it means that rudders and daggerboards keep a reassuring grip and the speed therefore feels more effortless on the helm.  That surefootedness transfers over to your crew – they’ll detect the confidence in the boat and the skipper.

Small Marina Footprint

Fold up and take only a small marina berth or land space

To achieve anything like the speed, and just a bit of the stability and comfort underway, you’d need a relatively large monohull by comparison.  But due to the folding mechanism, a Corsair trimaran keeps a very modest marina footprint.   Better still, they can be lifted (when folded) and are therefore easy to keep ashore.  Want to keep your boat in the water but worried about growth on the floats/pontoons?  Anti-fouling wraps from 3M are available from Corsair dealers – remarkably long lived, these are easily replaceable, and maintain a very quick surface.  Boat bags, which keep growth away from the floats and main hull, are available for mooring and marina use.

Above Deck Space

Check out the huge unfolded beam of the 24-ft Corsair 760

Anyone with children will immediately identify with this one – Corsairs are fantastic for their wingnet and bownet space.  When unfolded, the huge beam provides pound-for-pound the best boating platform around.  The nets are often used as sleeping hammocks in extremely hot climates – not just for an afternoon nap, but actually during the night.  And most trimarans can be fitted with a bimini, sail shade, or canopee when the sun is strong.

Trimarans are Synonymous with Trailerability

The new Corsair 880 Trimaran will be the Ultimate Trailer-sailer

In the next article, we’re taking a deeper look at trailering trimarans through an interview with the undisputed supremo in trailering tri’s – our very own dealer Werner Stolz from Germany.  Trailerability is absolutely central to creating a new holiday experience every year, and for the racers it opens up a whole new world of high speed multihull regattas.  That’s why Corsair trimarans are built light – of course it improves your sailing speed, but it also keeps your trailering weight down and reduce road risk.  And that’s why the floats fold underneath – so your boat doesn’t get longer on the trailer when folded.  For those who don’t want to commit to the same sailing grounds every year there’s no better solution than a Corsair folding trimaran.

Trimaran docking made easy

Corsair 28R won third place in Kieler Woche 2019

Corsair 880 design news

Share This Story, Choose Your Platform!

Related posts.

Corsair Regionals 2022 Recap

Corsair & Seawind Pittwater Regatta 2022

Corsair 880 Trimaran 2021 Review by SAIL Magazine

Seeing Triple – Multihull Trimarans Redefine Sailing With Speed & Agility

The current situation at Corsair Marine

• Subscribe Now
• Digital Editions

The best of both worlds? Introducing the world’s first trimonoran Project Escalade

• Superyachts
• Top stories

A radical new foiling hull design claims to combine the efficiency of a trimaran with the space of a monohull — Hugo Andreae takes a look at the world’s first trimonoran motoryacht.

Award-winning Turkish yacht designer Baran Akalin has combined forces with Dutch engineer G. Jelle Bilkert to create what they describe as the world’s first ‘trimonoran’.  As the name suggests it is based on a ground-breaking new hull design that claims to offer the efficiency and stability of a trimaran with the speed and volume of a monohull.

Instead of three slender vertical hulls linked by spars or a beamy main deck, the two outer hulls fan out at an angle from the central hull like the segments of an orange. These are linked below the waterline with hydrofoils to create the necessary lift for planing without the associated drag and unforgiving ride of a big, beamy monohull.

The idea was originally drafted by Dutch naval architect G. Jelle Bilkert some time ago but has now been refined, developed and tank tested with the aid of Dutch government funding into a fully patented production concept by Dutch company AnwigemA BV. Budding Turkish yacht designer Baran Akalin, who won a design award last year for his futuristic steampunk superyacht concept , saw its potential as the basis and has further developed the idea into a striking new luxury motoryacht concept named Escalade.

Tank testing of the scale model proved its potential

Fast and efficient

The benefits of this new low drag design are said to include speed gains of up to 30% over a conventional monohull, excellent stability both under way and at rest, large deck and hull spaces and superior fuel efficiency at cruising speeds leading to a greater range.

Recommended videos for you

The principal is much the same as a trimaran in as far as the slender central hull generates less drag than a single beamy monohull design and slices cleanly through waves for a softer more efficient ride. The two outer hulls then provide the lateral stability as well as the extra volume and deck space needed to house the accommodation.

However, unlike a conventional multihull, it doesn’t come with the penalty of an excessively wide beam that makes it hard to fit into marina berths, nor the small planing surfaces that require huge amounts of power to generate enough lift to make it plane.

Article continues below…

Steampunk superyacht takes yacht design back to the future

Leen 72 first look: Cutting-edge trimaran launched by Neel Yachts

The key to this new trimonoran design is the addition of two foils linking the front and stern sections of the outer hulls. These not only provide lift but also reduce drag to enable the kind of planing speeds not normally possible with this size and style of yacht. Another break from tradition is the adoption of a hydraulic link to transfer power between the engines and the propellers rather than a conventional shaft.

This allows the engines to be positioned amidships to keep the weight as low and central as possible while the propellers are mounted on the aft foil to keep them immersed at all times. The only physical link between the two are the high pressure hoses which feed hydraulic fluid from the main engines to the small hydraulic motors and shafts in the foil. Sealegs amphibious boats use a similar system to feed hydraulic power from the petrol generator mounted under the helm seat to the folding wheels on the transom.

Size not compromise

Akalin’s current design for Escalade is based on an LOA of 82ft (25m) with a beam of 32ft 8in (10m). This is almost double the width of a comparable monohull such as the Princess 82 (18ft 10in) but still usefully slimmer than a similar length of powercat such as the Sunreef Power 80 (39ft 4in).

Vast main deck makes the most of its 32ft beam with central seating on a raised plinth

This length-to-beam ratio creates enough volume on the lower decks for four cabins and four bathrooms including a large master suite in the bow and an additional two-person crew cabin. However, the big wins are on the main and flybridge decks, both of which benefit from the extra floor space enabled by that 32ft beam.

The main deck incorporates a large open plan living area with a galley on the starboard side and a lounge area to port, in the middle of the yacht on a slightly raised plinth is a central seating and dining area with uninterrupted views out both sides. Doors out to the side decks as well as the cockpit encourage an easy flow of people and air through the yacht. The styling of the interior is the work of British designer Celia Sawyer.

Access to the flybridge is via a central staircase which passes under a glass-bottomed jacuzzi that allows light to filter down into the cockpit below as well as a unique view for its occupants of the wake trailing out behind. Multiple sunpads on the flybridge, in the aft cockpit and on the foredeck ensure it’s every bit as luxurious as a conventional monohull while its futuristic looks are a far cry from the rather dumpy looks of some multihull designs.

Although only a concept at this stage Akalin is confident Escalade could be turned into a viable production or semi-custom superyacht at a price that would allow it to compete with monohulls of similar volume.

First published in the October 2020 issue of Motor Boat & Yachting.

Project Escalade features a radical new trimonoran hull

Designer baran akalin penned its futuristic lines, the three hulls are linked by foils at the bow and stern, 16 of the best must-see new boat launches at cannes boat show, new boats at southampton boat show: absolute navetta 48, watch: prestige f5.7 sea trial – exclusive drive of new £1.2m prestige, latest videos, watch: beneteau swift trawler 54 sea trial – £1.4m cruiser is the ultimate home, watch: parker sorrento sea trial: 50-knot cruiser with a killer aft cabin, watch: virtue v10 sea trial: €272k weekender, how to mark your anchor chain: 6 top tips from our expert.

Me and My Six Imaginary Friends: The Practicalities of Yacht Layouts

Smooth Sailing: Pros and Cons of a SWATH Vessel

• 8200 Fluids
• 8450 Fluid Loads
• 8600 Arrangements
• aker arctic trimaran
• deadweight coefficient
• littoral combat ship
• trimaran icebreaker
• triton trimaran

Why You Want a Trimaran: Pros and Cons of a Trimaran

Three hulls are better than one!  That would be the adage of the trimaran.  It consists of one central hull with two smaller side hulls, called amas.  The average person conceives of the trimaran as something even more extreme than catamarans.  Lighter weight, higher speed, more specialized.  The opposite is actually true; trimarans fill an excellent transition role between monohulls and catamaran.  Recognize the potential applications by understanding the strengths and weakness of the trimaran hullform.

1.0 What Makes a Trimaran

When you seek trimarans, envision stability.  A conventional monohull must balance conflicting needs of resistance and stability.  You want a narrow skinny hull to reduce resistance (and fuel consumption).  But you need a wide hull to maintain vessel stability and keep the ship upright.  The trimaran separates these two design requirements.

In a trimaran, the central hull provides most of the ship buoyancy (90-95% usually).  It does this with a long, narrow hull.  And then the outer hulls, called amas, provide the stability.  This arrangement allows incredible flexibility in the hull design.  Due to the wide separation between hulls, it requires very little buoyancy in the amas to keep the trimaran stable.  That is why many trimarans barely have their amas in the water.  Compare the relative size of the amas vs the main hull in Figure 1‑1.  The amas are just there for stability.

