The new DC-3 Trimaran, designed by John Marples, has just been announced as the winner of WoodenBoat Magazine’s “Pro-Boat Design Challenge III.” It’s a 27-foot, trailerable, swing-wing wooden tri with offshore capabilities.
Some of its other features include:
— Central cockpit (for safety in heavy weather)
— Hulls built with the Constant Camber system (for faster construction using less wood)
— Ability to sleep at least 2 persons (in relative comfort)
— 2 separate (fore & aft) cabin areas (for reasons John discusses in the audio below)
There were 49 entrants from a half dozen countries that participated in this design challenge. And to get a fuller picture of the specific parameters that defined this year’s contest — the creation of a “Fast Expedition Sailboat” — I asked John if he’d participate in a short recorded call so I could ask him some questions.
So click on the audio bar below to listen, and John’s drawings can be viewed (in pdf) underneath the jpeg images below…
DC-3 Trimaran features fore and aft cabin
John Marples DC-3 Trimaran Model
Central cockpit and swing wing akas are part of the Marples DC-3 trimaran model
DC-3 trimaran requirements were for an Expedition sailboat
DC-3 Trimaran Sail Plan
DC-3 Trimaran Interior
Click here to download the DC-3 Trimaran sail plan drawings in pdf
Click here to download the DC-3 Trimaran interior drawings in pdf
Hi. I’m looking since a long time into ways to reduce the size of a small trimaran, a 22 ft (6.5) meters of my own design, very similar to this one with a central cockpit. Having owned a Farrier trailer tri 720 I can sware about the robustness of that system but also the heftiness and complexity: aligning 5 bolts per side into their respective threads was almost a miracle each time. I would be very suspicious of this swing wing system proposed as it looks very week in terms of engineering especially for a ri this size. Can the topic be discussed further? what about adding a rigid strut (removable) when the beam is open.
Could you also discuss this option versus a sliding tube? Has the system been proven and for how long? and boats what size ? Any suggestions to avoid structural failure also due to wood decay ? (farrier ply tris had the problem of freshwater remaining in beam slots and decaying the beam seat.
thanks in advance, Stefano
Hi Stefano,
This wooden swing-wing system was created for its simplicity, economy and strength. I’ve spoken to Jim Brown and John Marples about it several times over the past year and know that the engineering calculations indicate these beams can surely handle the stresses for this platform if they’re built according to John’s specifications. Seriously, other parts of the DC-3 would structurally fail (and we’re talking about this happening in the sorts of extreme conditions that would destroy any kind of boat) long before its beam connective system would come apart. What you’re seeing here is the model for a wooden swing wing system costing a homebuilder between $200-$300 to construct that is probably stronger than fabricated swing wing systems costing many thousands of dollars to produce.
Good to learn… what about one specific post on trailerable tris folding systems ?
Thanks for your prompt reply
Here are a couple of older posts that link to articles on folding systems that can be/have been used for small trimarans …
http://smalltrimaran.co.uk/?p=271
http://smalltrimaran.co.uk/?p=277
Yes, read the whole…shivered at the description of beams flexing under floats weight. A swing wing system in wood is not even cited in the article. Only aluminum alloy (ladder, closed triangle, Farrier, and stainless steel ( dragonfly) are discussed.
I think that on an “expedition boat” this subject should leave no doubts to the perspective builder about it’s proven capability to bear with a certain margin of safety the involved stresses, and this is what I would like to read about really.
The articles that I referred you to (above) were written before the wooden swing-wing system came out last year. Jim Brown (multihull pioneer with 50 years of real-world experience) conceived of it and John Marples (an engineer with decades of proven experience) performed the calculations and drew up the building plans for the wooden swing-wing folding system. To my knowledge, no 3rd party engineer has stepped forward and said that they doubt it will hold up under the stresses. Even though more information should be available after Woodenboat publishes the results, I have learned from John that the DC-3 beams are very heavy and are re-enforced by waterstays of synthetic (Dyneema). The waterstays will provide added support to the beams and reduce beam deflections to stabilize the rigging, which will be attached to the amas.
