trimaran plans?

Hi to all

Been awhile since I have posted here.

Anyways a friend of mine is interested in building a trimaran. He was thinking of a cat but figures it may flip pver to much so wants a tri. Also no rescue boat where we sail.

Are there any plans online for these? Did try a search but did not find any (may have done it wrong)

Looking for a very basic tri plan nothing exotic. And if the plans are free that is even better

Anyone have any leads?


Hey Jeff -

try the “multihull” section of this forum - and start with topic “Trimaran Plans”

Currently I know of 3 free ones… GHOST TRAIN and WATER RESIST (both F-48/Mini40 size) and my small set for a MultiONE called IMPULSE that just hit the water this fall.

For around $13.00 you can also order a set of line drawing for SNAPDRAGON an F-48/Mini40 through Traplet Publications, and I have a set for PULSE which is in either 1 Meter or F-48//Mini40 size at approximately $35.00. (These are full size 3’ x 5’ drawings and also include a royalty payment to designer Mike Friend)

Remember - most are line drawings and cross sections - not “building instructions” - and when printed to full size they require a wide format priner capable of 3 foot x 5 foot sheets of paper!

Regardless which you choose - if you are an experienced builder you can build one of these using the drawing and cross sections along with monohull guides such as the US1Meter construction tips. Don’t want to plank? WATERESIST, PULSE and IMPULSE are all designed and can be built as glass over foam for a quick, easy build. Any questions - email me. I suppose you can also use Ernst’s plans that he has posted on the web as well.


<font color=“blue”><u>EDIT\ADDED:</u> I was just thinking of a possible “hybrid” construction method … one using glass over foam AND balsa plank. Basically you can shape the bow and very stern of of the main hull … and the full lengh of both floats using foam, and then only have to plank the mid sections of the main hull to keep it hollow for winch, rudder servo, mast base and keel! In a sense, you are simply gluing up the balsa planks in a “U” shape for only the area of the hull that carries the radio gear and where the mast and board connects. The remainder of the hull is simple house insulation styrofoam (extruded - not expanded) that can easily and quickly be shaped by coarse files and sandpaper - and then covered with glass. For any areas where shrouds attach or cross beams attach - just drill a hole and glue a piece of wood dowel of sufficient size into the hole. Then attach your shroud or mount your cross beams as needed to these reinforced points.

This will give you a very quick and easy build (and inexpensive) set of hulls. No need to build a nice plug, then a nice female mold. Just get the foam and balsa smooth and shaped, add a layer of glass outside, and a light layer inside the balsa section, and fair off the exterior and paint. Again - as noted - unless you are racing in Europe, a slightly heavier build using this technique will be hard to distinguish from a much more expensive lighter one. It’s an inexpensive way of getting started and trying out a multihull with a minimum investment. Use a standard 1 Meter rig and you can see how a lighter weight boat (without lead) will perform. You can always build a taller mast and bigger sails later - and if there is a need for even more speed, then later on you can decide to build or buy using carbon or Kevlar! Just another idea for building an inexpensive platform of either 1 Meter or F-48 size. </font id=“blue”>

Do you have the shadows posted anywhere. It could be built if they had the shadows. Not enough information to build a model with what you show. I still haven’t received the plans you offered for the hulls you sent me. I sent my address as you requested.

Here are mine for the <font color=“red”>MultiONE</font id=“red”> “IMPULSE”. In fact, it is sort of a documentation of some of the building step details of the trimaran.

Hi Dick,

Thanks for posting the constuction photos of your Impulse. This is really helpful from a beginners point of view. I’ve been lurking around on the list for a couple of months trying to figure out how to start construction of a trimaran. This really gives a step by step breakdown of the construction sequence. Can you give the newcomers an idea of how many hours that you have invested in the project? I’ve noticed alot of discussion about building plugs for making molds of the hull. Do the weight savings and corresponding performance increase justify the increased building complexity of building a mold first instead of just covering the foam with a layer of fiberglass? Another question that comes to mind is this: Once you have the two hull halves constructed, how are they joined and the seam made waterproof? Is it a simple matter of gluing the two halves together using the foam formers shown in the photos and covering the seam with another layer of fiberglass? How many layers of 1/2 oz cloth are necessary? Are your sails and mast scratch built? If not, where is the best place to get the hardware needed to complete the boat? I’m getting ready to start construction on a Freight Train trimaran. Received the plans and they look very complete. Probably detailed enough for a first time builder to complete. Sorry for asking so many questions. Thanks in advance for any help that anyone can provide.

Mark Aulfinger

Hi Mark - will try to take the questions one at a time.