2.0 Advantages

The trimaran offers several capabilities to bridge the gap between monohulls and catamarans:

• Excellent for high speed
• Moderate weight carrying capacity
• Good seakeeping capability
• Larger available deck area
• Moderate space below the main deck

Another advantage is the design of the cross deck (Figure 2‑1) between the main hull and amas.  On a catamaran, this cross deck bridges a large empty gap.  Large gaps add complexity to the engineering and require stronger structures.  We don’t like that.  Stronger structures mean more weight and higher costs.  But the trimaran’s cross deck is much smaller.  It requires less of a gap between hulls, and it does not extend for the entire ship length.  Longitudinal bending is less of a concern for the cross deck.  This greatly simplifies the design of that cross deck, giving us many advantages:

• Heavier loads can be carried on the cross deck
• Less structural weight required for the cross deck
• Deadweight coefficients closer to monohulls

The long length of the center hull also offers great advantages for seakeeping.  This length greatly reduces pitch motions in a wave, and the narrow center hull reduces chances of slamming.  To improve things even more, the side amas reduce roll motions.  They add stiffness to prevent large roll motions.  But they also act to reduce roll accelerations.  All together, trimarans make for gentle seakeeping.

The trimaran offers major advantages for damage survival.  The side amas provide excellent protection to the center hull, which military designers find especially useful.  But the cross deck also helps with damage survival by containing massive reserve buoyancy.  Imagine a damage situation where the ship sinks down to its cross deck.  On a monohull, that would be game over.  But on a trimaran, the cross deck suddenly becomes a barge, easily supporting the entire ship weight.  This reserve buoyancy provides extra peace of mind in yachting applications.

Speaking of peace of mind, let’s talk about a sudden loss of stability.  In catamarans, you lose stability once a single ama completely leaves the water.  Push a catamaran past that point, and stability is a losing battle.  A fact that scares many vessel operators.  Trimarans do not have this problem.  They get stability mainly from submerging the amas.  The center hull always stays in the water, and the leeward ama continues to submerge.  This creates a predictable increase in righting moment.  In normal cases, trimarans never experience the sudden loss of stability.

3.0 Disadvantages

The biggest disadvantage for trimarans is lack of experience.  There are few trimarans in military applications, and even less in commercial use.  That lack of exposure instills wariness in many operators.  I appreciate caution, but don’t let that stop you from realizing the benefits of a trimaran.

Trimarans do have a few genuine detractors.  Due to their complexity, they require some extra design effort.  The cross deck introduces a few extra ways to twist and bend the ship, and the engineers must check each of these extra scenarios.  Finite Element Analysis (FEA) is the ideal tool for this.

Don’t worry about the FEA bill.  You should expect a slight increase, but nothing huge.  FEA was already a part of the design process for normal monohulls.  Most ship designs already require FEA to consider global hull bending.  That means the hard part is already done.  Your engineer already had to build an FEA model of the hull.  With minimal effort, engineers can expand that model to account for the additional design scenarios of a trimaran.

Cost definitely factors into trimaran construction.  The cross deck and extra hulls do add extra steel to the design.  You have to pay for that extra steel as part of the build cost. (Figure 3‑1)  But don’t assume this drastically increases the total build cost.  Adding extra structure is far less expensive than adding extra machinery and power.

Consider the alternative to a trimaran:  an equivalent monohull.  For the monohull, we strip off the side amas and widen the center hull to maintain ship stability.  But bad news.  A wider hull requires a larger engine, and associated support machinery.  In general, the machinery accounts for approximately 50% of the total build cost.  The structure is only around 25-30% of the build cost. [3]  Adding larger machinery costs twice as much as adding extra structure.

4.0 Applications

You see trimarans most often in high speed vessels and the occasional military vessel.

• Car ferries
• Military ships

One of the first experimental military trimarans was the Triton, a steel vessel with a displacement exceeding 1000 MT. [3]  (Figure 4‑1)  These are not little vessels.

Don’t think of trimarans as an expensive hullform.  The prevalence of trimarans with expensive ships is mostly a coincidence.  Imagine if you wanted a high speed ship.  First step is pick a trimaran hullform.  But for high speed, you also build it out of aluminum and load it with powerful engines.  Those are all high priced decisions that get imposed on the trimaran hullform.  The hull shape does not drive the price tag, and trimarans are not limited to high speed.

Aker Arctic even investigated using trimarans as an icebreaking tug. (Figure 4‑2)  Aker found the trimaran configuration especially useful for cutting wide channels through the ice with less power.  Trimarans are just a hull configuration.  How you use the hull is up to you.

5.0 Conclusion

Don’t let the previous trimarans limit your imagination.  The trimaran hullform bridges the gap between monohulls and catamarans.  It offers some advantages of both deadweight capability and larger deck area.  Primarily, trimarans deliver ship stability in a very power efficient package.  What uses can you imagine with that flexibility?

6.0 References

Related posts

Figure 3-1: Icebreaker Healy [4]

Surviving the Arctic: Polar Class Icebreakers

Figure 2-1: Icebreaker Mackinaw in Sea Ice [3]

Ramming the Ice: Icebreaker Propulsion

How to Design a Ship

Stability Letters Explained

Yachting Monthly

• Digital edition

Wow, that was fast! Why trimarans are SO much fun to sail – and how to do it

• Theo Stocker
• February 13, 2024

For their size, trimarans can punch well above their weight in speed, cruising potential and fun. Monohull sailor Theo Stocker gets to grips with how to handle one

Humans tend to gravitate into tribes of like-minded enthusiasts, enjoying the encouragement, support and sense of identity, while often looking askance at others; sailors at motorboaters, cruising sailors at racers, monohull sailors at raft, I mean, multihull sailors, and everyone looks askance at jet-skiers.

Large cruising catamarans (40ft now counts as a small one) are a world apart from monohull sailing, but there’s a sub-tribe of sailors dedicated to life on three hulls and builders such as Dragonfly, Corsair, Farrier, and Astus give them plenty of choice.

I’ve been sailing a 22ft (7m) Astus 22.5 this season, with just enough space for a family of four and a minimum of creature comforts. Thanks to her VPLP-designed hulls and 650kg all-up weight, we can sail upwind at 7-plus knots and downwind at over 10 knots with ease, all on a roughly even keel, while the kids play Duplo down below. It can also be beached and is towable behind a car.

Having, it seems, caught the trimaran bug, I wanted to get better at sailing and handling the boat, but my monohull sailing experience and habits were proving something of a hindrance, so we sought advice from some existing trimaran owners, and well as the UK’s top multihull sailors.

Much of the advice will apply to all multihulls , whether two or three-hulled, while other parts are just for small trimarans. I also found that brushing-up some of my rusty dinghy sailing skills helped get my head around what we were trying to do.

To try out our expert tips we went out sailing to see what difference they made. On the day, we got a solid Force 4-5 southwesterly, averaging 16 knots, but fluctuating between 12 and 20 knots true.

Blasting about on a sporty trimaran is a whole world of fun, but is much calmer than it looks

Trimaran sail trim

One of the biggest differences between a cruising monohull and a multihull is how the mainsail is trimmed. Leech tension on a yacht is often largely controlled by the kicker and the backstay, while the mainsheet sheets the mainsail in and out, predominantly controlling the angle of the boom to the centreline, and there may be a short traveller.

On a mulithull, however, there’s more than enough space for a good, wide traveller. Those who sail on performance monohulls will also be used to this. The sail shape is mainly controlled by the mainsheet, and the traveller then moves the boom towards or away from the centreline.

This is exaggerated on a multihull which has wide shrouds, swept well aft with no backstay, making space for a powerful square-top mainsail with full-length battens. There’s no backstay to bend the mast and flatten what is anyway a pretty rigid mainsail.

The mainsheet purchase creates enough power to control the leech of the square-top mainsail

Depowering a trimaran

Sailing on a monohull, heel and weatherhelm and eventually a broach give loads of warning that you’re pushing too hard. With straight hulls and little heel, those warning signs don’t really apply to multihulls.

In reality, however, there are a host of warning signals that it’s time to back-off; they’re just a bit different. Even then, there’s still a large safety margin before you get close to danger.

By way of reassurance, with the boat powered up on a beat, Hein, from Boats on Wheels, the boat’s owner, stood on the leeward hull and lent on the shrouds. Even as his feet got wet and the wind gusted at the top of Force 4, the boat didn’t bat an eyelid, thanks to the huge buoyancy of the floats.

Even with a person on the leeward float the boat was extremely stable

On the water – sail trim

My first inclination was to point the boat as high upwind as possible, pin the sails in and go for height. Doing that resulted in a not-terrible boat speed of 5-6 knots and a good pointing angle.

Free off by a handful of degrees however, and ease the sails just a smidge, and the speed leapt up to 8-9 knots – over 50% more; a huge increase. So, don’t pinch. If you had a decent chartplotter on board, you could find your optimum speed to angle using velocity made good (VMG).

I was also tempted to pinch in the gusts, but it’s better to hold your course and let the speed increase until the main needs easing.

On the wind, it’s time to get the boat fully powered up

If that’s the case, drop the main down the traveller an inch or two or ease some twist into the mainsail and it makes all the difference in the world, but not so far that the top battens fall away and invert – that really isn’t fast. Push too hard and the boat will slow down, largely from the drag of submerging the leeward float and crossbeams. If you’re still overpowered and the main is luffing, it’s time to reef. Downwind is different, but we’ll get onto that later.