If I were you, I’d email a few other multihull designers and ask them whether or not this folding system will be able to handle the stresses placed upon it Why not contact multihull guru Dick Newick and see what he thinks about it? Contact Scott Watts (a boatbuilder with decades of experience at http://www.seaworthysolutions.net) who build the first swing-wing system for a Seaclipper 20 and see what he has to say about it. Ask him if he thinks it will work. Ask him if he thinks this system is at least as strong as a Farrier or Dragonfly folding system. Such questions cannot be left up to the imagination. There are mathematical calculations that determine such things. Engineers perform calculations to determine what the stresses will be and what the strength and size that the material used to handle such stresses will have to be in order to do the job. The performance success of Marples’ designs over the years is a testimony to the fact that he does these things very well.
While the wooden swingarm system may intuitively appear to be less than robust, it’s worth considering that far larger and heavier wooden masts have been successfully raised and lowered with tabernacle setups for eons…certainly many have failed, but more often than not it’s an issue of poor maintenance and/or sheer operator stupidity that makes them come down catastrophically.
The design itself is interesting; I’d love to see some views from a non-bird’s eye level just to get a better feel for how the unusual reversed cabin side angle is going to look in real life…that shape has something of a 1960’s plywood cabin cruiser-ish vibe to it that I don’t hate at all, but will no doubt grate on some people’s sensibilities. At the very least it should be a fun view from inside in a big seaway.
The audio clip gives a great insight into how *real* designers approach a project- while I may not agree with every conclusion or solution he proposes (beaching a boat this size in lieu of having a tender seems at best highly impractical in the kind of cruising situations it is touted as being capable of and it’s not like tris are lacking for deck space), the designer has obviously made a disciplined effort to consider all aspects of what this kind of craft needs and doesn’t need, and has left very little to chance.
Finally, as I read about the design I couldn’t help thinking that my Cross 24 had nearly the same accommodations- a (custom) double berth on the wing and a vee berth forward, head, a bigger galley area, and a huge storage locker aft of the very dry centrally located cockpit…of course it didn’t fold and had a pretty deep draft for a tri with its fin keel, but it’s still a pretty impressive accomplishment and properly outfitted and rigged I have no doubt that that boat could manage some serious offshore passages without too many white knuckle moments.
This isn’t in any way meant to disparage John Marples or his design, but more to point out that a) Norm Crosses design concepts are *still* hard to beat and b) there’s already quite a few trimaran designs out there in this size range that are capable of short and even extended offshore cruises, going back to the early Pivers, with trailering capability being fairly common in the newer designs.
Again, nobody should blame John for adding one more to the mix; but I think this speaks more to the notion that maybe the traditionalists at Woodenboat aren’t quite up to speed as far as what the world of trimarans needs more of*…
then again, in their defense it’s not like they were going to come up with an identically sized wooden monohull or catamaran with the same speed and accommodations, so maybe they had no choice but to pick the best tri design they received :)
*FWIW- in my opinion, there is a woeful lack of dinghy sized (10′-14′ or so) one design and development class trimarans out there intended for sail training, racing and general fun and especially needed is a very small, simple entry level boat of a standardized design that could be built quickly by DIYers and sailed by kids…basically a trimaran version of the Sabot or Optimist style boat that would be faster, safer and would contribute immensely to the ranks of future small trimaran fans.
Yes Ian … sure would love to see more quick-construction “dinghy tris” for homebuilders.
Response to the “lack of dinghy-sized tris” above: Isn’t there a wooden tri of about 10 feet length that fits this bill exactly? Do I recall correctly that Marples has built one? (Of course, a plastic one exists from Windrider Trimarans.)
Ian’s last paragraph on a small dingy sized trimaran is interesting. I have had the same thoughts. I am about three weeks away from having a dinghy sized tri finished. I wasn’t able to work on it in May, or it maybe would have been finished by Memorial Day. Construction started last December.
This is a new, unproven design. We’ll have to see how it sails. Sailing performance is a big unknown now.