  1. Time involved: I never kept track, and there was a lot of procrastination on my part. Would think of something and never get out in the garage to give it a try. Boat was done over about a two year period (excluding winter when too cold in garage). But the foam cutouts and glue up of the small pieces to form a full hull took me just over 3 hours. Obviously if I left the foam inside, You could add another 2 hours total to get the hull and floats shaped and covered. Jack Ronda in Washington did his “PULSE” 1 Meter in several weeks as I recall. Just depends on how much time you have available to devote full time. During my build, I was also working on an F-48 r/c size, and was involved in horse training and showing which also took a big chunk of time away from building - plus work and grandkids !!! Whew. All in all, I have (maybe) 160 full hours involved spread over many months and in minutes and hours as I worked on different things. My design of the boat’s name for instance took me about 1 hour on the PC using Corel Draw to do the graphics - and would be included in the above estimate of time. I know of one German builder who did a box section F-48 size trimaran in two weeks…

  2. The time to build a hollow set of hulls is involved in the final fairing and finish. I see no benefit in making a mold first unless you are going to build 3 or more hulls. On a glass-over type of build, you will be putting in the same amount of time to finish the outside of the hull as you would making a plug. Add in the time to then build a female mold and you probably double the time to finish as the inside of the female mold needs to be faired and polished to make sure the hull layup is smooth. Yes, there is a weight gain leaving foam inside - but for first efforts, and without other “hollow” boats around, you may not see the difference. It is definitely a quick method. You can do what I did - cover the foam in plastic packaging tape and layup a 4 oz. and a second layer of lighter cloth and then peel off from the packing tape covered foam to end up with a hollow hull. Once you start racing, you may want to opt for hollow hulls if everyone else is doing it. Locally - if you can get friends to agree to foam hulls and will have a one-design feature going and all will weigh the same.

  3. I joined my hull halves using 1 inch wide glass tape and faired/filled where the tape lapped over the hull sides.

  4. As noted I used a layer of 4 oz. cloth and a layer of 1/2 oz. to provide a nice small weave finish which didn’t take a lot of resin to fill the weave pattern. I laid in a second internal layer of 4 oz. where the keel trunk is located and it runs from gunwale to gunwale. Also a small strip of the 1 inch tape where cross beams attach. If you grab the main hull and squeeze the sides, they WILL “oilcan” so unless they fail I feel I have just the right amount of strength and don’t feel it is overbuilt. For an F-48 with foam inside the same would be fine. If you want hollow hulls on an F-48 I would probably go to 2 layers of 4 oz. and one of 1/2 oz.

  5. Sails and mast were scratch built. I used SAILCUT software to make up sail patterns and as noted in photos, built my sails out of paper first. These became a pattern for the ripstop nylon fabric. It is a coated 1.5 oz. cloth. I made up a metal sail building board out of aluminum to help with the camber and seams are just taped, although leading edges were sewn. I don’t think the taped seams will open up from all that I have seen or heard. You can also use mylar drafting film for the sails.

  6. Mast was also scratch built. Actually it was recycled. I hooked up with a cross-country ski pole manufacturer and they are willing to send me all the broken poles I want. Usually tips are broken, and the mast is a tapered carbon pole and is very stiff. I don’t feel I will need to add spreaders to stiffen more. In fact I took two poles and made up a mast for the F-48 which is 8 feet long. (Need to trim down a bit) - but that one will probably have spreaders. Right now it is holding a set of sails from the Marblehead class.

  7. Hardware can be home built using aluminum or brass and screw eyes. Other parts and supplies can be found through the list of AMYA suppliers. I am partial to Great Basin (GBMY) as they have good prices and are quick to ship. Also email Ian Sammis as he may be putting together sails and rigs for his F-48 boats and might be willing to add on to his order. I recall he is using Bob Sterne mast and sails. Another option, once you have designed your sails is to send the x-y coordinates off to Climate Boat Works. Peter will laser cut you your panels and you just assemble them. Very accurate method of cutting panels.

Do visit the AMYA website - and also check out the US 1 Meter Class pages - they have a great downloadable manual for building boats. It will help a lot, and much of the monohull info can be used for a multihull. Also - FREIGHT TRAIN is a great boat, but has a little bit too much underwater surface for my liking. One nice thing is that it is a proven design. Be sure to build it as light as possible - especially the main backbone of the boat. Stay light, and if you build using balsa - you only will need a single layer of 1/2 oz. glass on exterior. Be sure to waterproof interior. The balsa and glass will be plenty strong, and you can always reinforce around the keel trunk and cross beam (wing) attachment with 1 or 2 layers of the 1/2 oz. cloth just to make it a bit more sturdy.

Finally - feel free to post questions, as we do have a few builders, sailmakers and radio people here on this site that are willing to help with answers. Good luck - keep us posted on your progress.

salt_water_frog@yahoo.comI started out with the idea of building a ‘tri’. My orginal thought was to have the main hull when turned upside down would be the outside floats. After sanding and sanding and sanding I decided to build a ‘cat’. I made a plug then the mold and to date have taken 4 hulls out of the mold with each one getting lighter. I am going to try a ‘free standing mast’ along with one rudder and daggerboard in the center compartment which will house all the gear. The sails have arrived from England and now I ma in the process of selecting a servo and winch. Any suggestions???

There is a gent over at RCU who is offering free plans of his Nightmare designs:

One of our club members is working on the plans now for a spring project. Am sure looking forward to seeing this sail on Xi Hu!


The “gent” you refer to is Ernst Zeamann (aka “Idealist”) who has less than a stellar reputation in the r/c multihull world for a “few” issues of selling boats but not shipping for a long, long time. Some even threatened legal action.