After we put a reef in the main, our boat speeds upwind remained largely the same, and the boat was much happier. I came away feeling reassured that even a little trimaran like this would be pretty difficult to capsize, and there were always plenty of warning signs telling me to take my foot off the pedal a little.

Article continues below…

Catamaran sailing skills: Mooring and anchoring a multihull

How do you make an average passage speed of 7 knots, fit in three double cabins and a huge saloon…

Monohull or multihull: which is best for blue water?

As former editor of Yachting World, David Glenn has plenty of experience of both monohull and multihull cruising. Here he…

Tacking and gybing a trimaran

Everyone knows that multihulls don’t tack as well as monohulls. Straight hulls and wide beam don’t lend themselves to turning, especially when coupled with the displacement and fixed keels of big cats. Trimarans are a little easier, with a single central daggerboard to act as a pivot, and one or other of the floats will generally be clear of the water. On the downside, light displacement means that there isn’t much momentum to keep you going through the turn and plenty of windage to stop you.

On a trimaran the central daggerboard helps the boat to turn by providing a central pivot point that catamarans lack

Speed is your friend. Build speed up before the tack to give you as much momentum as possible. The helm needs to steer positively into and through the turn, and if necessary, keep the jib backed on the new windward side to help the bow through the wind. Don’t worry about scrubbing speed off, but you don’t want to get stuck in irons.

When it comes to gybing, speed is again key. The turning bit isn’t going to be an issue as you’ll be scooting along, but the faster you’re going, the less load there will be on the sails. The more you slow down, the more the true wind will pile up.

Trimaran sailing skills

Tacks took a bit of practice. It felt plain wrong to jab the tiller across the boat, slamming a big break on in the water but I ended up putting us through the tacks far too slowly, losing a lot of speed. A more aggressive approach worked better. On the Astus, the traveller was between me and the tiller, so the tiller extension needed to be swung around the stern behind the mainsheet onto the new side.

Similarly, old habits of controlling a gybe needed to be modified. With the asymmetric set, we were planing at well over 10 knots, and the ideal is to stay on the plane. Heading dead downwind and centring the main lead to a more violent manoeuvre than flying into the gybe as fast as possible and, as the boom was never that far out thanks to the apparent wind angle, it didn’t need much extra controlling.

Coming up onto the wind after the gybe helped the asymmetric around the front of the jib and to fill on the new side. Stay too deep and it’ll get blanketed by the main. Once we had built up some apparent wind, we could bear away again.

You’ll be on a course deep downwind before you know it, hitting speeds in the double digits

Downwind in a trimaran

Upwind cruising may be fun in a multihull, but bearing away and going with the wind is what it’s all about. Easily-driven hulls, a generous sailplan and light weight mean you can be up and planing, leaving displacement boats wallowing in your wake.

The big difference comes from apparent wind. If you’re in a boat that can do 15 knots downwind in 20 knots of true wind, the resulting wind angles can really mess with your head.

To get going then, says Brian Thompson, ‘Use those leech tell-tales again when sailing downwind and reaching to set the correct twist through the mainsheet, and use the traveller to set the correct angle of the whole sail to the wind.’

As the wind and your speed builds, bear away and trim the main accordingly.

In theory, you shouldn’t need to ease the traveller at all, but you may need to if you want to sail deep downwind. As the gust fades, you’ll find the boat slows down, so you can come back up towards the wind a little to pick up some more breeze, and then bear away as you accelerate again.

Bear away as the boat accelerates. Your course will be something of a slalom as you look to keep a consistent wind angle

This results in something of a ‘slalom’ course, and will also be accentuated if you’re sailing down waves, but that’s all quite normal for apparent wind sailing. Ultimately, you’re looking for a consistent apparent wind angle, even if the resulting wake isn’t straight.

It’s worth remembering that apparent wind reduces the felt effect of the wind, so you need a sailplan to suit the true, not apparent wind speed.

I found that the boat was more sensitive to having a balanced sailplan and trim downwind than upwind, largely because you’ve got almost double the canvas up, with the bowsprit as an extra lever. When weather helm built, I needed to ease the mainsheet to increase twist to depower so that I could bear away. I must admit, getting the boat balanced, sailing fast and light on the helm at 15 knots was something I came away feeling I needed more practice at.

Reviewing the images, I suspect the asymmetric was sheeted in too hard, with too much twist in the main.

Getting a float fully submerged is when it’s time to back off

On the water

Unfurling the gennaker worked best on a beam reach, giving plenty of airflow over the sail to help it fully unfurl. This was also roughly the fastest point of sail, ideal for getting up some speed for apparent wind sailing. We mostly had the sails set for a close reach, even when we were beyond 120º off the true wind on a broad reach.

It was possible to soak deeper downwind, but lose the apparent wind benefit downwind and our speed dropped off dramatically, prompting us to point a bit higher to find some more speed.

As the boat powered up, it paid to hold a slightly higher angle than I would have done in a monohull for the boat to properly take off and get up into double digit speeds – topping out at 15 knots. Lymington to Cowes would have taken us just half an hour at that speed. It’s easy to give yourself a heck of a beat back!

We were sailing on a pretty flat day, so didn’t have to contend with any waves to speak of. On the recent RTI this is what caused the capsizes of at least two multis, a sobering reminder that you need to sail much more conservatively in lumpier conditions.

The bows want to point downwind, so a stern-first approach works with rather than against the boat

Coming alongside

A 650kg boat with no draught and plenty of windage feels dreadfully skittish when manoeuvring in confined spaces. Straight hulls with no forgiving curves and fragile-looking sharp bows make berthing tricky. You’ve got a couple of advantages on your side, however. In the Astus, the floats are at pontoon height making stepping off easy.

Whether you have an engine in each hull of a cat, or one in the central hull of a tri, there’s also a lot more leverage to play with to turn the boat and drive her on or off the pontoon. A steerable outboard gives you even more options.

If the boat has a lifting keel or daggerboards, put them down if there’s enough depth to give you a pivot and to resist drifting. Think about getting corners onto the pontoon, rather than putting the boat alongside. On tris, you won’t be able to get to the bow to fend off as it’s too narrow. You can rig a fender up forwards on a line, and two fenders are enough on the flat sides.

Steering with the outboard towards the pontoon will drive the stern in more; steer away to drive the bow in more

Offshore wind

Coming onto the pontoon with wind blowing off, it worked well coming in stern first. If there’s a tide running, you’ll want to be heading into the tide, so find a spot down wind and down tide to start your approach so you come in at an angle.

On our first attempt we had a bit of tide under us to start with so we came in at a much steeper angle, almost 90º, although this worked out OK in the end.

The crew could then step ashore, taking a line from the stern quarter round a cleat.

Drive forwards against the line and the bow will obediently drive up towards the pontoon, bringing you flat alongside. Getting off was simple, releasing the bowline, and allowing the bow to swing out the before slipping the stern line.

Coming in astern and stopping upwind of the berth meant the bows blew towards the pontoon far to quickly

Onshore wind

Getting onto and off a pontoon with onshore wind proved rather trickier. On our first attempt we came in stern first. The issue was that once we were just upwind of our desired berth and stopped, we lost steerage and the bow immediately blew off with alarming speed towards the pontoon.

Going ahead would only increase the force of the impact, while going astern only increased the bow’s sideways drift. I managed to back out without smashing the bow, but only just, and ended up awkwardly stern to the wind with the bows pointing at the pontoon.

On our second attempt we came in bows first but having aimed at the berth, I had to motor the stern to leeward to stop the bow hitting, making for a rather forceful coming alongside.

On take three, I came in forwards and began ferry gliding towards the berth early, keeping the bows to windward of the stern. Being able to steer with the outboard meant I could go ahead to keep the bow up, and go astern with the engine pulling the stern down toward the pontoon. In this way, it was possible to come in pretty well controlled and parallel to the berth.

To get out, motoring astern against a bow line pulled the entire boat clear before slipping the line

Leaving was a different proposition all together, as I didn’t want to drag the bow along the pontoon, or to drive hard onto it to spring off. Instead, we rigged a slip-line from the forward cross beam. Going astern against this, and then turning the engine towards the wind, I could pull the stern, and the rest of the boat, out and away from the pontoon.

Keeping power on astern, once we’d reached a decent angle, we slipped the line and went astern, finding steerage way almost at once, with the bow following obediently in our wake with more control than I had anticipated.

Whether the wind is blowing onto, or off the pontoon, you want the engine to be driving or pulling the boat off the pontoon with a line on the corner you are going away from. That way you avoid point-loading fine ends where it’s hard to fender.

You’ll want a bridle to reduce swinging, but keep the pick up lines on the bow as backup

Anchoring and mooring a trimaran

While mooring a catamaran is complicated by the lack of a central bow, things should be simpler on a trimaran, and they are, mostly. Picking up a mooring buoy from the main hull bow with a low freeboard and dropping the pick-up line onto a cleat is easier even than a monohull.

The bow may be narrow, but for any lines that pass through a ring on the buoy, you still need to take it back to the same cleat to avoid chafe. That should be it, but windage from the two extra bows and the lack of keel mean the boat can dance merrily around the mooring buoy in a breeze.

Rig the bridle so the buoy sits to one side to stabilise the boat

In practice, we found that a trimaran benefits from a mooring bridle in the same way that a catamaran does. It can’t be rigged from the floats’ bows, as there are no mooring cleats, so a line passed around the outboard ends of the forward beams gave a pretty good angle, again with long lines passed through the mooring and back to the same side. The main pick-up lines stay as a safety backup.