The main hull is tall, 32 inches, and narrow: about 1 foot wide at the water line and two feet wide up at the gunwhales. This is a really tall main hull for a dinghy. But with the main hull being so narrow a la tri standards, the height is needed to have enough bouyancy for crew on such a narrow hull and to hopefully tame a tendency (if any) for pitchpoling. The ride should be drier than if the freeboard was more canoe-like. The footwell as a consequence can be self draining as the sole is well above the waterline.
The main hull is tortured ply, which provides a vee bottom and a bow with a fine entry. The amas are 20 inches high in the center with a vee cross-section with a bit of rocker. It’s hoped that this rocker will facilitate tacking while also assisting against leeway. The main hull has very little rocker hopefully to avoid hobby horsing and to preserve as much bouyancy as is reasonable in a short dinghy sized hull. If I built this a second time, I might use less rocker toward the bow of the outriggers and end up with a bit more bouyancy. We’ll have to see how this sails (or doesn’t sail) before making a final decision on this.
The main hull looks good, particularly from the front. It’s my favorite component. Tortured ply is a relatively easy way to get a good looking hull shape.
I’ve built tortured ply canoes before. They usually have a hard knuckle up by the bow where the folding seam starts. For some reason, the knuckle on the main hull is really subdued if it’s noticeable at all. The transition is very smooth, at least under workshop lights. I can’t figure out why unless the height of the bow of the main hull, which is nearly double the height of a tortured ply canoe bow, spreads the knuckle effect over a much wider area? It remains a mystery.
The cross beams are store-bought galvanized constructions that should have an abundance of compressive and tensile strength for a small dinghy. Ignoring their immense compressive and tensile strength, they are rated to deflect only a fraction of an inch if 3200 pounds is applied to the center of the ten foot beam supported only at the ends. Did I mention the beams were inexpensive? To get these beams boat ready, all they needed was paint. This means about 0 time is spent building beams.
Assuming it sails properly, the boat will carry a crew of two or an adult and two kids . . . in theory. The three hulls provide roughly 1400 pounds of flotation, with the main hull being a big chunk of this. My fingers are crossed.
This prototype was made to test out some design and construction ideas on a small scale. A “real” version would be scaled up to 16 to 20 feet, perhaps requiring more robust beams (perhaps using an assembly of the same store-bought constructs in a beefier assembly).
Each outrigger weighs about 45 pounds. I think I could save about 5 pounds in a next iteration as I used 1/2 ply for the 5 outrigger bulkheads with no cutouts. I used fir for the two deck beams on each outrigger. Cedar beams will work and will be lighter. The main hull with decks will be about 125 pounds. I could save maybe 20 pounds in a next iteration. Each cross beam weights just under 14 pounds, which is not so bad. Comparable Fiberglass beams are available via special order. Although lighter and corrosion resistant, these are not as strong and cost a lot more. Maybe fiberglass beams would be strong enough, but I haven’t investigated that. If the boat sails well in its current form, I might keep the scantlings as they are and not go lighter.
There’s an article that suggests that highly rockered outriggers have some drawbacks. But, that article expressed design concern on a much larger boat whose main hull also had considerable rocker. We’ll see what happens at dinghy scale with a low-rocker main hull.
If sailing balance is iffy, the design will allow the position of the outriggers to be shifted forward or aft to try to tune the balance if needed. About 180-200 total hours of construction time are involved, including more hours than I would have guessed for fairing and painting, assuming I have roughly 25 hours to go. About 30 hours were wasted having to fix mistakes and doing some things over. All three hulls were built in parallel, which contributed to efficiency considerably.
The height of the outriggers relative to the main hull can be varied by swapping out struts where the beams mount to the outriggers, if needed. This will have to be tuned with the water trials. I’ll bring 3 strut sizes with me on the launch day to see what works best.
Auxiliary power currently is an electric trolling motor mounted to the port side, rear beam. A 12 pound tractor battery in a box is mounted to the same beam on the starboard side. Wires run inside the beam are out of the way. The tractor battery won’t allow running the motor for an extended period, but I’m hoping it’s only needed to get away from the launch site and then come back in. Theoretically, there’s more than enough juice for these two minor motoring operations and a little bit more. I have the battery already. I have the motor already. Why spend any more $$$ for auxiliary power on an unproven design?