The other trick is to rig the bridle asymmetrically so that the buoy sits to one side or the other, just enough to not be dead head to wind, making it much more stable in the wind.

On the plus side, the lack of draught or keel means that you’ll nearly always be lying head to wind, so the cockpit remains nice and sheltered whatever the tide’s doing.

We ran out of time on the day to try anchoring, but rigging a bridle, effectively a long snubber to a point on the anchor chain in a similar way wouldn’t be tricky.

If you needed not to swing, or to behave more like deeper boats nearby, hanging a bucket over the stern can help, or there’s always anchoring with a kedge, either out ahead in a V, or in line astern.

Enjoyed reading this?

A subscription to Yachting Monthly magazine costs around 40% less than the cover price .

Print and digital editions are available through Magazines Direct – where you can also find the latest deals .

YM is packed with information to help you get the most from your time on the water.

• Take your seamanship to the next level with tips, advice and skills from our experts
• Impartial in-depth reviews of the latest yachts and equipment
• Cruising guides to help you reach those dream destinations

Follow us on Facebook , Twitter and Instagram.

Visit our Popular Forums

• Monohull Sailboats
• Multihull Sailboats
• Powered Boats
• General Sailing
• Antares Yachts
• Fountaine Pajot
• Lagoon Catamarans

Cruising Business

• Boat Classifieds
• General Classifieds
• Crew Positions
• Commercial Posts
• Vendor Spotlight

Life Aboard a Boat

• Provisioning: Food & Drink
• Families, Kids, & Pets Afloat
• Recreation, Entertainment, & Fun
• Boat Ownership & Making a Living
• Liveaboard's Forum

Seamanship, Navigation & Boat Handling

• Seamanship & Boat Handling
• Training, Licensing, & Certification
• Health, Safety, & Related Gear
• Rules of the Road, Regulations, & Red Tape

Engineering & Systems

• Const. / Maint. / Refit
• Product / Service Reviews
• Electronics: Comms / AV
• Electrical: Batts / Gen / Solar
• Lithium Power Systems
• Engines & Propulsion
• Propellers & Drive Systems
• Plumbing / Fixtures
• Deck Hdw: Rigging / Sails
• Aux. Equipment & Dinghy
• Anchoring & Mooring

Photo Categories

• Member Galleries
• Life Onboard
• Sailing in the Wind
• Power Boats
• Cruising Destinations
• Maint. & Boat Building
• Marine Life
• Scuba Diving & Divers
• General Photos

Recent Photos

Listing Categories

• African Cats
• view more »
• Crew Wanted
• Crew Available
• Enhance Your Account
• Meet the Mods
• Meet the Advisors
• Signup for The Daily Cruiser Email

> > Please support our sponsors and let them know you heard about their products on Cruisers Forums. 09-04-2016, 14:26   Boat: Custom Marples 40 FC sailor wants to hear from you..... How have you been rewarded with the conversion to sailing? Any regrets with the switch? Any bias' been left behind? Has the switch impacted your pleasure of cruising? Any converts gone back to sailing? What have been your pros and cons? Thinking about taking the plunge......... Tx. 09-04-2016, 14:40   Boat: We have a problem... A serious addiction issue. (racer), and a (daysailer). They are all great for different jobs, and I like them all. The cat is the most fun to sail, but is also the smallest and is a one person very physical to sail. The is probably the ideal day sailer, fast, good in light air, can stack a lot of people on it, low loads, rewards trimming but doesn't demand it. The monohull is great for weekending (and would be good for longer if I had the time). But I can't really say I love sailing it that much. It has its draw, but is by far the least rewarding to sail. 09-04-2016, 14:48   Boat: Custom Marples 40 FC 09-04-2016, 14:58   Boat: Wildcat 35, Hobie 33 (racer), and a trimaran (daysailer). They are all great for different jobs, and I like them all. .... 09-04-2016, 15:10   Boat: Custom Marples 40 FC type for two. That with no land based responsibilities. At least for awhile. mono may be a bit shy for that. But we have done it in the past. Have also done the two boat thing. Not to keen on that scenario. Leaning toward a nice tri along the Marples lines. 09-04-2016, 15:19   Boat: Ohlson 29 Hundreds more where those came from . . I live on a 29' boat and those tri's were well over 29' (Juniper was 52') but made me claustrophobic - Charles Baudelaire Dutch ♀ Liveaboard, sharing an Ohlson 29 with a feline. 09-04-2016, 18:15   Boat: Wildcat 35, Hobie 33 type boat for two. That with no land based responsibilities. At least for awhile. mono may be a bit shy for that. But we have done it in the past. Have also done the two boat thing. Not to keen on that scenario. Leaning toward a nice tri along the Marples lines. 09-04-2016, 18:53   Boat: Custom Marples 40 FC 09-04-2016, 19:02   Boat: Wildcat 35, Hobie 33 (about 5.5' already), so went wider rather than longer and got 3.5' to boot. 5.5' became an achorage...opened up a lot more cruising possibilites in SW FL. Very comfy for guests and too. Another related thread: 09-04-2016, 19:13   Boat: Custom Marples 40 FC 09-04-2016, 19:24   . I couldn't afford to buy the type of boat I wanted, so decided to build. I also had a list of things I didn't like about our old boat, so bulding gave me the opportunity to address these. Benefits are: performance, (by a huge margin) space, comfort, draught, economy of operation, ease of (outboards vs , fibreglass v steel), ease of handling (it's a far more easily driven boat, so loads are far less, also manoeuvring is easier) Downsides: marina would be higher, but we stay away from far more than we did with the mono, so it actually works out cheaper..... You have to put up with reams of uninformed opinion on , and very occasionally in person. 09-04-2016, 19:32   Boat: Lindenberg 26 & Aloha 8.2 space because they spread out into the wings for large rectangular berths. If you can find one built in composites one of these old boats would be good cruisers. There were Horstman and Cross tris built in foam/glass. I have sailed a little on tris by , Horstman and a summer of on an F27 when it was new including a 360 mile . Obviously the Farrier was a lot better performer but even the 31 is tiny inside. The thing I don't care for with either Monos or tris is that you are living in the basement looking up at the glimmer of light coming though the tiny little window and with the monos of course that heeling thing and the largest berth is usually that stupid vee berth that's wide at the and narrow at the foot. Of course larger modern monos have a lot better living space and light if not the view from the settee. Just my opinions of course. Steve. 09-04-2016, 19:49   Boat: Privilege 39 Catamaran, Exit Only was no object I would have the following: 39 catamaran (which is what I own now) Norsea 27 for trailering to special locations that I don't want to have to sail to get there. Westsail 42 or for high latitude sailing. I like the motion of a heavy monohull at sea better than the snappy motion of a catamaran. My wife wants a catamaran, so for the time being, that's my sailing machine. 09-04-2016, 20:06   Boat: Custom Marples 40 FC on a gaff rigged schooner. Fast and what a great motion at sea. I have been looking over a new Constant Camber Marples design for a 40 foot "Fast Cruiser." It is definitely a "cruising" trimaran and so sports plenty of room. Not to the extent of a big Cat.........but still plenty. All the numbers seem to hit the sweet spot for a good ocean going tri. 09-04-2016, 20:30   Boat: Pescott,Whitehaven, 11.7m so you could be able to get a very nice Cat at the moment especially in . I built my last 12m Cat and with unlucky timing fell into a trap . I still think to build will tax your and likely produce something that your labours will create that is unable to return its value so look around ,lots out there. I spent all of 2015 searching and visiting many multis throughout the world in my now reduced budget ,I finally found a properly built Western Red Cedar ENCAPSULATED charmer which is a performance cruiser , plenty of space inside and out . Some production glass foam boats are now showing their age and have structual weaknesses too thus my eventual preferance towards a very tough but light build technique. Lance , , , , Thread Tools Rate This Thread : Posting Rules post new threads post replies post attachments edit your posts is are code is are are are Similar Threads Thread Thread Starter Forum Replies Last Post Gisle Multihull Sailboats 565 23-12-2018 00:52 niel12 Multihull Sailboats 9 02-10-2011 03:44 maxingout Multihull Sailboats 13 20-07-2008 07:57 dcstrng Multihull Sailboats 193 10-07-2008 18:41 bahamarich Multihull Sailboats 6 09-10-2007 19:42 - - - - - - - Privacy Guaranteed - your email is never shared with anyone, opt out any time. Catamaran vs. Trimaran: The Differences Explained As an Amazon Associate, we earn from qualifying purchases. We may also earn commissions if you purchase products from other retailers after clicking on a link from our site. Most boat lovers know the differences between a catamaran and a monohull. But when it comes to differentiating between a catamaran and a trimaran, things can get tricky because it’s not always clear how much difference the extra hull of a trimaran makes in performance, safety, comfort, and handling. If you’re trying to choose between the two, this is a post you’ll want to read before making a decision. Besides the number of hulls catamarans(two) and trimarans(three) differ in speed, safety, accommodation, helming, and anchoring. Generally, catamarans are more manageable in a marina and provide better accommodation and comfort. Trimarans, on the other hand, are faster and more fun to helm. In this post, we’ll cover these differences in greater detail to make it easier for you to choose between a catamaran and a trimaran. First, let’s quickly review each multihull type. Table of Contents The Lowdown on Catamarans Informally dubbed a “cat,” a catamaran is a type of multi-hulled sailing craft with two equal-sized parallel hulls. Cats are typically geometry-stabilized, leveraging their wide beams for stability. That’s unlike monohull boats, which use ballasted keels for stability. Catamarans also have a smaller displacement, lower hull volume, and a much shallower draught ( draft ) than similarly sized monohulls. The earliest forms of catamarans can be traced way back to the 17th century. They were primarily used for fishing by the Pavaras community in Tamil Nadu, who preferred them over other fishing vessels due to the extra balance and stability provided by the twin hulls. Later on, the British adopted the concept of twin-hulled boats and popularized it worldwide. Modern catamarans are much more sophisticated than their ancestors. They’ve evolved in terms of the usage versatility, construction, and design, giving rise to two primary configurations: Small-Waterplane-Area Twin Hull (SWATH) Wave-piercing catamarans The hulls in a catamaran with a SWATH configuration are typically submerged. That means they’re less affected by ocean waves , which is great for stability when sailing in rough waters. In the recent past, SWATH configurations have been used on research vessels and rescue ships.  Their wave-piercing counterparts, on the other hand, have low-buoyancy bows fitted on the twin hulls. The bows allow the hulls to puncture ocean waves instead of riding over them, making catamarans with such a design faster on rough waters than SWATH cats. In the recent past, wave-piercing cat designs have been used on passenger ferries, military vessels, and yachts. The Lowdown on Trimarans Also known as a double-outrigger, a trimaran is a type of multihull boat with one main hull flanked by two smaller “floats” (technically known as outrigger hulls) connected to the larger hull by lateral beams. Such a design makes trimarans incredibly stable, meaning they’re hard to capsize even in the roughest of waters.  The earliest forms of trimarans can be traced to the Austronesian people and are still the most common hull design you’ll find on traditional fishing boats in Maritime Southeast Asia. The majority of today’s double outriggers are yachts meant for racing and recreation, but some warships and ferries have this design. The Differences Between Catamarans and Trimarans  The most apparent physical distinction between a catamaran and a trimaran is that it has three hulls instead of two.  But other than that, are there other differences between the two vessel types you need to know? Do those differences make one type better than the other? To find out, let’s compare the two types of multihulls based on the following merits: Comfort and Accommodation A Cat’s geometry is ideal for comfort and accommodation. The two load-bearing hulls provide additional habitable space, and you can always create a sizable nacelle between them. Connected to this central living space is a large cockpit, and there are cabins on either end of the hulls. This arrangement is perfect when you’re looking to relax a bit as the party rages on in the saloon because it gives you a bit of privacy.  And with flybridges virtually standard on modern catamarans, you have extra space for entertainment and lounging. The deck area is safe for kids, and the fact that catamarans don’t heel much means that you can do things like cooking at ease. Also worth mentioning is that cats can carry a decent load, meaning you can stock up on food and gear when going away for an extended period. While trimarans do provide a decent degree of livability, they fall short of catamarans in two regards. First, they heel more than cats, making it difficult to do things like cooking on board. Second, they support much less load than catamarans. To put things into perspective, some 45 feet (14 meters). Cats can carry nearly three tons of payloads, whereas similarly sized trimarans can barely support half that load. Overall, catamarans provide better, more comfortable accommodation than trimarans. One of the main concerns when choosing any water vessel is how easy it’ll capsize in the event of a storm. If you’re looking to spend more than just a couple of hours on the water, you want to sail on something that won’t capsize/sink easily because sea conditions can sometimes fluctuate within a short period. When it comes to safety, three hulls are better than two. Having one main hull and two overhangs on each side makes a trimaran more stable because of two reasons. First, the side overhangs widen the beam of the vessel, which minimizes the chances of the boat flipping over when hit by a large breaking wave from the side. Second, trimarans are typically designed with the weight centered on the main hull, further enhancing stability.  