If the boat fails to perform and the reasons can be pinpointed, there will still be lessons to be learned that may benefit future builds. Maybe this design could be fixed as well depending upon what is pinpointed.
Wade- I’ve seen a couple of boats in this range, but aside from the windrider one they seem to be more of a one-off thing designed for the builder’s very specific needs, as opposed to a standardized one design/class type of thing. And as much as I get why some people like the sit down foot pedal steering approach so many DIYers and production small tris are going towards, in my humble opinion part of learning to sail is understanding how live ballast works, so in my perfect world a small sail trainer tri would require some moving around, hiking, etc. instead of being something you just sit in and drive.
David- sounds like you and I are on the same path…I’ve been playing around with ideas for this type of boat off and on for quite a while, and am now at the working model building stage…my design is very similar to what you describe- very fine entried and tall main hull of about 10′ in length built with a tortured ply/stitch and glue hybrid technique, with each ama developed from a single 4X8 sheet using a similar technique with a bit of origami tossed in…
Just like with the small prams mentioned above, I’ve sacrificed some aesthetics and optimum hull shaping for ease of building and especially for light weight, which is going to be key for anyone attempting this kind of boat and can make up for a lot of the kinds of speed-sucking bumps and weirdly shaped runs you mention that this kind of developed sheet hull is prone to have. As it stands I’ve managed to get the hull sheathing down to two 4×10 sheets for the main hull and one sheet each for the amas, and my plan is to use thin wall 6000 series aluminum for the crossbeams.
As soon as I have a presentable model I’ll send pics along to Joe and perhaps we can all hash out the details and challenges of designing/building this kind of boat in a thread dedicated to doing so…until then keep at it and think “weight savings”.
Hi Wade, Yes … John Marples does have a 10-foot Seaclipper trimaran. It can be built in either Constant Camber or ply on frames/stringers. But like Ian mentions, there is no hiking out … it features cockpit sitting & foot pedal steering.
Hi Wade,
Can’t wait to see your pics!
What pictures? Of my quickie trimaran with the inflatable amas? If so, my website has a couple of those. Don’t have many, anyway: I was saving my camera battery during the EC not knowing I would have to drop out after 27 hours :-(
Ian:
One of the challenges for me was coming up with a suitable rig that had enough sail area that could drive the three hulls with enough power but without overpowering the boat in a way that might cause pitch poling. It’s hard to fit more than a modest amount of sail area on a short dinghy. I tested some initial concepts but didn’t like them (windsurfing rig, bi-plane rig, etc.). I’m hitting the water with a balanced lug rig set up and tuned as taught by Michael Storer on his website. I bought his Goat Island Skiff Plans in exchange for using his rig ideas, and hope he’ll find that to be fair. When the dust settles from one perspective, I’ll already have my GIS rig ready when I build that skiff. The sail area is about 105 ft2.
Just looked up the Seaclipper 10 and it’s definitely a great example of a well thought out boat of the type we’re talking about…there’s some good pics and an overview from an owner here-
http://www.duckworksmagazine.com/11/projects/smiling/index.htm
in discussing all this I’m reminded of reading about the first meeting of WWII era German rocket scientists and their American counterparts after the war, where they all finally got to look at the guts of the machines they had been building…I believe it was Werner Von Braun who expressed the opposite of surprise when they all discovered that they had all essentially come up with the same thing while working in extreme seclusion and secrecy, as physics and the state of materials technology dictated what would work and what wouldn’t.
Obviously cobbling together a small DIY trimaran is more forgiving than trying to build guided missiles from scratch, but it’s interesting to note that as any boat gets smaller, the margins of what it can and can’t be shaped like and still perform begin to shrink considerably…one prime example being that at some point the very narrow displacement hulls with fine ends type favored by big offshore racers and seen in many sailing canoes/kayaks simply won’t scale down further and still be able to float a person and a sail rig and/or perform adequately (or even safely). In that sense designing a small boat of this type can present bigger challenges than a seemingly more complex larger boat might…it’s not at all as easy as just shrinking a bigger boat down.
Since this is after all a thread about John Marples and his designs, it would be interesting to hear his take on the problems surrounding this type of design and especially his take on the various strategies that might help overcome these design challenges…
my gut feeling is that weight reduction is probably the biggest bang for the buck available to the under 14-feet or so tri designer looking for performance…not that much different than with any boat, but in the case of multihulls the reduction in dead weight and wetted surface over a ballasted boat means less overall stresses generated as the boat interacts with the water, which means you can build lighter still…obviously there’s a point where you hit a wall where structural integrity can’t be maintained even using highest of high tech materials, but in my opinion very few boats are even close to exploiting the possibilities.
Here’s one guy who is thinking along the same lines- this hull in particular looks like a great candidate for an ultra-ultralight small tri concept if you are willing to sacrifice some durability for the sake of speed-
http://gaboats.com/boats/arrow14.html
It’s still a displacement hull and no matter how light will still probably face the possibility of sailing under when driven too hard, but at twenty pounds with a 2 1/2 *inch* draft, maybe not…besides, using similar construction a true planing trimaran light enough to do so regularly in real world wind conditions might be very possible.
David: Have you not considered dividing the sail plan into more but lower sails to reduce heeling? A cat-ketch or a cat-yawl? Sure, you lose some windward capability, but you can still close-reach, and how far is a 10 footer going anyway? :-) If you can extend the gap between main and mizzen — one mast at extreme bow, one mast at extreme stern with a boomkin — the backwinding of themizzen might be reduced slightly.
David- very true about maximizing sail area in small boats…which IMHO is another reason why keeping weight down is so critical.
There’s more than one way to skin a cat (or tri) and very often larger rigs with
their inherent weight and safety concerns reach a point of diminishing returns quite quickly, especially in a non-ballasted boat that you don’t want to have to pay careful attention to 100% of the time…but for any given sail area, in all but the lightest of airs the lighter of two otherwise identical boats will almost always see performance gains long before it gets so underbuilt that it can’t hold together.
I’ve mentioned it elsewhere on this blog, but it bears repeating- there’s a lot to be said for exploring more traditional multihull rigs like the crab claw or some updated version of it in lieu of trying to force a generic bermuda/marconi rig to perform on multihull boats that were never a consideration during its original development, all based on the common assumption that since it is (arguably) the best all around rig for monohulls and something of a performance benchmark, that it *must* be the best thing to put on a multihull.
I’ve built and sailed a number of models using a sort of delta/crab claw hybrid rig that tacks in an over the top manner similar to the Gibbons rig, and shows a great deal of promise…one aspect of it and similar rigs that ties in with the weight thing is that with a traditional marconi rig some amount of thrust off a boomed mainsail is always acting to drive the boat downwards, but rigs that can tilt to windward and spill excess air off the bottom can actually develop lift (albeit at the expense of forward thrust)…rather than trying to flip the boat over, in a gust some of the force is actually trying to lift the leeward parts of the boat (and the bow) *up*, and in normal operation and properly trimmed this lift can be used to effectively lighten the boat and reduce wetted surface…allowing a smaller sail to do the same work as a larger one, with less complexity in its design and operation and less stress on the boat and rig (and operator) to boot.
In my tests with models, I have never had a single boat capsize using this rig, and that’s with nobody on board to steer the thing through gusts or tend lines, in wind speeds that in scale were far beyond anything even I would be crazy enough to take a small boat out in.
On top of that, the non-bellied nature of this kind of sail makes it far more appropriate for a fast multihull, where even fully battened traditional fore and aft sails simply can’t get beyond the point where the boat makes enough of its own wind to make the sail luff on all points of sail (which with so much apparent wind all eventually become close hauled) no matter how tight you sheet it in or apply all manner of vangs and cunninghams and the like…perhaps it’s wishful thinking to think this is important in a boat as small as we are talking about here, but the ease of fabrication and simplicity of this kind of rig are enough to make it appealing even if the boat is never going to go fast enough to take advantage of the non-luffing aspect.