Multihull stability is a complex topic and should be understood in detail if you want to stay safe at sea! Why do catamarans capsize? On the rare occasion that a trimaran flips over, it’ll stay afloat. That means if the worst happens, a capsized trimaran will turn into a potential life-saving raft that’s easier to spot from a helicopter. That’s because almost all trimarans designed in the last decade or so come with closed-cell foam distributed throughout the various parts of the boat to provide reserve buoyancy.  Thanks to this kind of construction, you could cut most trimarans into pieces, and each would still stay afloat. While catamarans are typically more stable than monohulls, they’re no match for a trimaran in this regard. Hypothetically speaking, it would be easier to tip over a catamaran than a trimaran if both boat types were subjected to equal magnitude storms. That, however, doesn’t mean that catamarans aren’t safe. They’re still harder to flip over than monohulls and will stay afloat when that happens because they come with the same closed-cell foam found in a trimaran. While on the subject of safety, it’s worth mentioning that trimarans require less vigilance as far as reefing is concerned . Since catamarans heel less, most of the extra wind force translates to more “push” on the rig, increasing speed. But because the pressure exerted on the sail nearly quadruples when the wind speed doubles, you need to be extremely careful when timing your reef to keep a cat sailing flat.  The same goes for reefing a trimaran, except that the slight heel gives you more room for error in terms of the timing. Most people who’ve ever steered both a trimaran and catamaran will agree that the former is more fun to sail. Most light trimarans, especially tiller-steered ones, have a terrific response to the helm. They have a slight heel that somewhat feels like a monohull, but the angle is a bit limited. A catamaran is stable, but it doesn’t heel. While heeling may be frowned upon by people who prioritize comfort and accommodation in a boat, it’s one of the most exciting parts of sailing. With three hulls to ensure stability, trimarans combine the heel of a monohull with a catamaran’s stability to deliver the best sailing elements of monohulls and multihulls in a single package.   Considering that trimarans are more stable, you may be better off with one if you’re looking to have some fun as you perfect your helming skills. Speed is another area where trimarans outperform their twin-hulled counterparts. Typically lighter than catamarans, trimarans need less sail distance to hit double-digit speed averages. A trimaran can maintain a formidable course up-wind when fitted with centerboards/daggerboards (as is often the case for modern models). While a catamaran is still faster than a monohull of identical size, it falls short of the trimaran in terms of sheer speed. Understand that this doesn’t make catamarans slow boats; it’s just that tris are typically designed with more emphasis on performance. Why are Trimarans Faster Than Catamarans? Trimarans are easier to anchor than catamarans because they allow you to keep the ground tackle in and deploy it from the main hull.  However, catamarans are more maneuverable and manageable in a marina. They also handle docking lines more conveniently. Catamarans vs. Trimaran: The Verdict In summary, here’s what the differences between a cat and tri mean for anyone trying to choose between the two: A catamaran is a better choice if you’re looking to accommodate many people on board for something like a party because it’s more spacious and comfortable than a trimaran. On the other hand, a trimaran is an ideal choice for speed junkies and individuals looking to push their sailing skills to the next level on every stable platform. Hopefully, that has cleared the air and made it easier for you to pick a more suitable option for your sailing needs. ResearchGate: A comparison of the motions of trimarans, catamarans and monohulls | Request PDF Why are trimarans faster than catamarans? Owner of CatamaranFreedom.com. A minimalist that has lived in a caravan in Sweden, 35ft Monohull in the Bahamas, and right now in his self-built Van. He just started the next adventure, to circumnavigate the world on a Catamaran! Leave a Reply Cancel reply Your email address will not be published. Required fields are marked * Save my name and email in this browser for the next time I comment. Recent Posts Must-Have Boat Gear for Catamaran Sailors! Sailing is probably the most gear-intensive activity I've ever done; there are so many decisions to be made about what gear to buy now, for tomorrow, and what to definitely never buy. The gear on... 6 Best Trailerable Trimarans For Bluewater and Coastal Sailing Having a boat costs a lot of money, even when you are not using it, marina fees, etc. And once it is in the water most sailors never go very far from their "home marina" and sailing will be somewhat... The magazine Current issue All the issues My magazines Technical specifications Multihull of the Year Classified Ads Destinations Online store All the magazines Subscriptions Accessories Bluegame is a new brand from luxury multiyacht builder, the Sanlorenzo group.  Create a notification for Multipower We will keep you posted on new articles on this subject. Published 18/09/2024 By Kim Wellington Published: sept. / oct. 2024 Choose the option that suits you best! Issue #: 197 Published: September / October 2024 Price per issue - digital : 6.50€ Digital magazine Price per issue - print : 9.50€ Print magazine Price with subscription : from 2.91€ Subscribe The BGM75 is designed to be consistent with the rest of the group’s offer: the beam is reduced to the point of approaching a monohull size, and above all, only the forward view reveals the two hulls. From the side, and especially from the stern, the Bluegame appears to have all the design codes of a monohull yacht. The idea is therefore to gain in stability and, above all, to save fuel: the Design Office claims a 40% reduction in fuel consumption compared to a 90-foot monohull yacht - which, on the basis of 300 hours’ running time, translates into savings in the order of 17,500 US gallons (66,000 liters) of diesel, and that equates to 175 tons of CO2 emissions. The one-piece superstructure that widens as it goes forward - enough to accommodate a magnificent owner’s suite. Builder: Bluegame Architect: Briand Yacht Design Design: Lissoni & Partners - Zuccon International Project Length: 74’4” (22.7 m) Beam: 26’7” (8.15 m) Draft: 4’3” (1.3 m) Displacement: 105,800 lbs (48 t) Engines: 2 x 550 / 625 HP Max. speed: 20 knots Cruising speed: 17 knots Passengers: 16 www.bluegame.it   Tags :  Bluegame ,  BGM75 ,  Most-read articles in the same category Tricat 8.50 Lagoon Neo program Dragonfly Days 2024 Bourgogne Catamaran Rapido Trimarans What readers think. Post a comment No comments to show. Useful links MW #197 - Oct / Nov 2024 T-2000 Voyager 70 Sunreef Power Subscribe now The latest news from €3 / month Video of the month Our latest YouTube hit! The Multihull of the Year The 2024 results Classified ads TRICAT 30 PERFORMANCE TRIMARAN FARRIER F9AX Privilege 515 (2010 - refit 2021) v. 3 cabins Power catamaran Fountaine Pajot Greenland 34 - fully self-sufficient Vous avez ajouté " " à vos favoris., vous avez supprimé " " de vos favoris., in order to add this article to your favorites, please sign in.. Free Shipping in the US on Orders $75+ Item added to your cart The complete list of trimarans. There is no single trimaran that is best for everyone. Where some prefer luxury cruisers for long trips with family and friends, others might opt for a high performance racing tri for thrilling rides at breakneck speeds. With the recent spike in trimaran popularity, these days there is a perfect tri for every sailor. So to help prospective trimaran owners decide which boat is just right for them, we here at WindRider have put together a comprehensive list of the best trimarans on the market today! Read through for simple at-a-glance trimaran comparisons of boats both big and small, exhilarating and relaxing, and for all price points. Jump to a specific sailing trimaran: Neel Weta Corsair WindRider Dragonfly Catri Astus Hobie Sea Pearl Farrier Sea Cart Multi 23 Triak SeaRail Warren Lightcraft Diam Radikal Challenger Known for their award-winning luxury trimarans,   NEEL   is based in La Rochelle, the capital city of sailing in France. NEEL trimarans are built for fast cruising with an average cruising speed of about 10 knots, and are even configured to facilitate that sustained speed under motor propulsion. The NEEL 45 was notably named Cruising World’s Most Innovative Vessel in 2013, and by all accounts is an easy-to-sail, high performance boat that is just plain fun. At a glance: Models: NEEL 45, 65 Length: 45’ – 65’ Cost:   $$$$$ Use: Luxury cruiser A fan favorite,   Weta trimarans   are fast, stable, and remarkably easy to rig. This single-sailor tri has a capacity of up to three, and the ease with which it can be transported and stored makes this a great, versatile boat for beginners. The Weta was named Sailing World’s 2010 Boat of the Year, and one ride is enough to know why: simply put, the Weta is an absolute ton of fun to sail regardless of skill level. Models: Weta Length: 14’5” Cost:   $$ $$$ The high-end   Corsair trimaran   definitely holds its own in the categories of versatility, performance, and convenience. Boasting a rigging time of 30 minutes from trailer to sailor ,   the Corsair 42 – whose convenient folding amas makes trailering possible – is a simple option even for single sailors, though cabin space is suitable for two adults. These boats are wicked fast, capable of reaching speeds of 20+ knots, and were made for skilled sailors seeking solid construction and high performance vessels, not for beginners. Models: Pulse 600, Sprint 750 MKII, Dash 750 MKII, Corsair 28, Cruze 970, Corsair 37, Corsair 42 Length: 19’8” – 37’ Cost:   $$$$ $ Use: Sports cruisers Built for the sailor who wants to maximize the joys of sailing while minimizing any hassle, WindRider trimarans are notoriously fast, very safe, and a blast to sail from start to finish. With several models that can hold between 1 and 6 riders, including adaptive designs to allow participation from sailors of all levels of mobility, there’s something to suit every sailor’s needs. The WindRider 17, an exhilarating ride perfect for families or camper sailors, has been known to reach speeds of up to 20mph. This easy day sailor goes from trailer to sailing in under 30 minutes and is sure to fit in perfectly with whatever adventures you have planned. Models: WR 16, 17, Tango, Rave V Length: 10’11” – 18’3” Cost:   $ $$$$ Use: Day sailor The Danish-built   Dragonfly   trimarans come in a variety of models ranging from 25’ – 35’, all known for their spry performance, comfortable ride, and ease of use. Every model comes equipped with the unique “SwingWing” feature, a motorized system that can unfold the amas even while the boat is already underway – making it accessible to marinas and slips, and even makes trailering possible. Perfect for those who don’t want to sacrifice their comfort for high performance, the Dragonfly can breeze along at 13 knots while remaining one of the quietest compact cruisers out there. Models: Dragonfly 25, 28, 32, 35, 1200 Length: 25’ – 39’ Designed for both safe cruising as well as for high speed racing,   Catri trimarans   will make your day. Especially noteworthy is the Catri 25, a stable yet wildly fast foiling trimaran with accommodations for up to 6 people. With profiles optimized for speeds of 25+ knots when foiling, this is no beginner’s sailboat. The special attention paid to stability in the foil design allows the Catri to be a single sailor vessel, even at foiling speed, with no special physical abilities. Whether you’re taking a small crew for longer rides at shuddering speeds or bringing the whole family along for a shorter, but still thrilling sail, the Catri is truly one of a kind. Models: Catri 25 Length: 25’ Use: Cruiser/racer A popular brand of trimaran in Europe,   Astus   has recently made its way to the US market to the delight of sailors on this side of the pond. Designed to offer maximum pleasure with minimum hassle, all models of Astus trimarans are fast to set up, quick on the water, inherently stable, and always a joy to sail. Their outriggers are mounted on telescopic tubes for easy stowage and towing, and can even be extended and retracted on the water for access to narrow passageways and monohull slips in marinas. With models in all sizes and price points, Astus trimarans are a great option for any sailor. Models: Astus 16.5, 18.2, 20.2, 22, 24 Cabin: Some models Length: 16’ – 24’ Use: Sport cruisers HOBIE ADVENTURE ISLAND Great for beginners and adventurers alike, the   Hobie Mirage Adventure Island   series is nothing if not just plain fun. With the option to use as a kayak or as a very basic trimaran, the Hobie is transportable, versatile, unintimidating, lightweight, and wonderfully affordable. The pedal system known as “Mirage Drive” allows a person to pedal the kayak using their legs for an extra kick of movement in slow winds. Amas tuck close to the main hull for docking or car-topping, adding serious ease and convenience to the exhilarating experience of the Hobie. Models: Hobie Mirage Adventure Island, Mirage Tandem Island Length: 16’7” – 18’6” Use: Convertible kayak/trimarans Best known for its use in camp cruising excursions, the   Sea Pearl   offers a roomy main hull and particular ability to sail in very shallow waters, making beaching and launching a breeze. The lightweight Sea Pearl trimaran is easy to tow, and the larger-than-expected cabin opens this vessel up for overnight adventures with plenty of storage space. The simple design makes the Sea Pearl notoriously low maintenance, and the ease it takes to rig and sail it add to the overall delight of owning this boat. Models: Sea Pearl Length: 21’ Use: Camper cruiser Quick, lightweight, roomy, and trailerable,   Farrier trimarans   are made for versatility to fit every sailor’s needs. Different Farrier models are available in plan or kit boat form for those who appreciate building their boat themselves, but of course, also as the full production sail-away boat for the rest of us. Single-handed rigging and launching takes under 10 minutes from start to finish, minimizing hassle and getting you on the water fast. All non-racing Farrier designs use a minimum wind capsize speed of 30 knots or more to ensure safety for all those aboard. Add the roomy cabin and high speed capabilities to the equation and you’ve got a boat that is great fun for everyone. Models:   F-22, 24, 25, 82, 27, 28, 31, 9A, 9AX, 9R, 32, 33, 33R, 33ST, 36, 39, 41, 44R Length: 23’ – 39’4” Cost:   $$$ $$ Use: Sport cruisers/racers One of the biggest names in the game,   SeaCart   is internationally noted for its high performance trimarans that far exceed expectations for a production boat of its size. The SeaCart trimaran performs as brilliantly off the water as it does on with its super-light and efficient harbor folding system, making light work of trailering. Notoriously easy to manage and maintain, the SeaCart 26 One Design is the ultimate day racing trimaran, designed for both course and inshore/coastal distance racing. Absolutely worth the international buzz it has garnered, the SeaCart is a thrill from beginning to end. Models:   SeaCart 26 Length: 26’ A high performance racer class, the   Multi 23   is a lightweight, powerful trimaran known for its wicked speed of up to 25 knots. Multi trimarans of both available configurations were designed to give beach cat thrills and speed without any of the stability or seaworthy concerns. Open ocean sailing is no issue for the Multi’s big bows, which do their job to keep her stable. Built for sailors with a need for speed, the Multi makes a perfect weekend boat for racers, especially those with a taste for boat camping. Models:   Multi 23 Length: 23’ Another dual outrigger sailing kayak/canoe design,   the Triak trimaran   was designed to be effortless and fun, especially for beginners. Paddle the kayak with sails furled, use the foot pedals for an extra kick of momentum, or sail with just the mainsail – the only boat in its class to feature an asymmetrical spinnaker – for exhilarating speeds and a blast on the water. Car-top the Triak anywhere for a quick sail or plan for a week long expedition, but always count on having a great time on this easy little boat. Models:   Triak Length: 18’ Use: Convertible kayak/trimaran SeaRail trimarans   are known for being affordable, light weight, trailerable trimarans that offer the perfect combination of exciting and relaxing experiences to a wide range of sailors. Whether it’s day sailing with your family, resort or camper sailing, SeaRail trimarans are ideal leisure vessels. Leave the hassle to the other boats – the SeaRail takes you from trailer to sailor in 15 minutes. But don’t let its reputation as a leisure tri fool you: if speed is what you want, rest assured that the SeaRail can deliver that as well. Models:   SeaRail 19 WARREN LIGHTCRAFT Warren Lightcraft trimarans , another example of a convertible kayak-to-sailboat option, are known for their aesthetically pleasing designs that are also, as the name implies, very light for simple transportation and ease of use. Convert the kayak into a fast, high performance sailboat in just minutes, fly around on the waves all day long, then simply car-top the 68lb Warren for a maximum enjoyment, low-hassle day on the water. Perfect for sailors and paddlers of all skill levels, the Warren Lightcraft is the best of both worlds and an absolute joy to sail. Models:   Warren Lightcraft Length: 15’6” Built strictly with racing in mind,   the Diam 24   is a light, powerful one-design class trimaran and a notoriously exceptional performer. Boasting blistering speeds of up to 30 knots, Diam trimarans are not intended for beginners. For racers who crave the very best in terms of intense speeds, smooth handling and impeccable performance, the Diam is the red-hot one-design racing tri for you. Models:   Diam 24 Length: 24’ For the sailor who prefers the finer things in life, the   Radikal 26   delivers. Perfect for bringing the whole family out for a day on the water, this high performance, trailerable sailing trimaran strikes the most luxurious balance between quicksilver speeds and a smooth, comfortable ride. The Radikal 26 trimaran is as convenient to transport and set up as it is pleasant to sail, with a folding system that minimizes rigging hassle and also makes this a trailerable tri. Built for a fast and comfortable sail rather than a hold-onto-your-seats thrill, one-the-water safety and overall pleasure makes the Radikal 26 what it is. Models:   Radikal 26 Use: Sport cruiser A solidly-built, single-handed trimaran, the Challenger also doubles as an adaptive design – meaning it is made to accommodate sailors of all levels of physical mobility. Best suited to lakes, the Challenger is a very safe, seaworthy boat for sailors of all ages and experience levels. Add to this the ease of owning, transporting and maintaining the Challenger trimaran and what you get is a simple, fun sailboat perfect both for beginners and those seeking a cheap thrill alike. Models:   Challenger At a glance comparison: Astus 16.5, 18.2, 20.2, 22, 24 16’ – 24’ Sport cruiser Some models Catri 25 25’ Cruiser/racer Y Challenger - Day sailor N Pulse 600, Sprint 750 MKII, Dash 750 MKII, Cruze 970, Corsair 28, 37, 42 19’8” – 37’ Sport cruisers Y Diam 24 24’ Racer N Dragonfly 25, 28, 32, 35, 1200 25’ – 39’ Luxury cruiser Y F-22, 24, 25, 82, 27, 28, 31, 9A, 9AX, 9R, 32, 33, 33R, 33ST, 36, 39, 41, 44R 23’ – 39’ 4” Sport cruisers/racers Y Mirage Island, Mirage Tandem Island 16’7” – 18’6” Convertible kayak/trimarans N Multi 23 22’ Racer Y NEEL 45, 65 44’ – 65’ Luxury cruiser Y Radikal 26 26’ Sport cruiser Y Sea Pearl 21’ Camper cruiser Y SeaCart 26 26’ Racer Y SeaRail 19 18’ Day sailor N Triak 18’ Convertible kayak/trimaran N Warren Lightcraft 15’6” Convertible kayak/trimaran N Weta 14’5” Racer N WR 16, 17, Tango, Rave V 10’11” – 18’3” Day sailor N Did we miss one? Let us know. Tell us what you sail and what you like about each boat in the comments below. Choosing a selection results in a full page refresh. Opens in a new window. Log in or Sign up You are using an out of date browser. It may not display this or other websites correctly. You should upgrade or use an alternative browser . converting convential mono sail to tri-haul/outrig Discussion in ' Multihulls ' started by dem45133 , Aug 4, 2006 . dem45133 Junior Member I started into this site when I got turned back onto water and spotted a sportfisherman in my low (read as almost non-existant, but there is a small means) boating budget. But when I calculated the $1.60 per MINUTE to feed the thing under way, I've re-thought that approach. I'm handy... real handy.. and can design build most anything if I research it enough. Thinking now on sail, as I have enjoyed that the few times (once on a 5 day criuse on the Manatou out of Traverse City MI.. NEAT Boat!). But here's the 1st catch... To get big enough on sail to do extended multi week criuses (you know ...actually go somewhere...) require at least 28ft or more if I can afford it. But about 28 feet or so is the limit for self hauling behind a heavy 3/4 ton even with a wide trailer permit. The weight is now getting into the equation. Mostly due to ballast. The second catch is an affliction my wife has called Maneir's (sp?) Disease ... an inner ear problem which cause balance issues when the eyes can't lock to things and maintain equalibrium. (and no... you will not call my wife dizzi... and she's not blond.... and she'd likely kick your you-know-what in a heartbeat if you did... ). It really is a disease... and will only get worse with time. She does real well with it most days, but extreme heeling over will be an issue. No sense in it at all if she will not be comfortable. She been my partner through thick and thin for many years now... not interested in it if she's not there. Both of these got me thinking about multi-hulls. A breif search did not locate anything affordable... This got me thinking about modifying an older 30 or 32 narrow to be more or less a shallow draft partial V bottom... and adding 22 or 24 foot (or ??) outriggers... and intead of going with a single large (read as tall) mast, go with the shorter twin masted ketch rig. This oughta, at least in thought, allow for a relative stable shallow drafted and roomy semi-live aboard that one does not need to be a millionare to afford. I want to sail portions of the great lakes, so what ever I do needs to be able to handle 6 ft seas on occation (yea I know thats only if it caught me or the weatherman offguard and am now headed for cover somewhere... but no doubt it will happen on those lakes!). Do outrigged vessels hand rough sea very well? Anybody seen anything along these lines anywhere or did it yourselves? Thanks again. Dave   catsketcher Senior Member they are out there Hello Dave, Before you go building yourself a converted boat I would look carefully at the Farrier trimarans available. The older Trailertri 720's are good boats and affordable. Dragonflys are also good boats and will be less costly in the end because you will be able to sell it for a good price later. It took about 20 years for this to sink in - you want to have a boat you can sell if it costs much money. Converting monos is rarely successful and the engineering problems are severe. One reason there are mainly Farrier tris around (in the trailering department) is that the engineering of his boats is one of the very few ways to have demountabilty and seaworthiness. Many thousands of hours have been spent on this problem so my advice would be to do lots of talking to lots of people who know trailerable multihulls and learn from what they know. My back ground on this has been developing a folding catamaran. This has taken over my life for 5 years and I am an experienced sailor/builder and trained in physics and I am not there yet. You gotta be a little crazy! Cheers Phil Thompson www.foldingcats.com   tspeer Senior Member dem45133 said: ...But about 28 feet or so is the limit for self hauling behind a heavy 3/4 ton even with a wide trailer permit. The weight is now getting into the equation. Mostly due to ballast. Click to expand... sigurd Pompuous Pangolin plug Maybe you would like to look at Rob Denney's proas; www.harryproa.com . They are said to be cheap for the accomodation since they don't use a lot of material. But there are probably none second hand. Some are trailable but I don't remember what sort of mechanism they had. They are opposite from trad. proas in that most weight and the accomodation is to windward so they should heel very little. Rob visits these fora from time to time at least. Good luck, hope you find a nice boat.   nero Senior Member Some 8 meter cats are demountable and can be towed at one time. There is one in Shuttleworth's collection that has been sailed across the atlantic. This should survive the great lakes (all tho the waves are probably steeper) http://www.john-shuttleworth.com/Images/8MCheetah-thumbs.html Rob's proas are interesting also. He is into building things in the least expensive manner. His plans are affordable also. As an idea, I posted a .dxf file of a harry proa. It has the lightbulb hulls in order to get some more living space inside. With Rob's help you could maybe work that into something doable. All the above is if you plan on building. There is also k-design. The have some cats that look quick to build. One of them uses a novel sideways fin. No daggerboards or keels.   