Hi John, thanks for share with us the information about the DC-3. Also your answers above were very clarifying to me. I am very interested in this design because I want a seaworthy simple boat for two or three people, that can sail in the open sea (not for crossing oceans), but also in rivers, that has a reasonable interior and that is simple to build and maintain. I am not interested in a speed machine, if it sails well it is enough to me. The only thing that a I don’t like very much is the CC construction. First it seems difficult to build the mould and then you have to use vacuum-bagging that seems complicated. Second the curved hull may be difficult to repair in case of damage. Third the hull seems to be very vertical near the top and so not very comfortable for the back. I think the CC construction is very good for a fast boat and as Marples said it speeds the construction. But I prefer simplicity and to have a boat that I can fix myself (I am not very handy). So I think it would be very interesting if there is a plywood version of the DC-3, perhaps using ideas from the Seaclipper 24 or with the addition of a single chine.
Regards, Andrés.
~3m DIY trimarans :
Marples CC 3m & Seaclipper 10, Kendrick’s Scarab 350, Gumprecht’s Drifters 12 & 12L (and Gumprecht 12′), Tryptique 12 ….
Hi Andrés,
I encourage you to strongly consider CC as a preferred method. I didn’t quite understand the beauty of this approach until actually building in frame/stringer. The hardest part (and not so hard at that) would be building the mold table. After that, however, creating the mold panels would go very quickly. But the best benefit would be the fact that the CC panels are rock hard. The word I most often hear that is used to describe CC hulls is “bulletproof.” And while that may be an obvious exaggeration, the point is that the extra hull thickness of CC, when combined with the fact that you’d be using less wood in the construction project overall, makes it a solid 21st century building option. Plus, if you ever needed to repair a CC hull then it wouldn’t be any more difficult than repairing a standard plywood hull. I just listened to an audio with Meade Gougeon and he spoke about how a boat built properly in wood will last for decades without losing any stiffness at all. He said wood won’t “micro-crack” in the way that plastic boats do, which is one reason why racing boats made with high-tech materials are retired after 3-4 years or so … they lose their stiffness. He totally convinced me that wood is still the best material for most boats … especially small trimarans. And if I ever build another boat it will be in Constant Camber.
Wade:
Split rig concepts are interesting. In hindsight, I wish I had built the boat in a way, e.g., with some alternative mast stepping options, that would allow me to experiment with split rigs. I’m too far into the build now to alter the design, though, without some serious hull surgery. I have my fingers crossed, but I’m hopeful I’ll have good helm balance. This boat should not heel much. I’m more concerned as to whether it will have good manners with respect to avoiding pitch poling.
The other concern I have is capsize recovery. But I have a two step strategy in mind for this, keeping in mind this is a small boat that will weigh roughly only 200 pounds assembled. This is a lot of weight for a dinghy . . . except I’ve got 3 hulls totaling 24 feet in length. As a first part of the strategy, I was going to run three stays from the top of my mast down to the bow of each hull. These emerge from the mast high enough not to be in the way of the lug rig’s yard. These are not needed for mast stability, but my plan is to string swimming noodles on these with the hopes that the noodle flotation will prevent a full turtle if the boat goes over. Next, I have a pair of lines stored underneath the side seats. If I hook these to the fore and aft beams and pull from a point 20-30 feet from the boat, I should be able to pull it over assuming the noodles are doing their job and the boat is sitting roughly sideways in the water.
Eric- Thanks for the post regarding available small tri designs…of the ones listed, the Scarab 350 and Triptique are closest to what I consider ideal as a sail trainer, as they both have a standard tiller/seating arrangement.
As I said before, the working with live ballast thing is imho a critical basic skill needed by anyone who intends to sail in water that is deeper than they can stand up in, even in a tri…besides, anyone who learned to sail in small boats as a kid knows that half the fun is pushing the thing to extremes and beyond- sailing it totally out of trim because three of your friends are on the bow, finding tops of blown out spinnakers in the trash behind the sail loft and rigging them up even though they are ridiculously oversized for the boat, capsizing just for the hell of it, etc…also there’s times when pure sailing has nothing to do with it and you just need a platform to do your goofing around on, and the boats out there designed with formula car-style seating in many cases just don’t allow this, much the same way that a formula car would be a poor choice for getting groceries or tailgating.
Like I said before, I get why some people like the car style seating, but my personal feeling is that one major advantage of the trimaran type is the huge amount of moving around/lounging room you get for any given length compared to traditional monohulls…dedicating the entire boat to pure sailing at the expense of this ability to move around, carry people/stuff, optimize fishing and diving activities and the like always seemed like a waste to me…might be hard to imagine for someone just bitten by the bug who will gladly grab any opportunity to get out on the water, but most sailors I know eventually get the itch to do something in their boat besides just sail for the sake of sailing.
To that end of optimizing space, the overhung F-boat style deck arrangement on the Scarab and Triptique is also a very nice feature, although the extra work involved might be a bit daunting for a first time builder- tris are always a bit more of a pain to build and maintain because there’s three of everything and tons of surface area to paint, clean, etc…but for someone willing to take on the added build complexity, those boats are very close to what I would personally consider ideal…the Scarab in particular has a very sexy, shrunken down bigger boat look that’s hard to resist.
Hi John. I will continue studying the CC method, but I am no convinced yet. I love wood. I have a Wharram Tiki 26 cataraman that is very simple and seaworthy, but I am looking for more interior volume without getting very big. I want something simple and seaworthy. May be something like the trimarans in the Ho Judson cartoons. To me, the stitch and glue method of the Gudgeon brothers is the more simple way to construct a boat and it is very easy to repair. But I don’t know if it is suitable for a comparatively fatter hull as the DC-3 and I think that Marples has no designs in stitch and glue.
Regards.
David:
RE: capsize recovery — Instead of pool noodles, which might have a windage and ugliness factor, I wonder if building one ama to enable flooding is a better option. A screw-out port in an ama-transom would allow easy floofing and rotation around the main hull. Then the water could be mostly spilled right out and the screw-in port replaced. (though if this is a tiny tri, then just standing on one ama and using a righting line or pole might be simply do the trick).
Hi Andrés,
The Marples’ Seaclipper designs are frame/stringer construction, which is very similar to stitch and glue overall. I understand your hesitancy to embrace Constant Camber. But keep in mind that the thicker CC hulls would eliminate the need for bulkheads. In the end, that would give you more room inside the craft … while necessitating less wood to construct the boat in the first place. That saves cost in building materials. And another thing that you may want to consider is that CC hull sections can be constructed out of thin panels created from 1/4″ waterproof luan. At $22-23 a sheet, this is far less than “marine-grade” ply at $70+ per sheet. The CC constructed boat can be built for much less and you’d get tougher hulls in the end. Anyhow, I just wanted you to consider your choices with as many facts as you can gather in order to access the options. Best to you as you decide on the trimaran that you want to build :-)
In Italy – I ignore if elsewhere – there is a development class for 10 ft overall boats. Very few limits incluce length, breadth and sail surface.
Find herewith attached pics of a 10 ft demountable tri. The plans although in italian and metric can be downloaded for free at the end of the article in the link in pdf format.
More pics of the boat can be found by googling the net for “triciclo” dieci piedi
Cheers to all, Stefano
http://www.diecipiedi.it/ns/vario/triciclo/triciclo.asp
Great link to the Triciclo Trimaran Stefano! I want to sail one :-)
It perfectly fits into the discussion about “dinghy” trimarans.
Stefano:
That’s a great link. The website on the little tri is very interesting. It’s motivation to get my little tri project done.
If anyone is interested in getting a fast, free translation of the triciclo site, the site Google Translate at
http://translate.google.com/
It’s an easy way to get a reasonably serviceable translation of the triciclo website itself from Italian to English. I don’t think Google translate will help with the pdf, though. But if the pdf has a url address, who knows?
To translate, enter the url of the website in the box on the Google translate page, and then choose your languages in the to and from dropdown boxes.
Stefano, go speak to an aviation engineer about flex ;-) all Boeing, Airbus etc aircraft wings flex considerably prior to creating lift, go tell them flex is bad, they are most scrutinised engineers in the world :-) let us know how you go
Have you ever considered making a tri with a Macgregor 26s. Its light, 1300 pounds. And is trailable… Maybe with Hobbie pontoons…18feet. make then swivel like your tri?
How do I get the plans for the dc3
Contact John Marples using his email address … located at http://www.searunner.com