Thanks all. I appreciate it, and I will be taking a look at your suggestions. AS yet, I have not sailed on a modern sail. The sailing I've done was on a small 16ft cat, or on the Manitou... neither of which really count toward experience... but are credited with creating the big tease. We got 12 knots out of the Manatou...which is hull speed... and it was really neat!. And before you all say it... I will not be sailing any open water great lakes until I've I gain some time and experience in protected waters. (we won't talk about when I took my little 1962 14 ft Sea Mac w/35 Evinrude [a plywood runabout built in Toms River NJ] out to the Otter Island of the Apostle Islands of Lake Superior loaded to the gunnels with camping equipment and a 16ft kayak.... all went well, but the 4 ft chop coming back was interesting...although she handled it well at about 1/3 throttle... or about taking her out the Barnigate Bay inlet... ocean swells are real strange in a little boat BTW... but I was 20 then not 53). I still have that little boat although she hasn't been wet in 15 years. I keep threatening to restore her and use it antique boat parades. Still ran fine last time out. (Although the State of Ohio wants Titles which never existed... I bought her for $100 when I was 17... I traded a motorcycle for the 1959 Big Twin Evinrude at 19... and even though I can show a PA and Wisconsin registrations they won't take it!!!!!!! AGGGH! So it’s not been use since moving here. Just sits in the shed gathering dust and probably some more dry rot. I know I talk too much. Keep feeding...I need to learn a lot... the designer in me thinks too much and as Phil stated above... you’ve got to be a little crazy... Yea... It fits... just ask my wife. Thanks, Dave   As quoted from Tom Speer above "A trimaran is an integrated system - it's not a "monohull with training wheels". If you try to convert a monohull into a multiull, you get the worst of both worlds." Tom, con you expound on the above statement? Since I am still in the infancy learning stage...please expand on what is the "worst of both worlds". My curiousity hurts. Thanks. Dave Hillsboro, Ohio   Hobie/J24 Trimaran Conversion thread http://boatdesign.net/forums/showthread.php?t=7206&highlight=j24 tri In this thread most of the reasons why not to do a conversion are mentioned.   dem45133 said: This got me thinking about modifying an older 30 or 32 narrow to be more or less a shallow draft partial V bottom... Click to expand... Advertisement: hansp77, I will, and her concerns are part of all decisions.   Converting an ole motor boat to a trimaran, AND sailboat converting moments of inertia into metric Converting a sailing cat into a power one Converting a beach cat rig for cruising No, create an account now. Yes, my password is: Forgot your password? 274 IMAGES Converting monohull into trimaran High-tech watercraft transforms from monohull, to catamaran, to Converting row boat to sailboat ~ DIY canoe pontoon High-tech watercraft transforms from monohull, to catamaran, to Bury Design Meluncurkan Yacht Monohull 57m Trimaran, Inception 24m Kormaran Watercraft : A Monohull, Catamaran, and Trimaran in One VIDEO Neel 45 Trimaran Neel 45 Trimaran Neel 45 Trimaran DF95 tri January 1 2024 Corsair Sprint 750 MK II trimaran motorboat faux tri ama powerboat.MOV COMMENTS converting a monohull into a trimaran monohull to trimaran Hi Tom, I was just searching for the same issue. My boat a Beneteau Oceanis 390 is quite comfortable but slow (max 8 knots). My idea was to convert it into a trimaran using pre-manufactured parts. Got to the f-boat site with their folding beams. I'm at the moment checking out that posibility! Converting a Monohull to a Trimaran .. and what to consider But remember that 1) sails on a multihull generally need to be cut a little flatter than for a monohull and 2) the stability of a trimaran will increase the load on both the mast and sails, so if coming from a beach cat, it's recommended to cut down its mast length to not exceed 1.35L of the original beach-cat length .... or if from the main ... Convert Mono Hull to Tri? The images shown below represent a working versions of a slender monohull conversion to very functional trimarans. If the base hull is selected carefully, you are capable and willing to make rather extensive mods to the original hull, and have more than a passing understanding of how to balance and properly engineer a boat of this type, it can ... Converting monohull into trimaran Converting monohull into trimaran. Discussion in 'Boat Design' started by sailor182, Jun 5, 2013. Joined: May 2013 Posts: 18 ... Why convert a mono hull? In my area all the harbors are at capacity with a ten/fifteen year waiting list so there are a lot of decent sailboat on trailers going for cheap. Interior space wouldn't be too shabby ether. Monohull vs Trimaran Inherently, a multihull is more stable due to its width. While sailing, a trimaran does heal a little, somewhere in between a monohull and a catamaran. While at anchor, our trimaran does rock a little, more so than a catamaran, but less than a monohull. Performance: Since a multihull is inherently stable in it's design due to its high 'form ... J-24 Sailboat Converted to a Trimaran Our small tri friend Stefano M. sent me links to the following YouTube videos. They feature a J-24 sailboat converted into full-blown trimaran. The sailor (s) responsible for this appear to have done a fine job. Converting a monohull into a trimaran has certainly been done before. But it's not for the faint of heart :-) Another Look at the Tricote Trimaran Another look at the Tricote trimaran, which was made from a monohull that has been converted to a trimaran +(44) 01590 619315 The online community for enthusiasts of trailerable ... Another example of a very beam-y main hull performing well…I contend that this boat and the J-24 conversion manage this because (besides being very light to start ... Why Choose a Trimaran over a Monohull? Corsair trimarans, and most others, have a max heel angle of 12-14 degrees depending on the model. That's "flat sailing" in monohull terms. And it means that rudders and daggerboards keep a reassuring grip and the speed therefore feels more effortless on the helm. That surefootedness transfers over to your crew - they'll detect the ... The best of both worlds? Introducing the world's first trimonoran Top stories. A radical new foiling hull design claims to combine the efficiency of a trimaran with the space of a monohull — Hugo Andreae takes a look at the world's first trimonoran motoryacht. Award-winning Turkish yacht designer Baran Akalin has combined forces with Dutch engineer G. Jelle Bilkert to create what they describe as the ... Why You Want a Trimaran: Pros and Cons of a Trimaran Consider the alternative to a trimaran: an equivalent monohull. For the monohull, we strip off the side amas and widen the center hull to maintain ship stability. But bad news. A wider hull requires a larger engine, and associated support machinery. In general, the machinery accounts for approximately 50% of the total build cost. How to sail a trimaran For their size, trimarans can punch well above their weightin speed, cruising potential, and fun. Monohull sailorTheo Stocker gets to grips with how to handl... Trimaran Conversion on the Cheap Trimaran Conversion on the Cheap. Discussion in 'Multihulls' started by Chuckles, May 4, 2015. Page 1 of 2 1 2 Next > Joined: May 2015 Posts: 4 ... In many ways a cat or tri is much better than a monohull since it will not heel nearly as much, adding to the worry of a newbie. So consider making a suitable center hull, with a comfortable (even ... Wow, that was fast! Why trimarans are SO much fun to sail Trimaran sail trim. One of the biggest differences between a cruising monohull and a multihull is how the mainsail is trimmed. Leech tension on a yacht is often largely controlled by the kicker and the backstay, while the mainsheet sheets the mainsail in and out, predominantly controlling the angle of the boom to the centreline, and there may be a short traveller. Monohull converts to multihull sailing.......... I like them both. Currently we own a monohull (cruiser), a catamaran (racer), and a trimaran (daysailer). They are all great for different jobs, and I like them all. The cat is the most fun to sail, but is also the smallest and is a one person very physical boat to sail. The trimaran is probably the ideal day sailer, fast, good in light air, can stack a lot of people on it, low loads, rewards ... DIY Canoe Plus Hobie Conversion to Trimaran http://www.smalltrimarans.com - Short video featuring sailor Greg Petroski having some fun on the water with the trimaran he made using an used canoe and old... Catamaran vs. Trimaran: The Differences Explained First, they heel more than cats, making it difficult to do things like cooking on board. Second, they support much less load than catamarans. To put things into perspective, some 45 feet (14 meters). Cats can carry nearly three tons of payloads, whereas similarly sized trimarans can barely support half that load. Converting an ole motor boat to a trimaran, AND sailboat A 30ft long boat about 2metres.6;6 wide would make a good river/lake craft. I haven't seen any fiberglass powerboat hulls with dimensions anywhere near 30' x 6'6". Two hulls joined together just doubles the drag, not going to sail well, especially with low tech sails. Trimaran, made from a Monohull The below creation was just featured in Norwegian sailing media. Apparently a german project named "Mia". The report says that the centerhull used to be a Dehler 41DS. Pics shot by Helge Iversøy at Ponta Delgada. I have seen lots of discussions about using a monohull as the basis for a trimaran. This is the first time I have actually seen such ... BGM75 The BGM75 is designed to be consistent with the rest of the group's offer: the beam is reduced to the point of approaching a monohull size, and above all, only the forward view reveals the two hulls. From the side, and especially from the stern, the Bluegame appears to have all the design codes of a monohull yacht. The Complete List of Trimarans Their outriggers are mounted on telescopic tubes for easy stowage and towing, and can even be extended and retracted on the water for access to narrow passageways and monohull slips in marinas. With models in all sizes and price points, Astus trimarans are a great option for any sailor. At a glance: Models: Astus 16.5, 18.2, 20.2, 22, 24 Electric Multihulls The electronically controlled ServoProp, as it's called, can produce 1kW at 6-8 knots of boatspeed. Tests on a 38ft monohull produced 3kW at 12 knots. Different mentality. Even with a decent solar array and a regenerating propeller, range still is going to be an issue for all but the lightest and fastest multihulls. converting convential mono sail to tri-haul/outrig A trimaran is an integrated system - it's not a "monohull with training wheels". If you try to convert a monohull into a multiull, you get the worst of both worlds. The unfortunate fact is that you can't build a boat for less than buying a used boat that does what you really want. catamaran gulet motorboat powerboat riverboat sailboat trimaran yacht