Now (as I understand it) he is dumping free designs on the internet and letting others build. Not sure how good/bad his designs are as I’ve never seen any national racing results from Europe or U.K.

Good luck if you decide to follow-up and build one. His earlier designs were very thin in bow and did not have enough buoyancy. Perhaps his plans have improved?

Depends on your budget.

  1. Cost
  2. Speed of winch
  3. Torque (holding power) of winch

Almost any mid-size servo can be used for rudder, since the rudder is balanced and once it starts to turn, the part of the rudder in front of rudder post helps/assists in turning the rudder that remains behind the post.

Best choice - the Guyatt series of “smart” winches - they have power, speed and great reliability. Used by many in the IOM community as well as other big designs. Great reputation and Rob (owner) is easy to contact for any technical information needed. This is a “drum” type winch - not an arm type. Futaba also makes a drum type winch which is nearly as spendy. Reasonably good reputation and probably one step below the Guyatt winches.
Both Futaba and Guyatt drum winches run in the $150 price range.

Don’t consider the smaller and less costly Hitec drum winch, as it is too slow to react to multihull sheeting speed needs.

Hitec has a 1/4 scale arm winch - the 815BB - which is both strong and exteremly fast. If you buy from ServoCity, you can purchase several modifications - like 180 degree arm movement or continuous rotation. I’m not familiar witht he continuous modification as to speed - I think I read where it was three turns, but could be wrong. Since it is based on the 815 arm winch, power and speed should be similar. Cost is in the $50-$80 range as I recall.

Note - one issue of the arm winch is enough clearance below decks for the arm swing. On my MultiONE trimaran (1 Meter) I had to position arm above deck. The continuous version wasn’t available at the time of build so I would guess it might be able to be fitted with a drum instead of an arm.


Interesting. I didn’t know this background so thanks for letting me know. As mentioned, one of members got the plans & is redesigning them to do as an experimental rig. We’ll let you know how it turns out.


I am new to this forum.
Actually I have never built a radiocontrolled sailboat before.
But I thought for myself, if I would like to build a sailboat it needs to be a trimaran.
Therefore I am looking for a free selfbuilding plan now.
Would you please be so kind to tell me about the different problems of the different designs, which are available for free on the net?

And one more request, if I may:
Would you please tell me all possible and interesting links and other forums, where rc-multihulls and especially the issues of trimarans are discussed?
Also, if there are old discussion boards still online, which have been discontinued - and maybe even why they where discontinued.

I am looking forward to receive many answers.
Thank you very much.

OK - so nobody seems to be interested to answer my questions.

Right now, there only seem to be real Mini40 designing and building activities
in Germany and Austria:

Unfortunately I don`t understand German, so I can only look at the pictures and try to understand, what they are doing and why they are doing it in that particular way.

Why does it NEED to be a trimaran? Your name “disabled” makes me wonder if you are under the impression that a tri is more stable and would be easier to sail. An R/C monohull is normally self righting. A cat or tri will capsize if a gust hits and stay that way. You need a rescue boat for multi hulls. If you just “want” a tri then disregard this post.

I “sorta” agree with Don -

if this is your first build of a sailboat, a trimaran (or cat) is a MAJOR undertaking. You are essentially building three hulls (two of one design for floats; one of another design for main hull) which multiplies your work effort times 3.

Start with a monohull - maybe a hard chine JIF65 for a start with only four panels for the hull. The lead will slow it down, but will also keep it from being tipped over. Learn to sail first, get good with thumbs, trim, set-up, etc. Then decide if you want to move on to a multihull. Not only are multihulls for experienced builders - but they are for experienced sailors as well.

My “sorta” disagreement comes in that nothing prohibits a keel with lead on it as a “training wheel” for a multihull - but again, a multihull sails so much differently than a monohull, you need quick thumbs on radio sticks, and quick acting sail winch as well. Adding “lead” defeats the benefit of a multihull, and adding a foam float to top of mast will help - but as Don notes, plan on having to get to the leeward side of the pond to rescue the multihull if it goes over on it’s side. If it goes over and is upside down, plan on wading out to it, as your mast will hit bottom well away from shore.

Multihulls ARE VERY STABLE platforms - either right side up, or upside down. Keeping them rightside up is the challenge.

To translate websites to English, go to and paste the URL of the website in the correct spot, choose the language and Voila` (that’s French), it is translated! Or rather, is understandable… sort-of :slight_smile: .

@ hew565
Thank you very much for that translation-link!

@ Don
When I choose my “nickname” as “disabled” I wasn´t referring to the boats I´m interested in, but to myself - as some kind of british humor. I´m simply sitting in a wheelchair due to a heavy accident when i was a kid. Therefore I consider boats with lead on their fins as something “chained to the ground”, which reminds me to much to my own situation -
sorry, but I can laugh about that - by now. -

And because of my own situation I always need a second person to guide me around, so it is not a big deal to send this helper to turn my boat the right side up again if it flips over.

I really want a good trimaran and I want to learn to sail it as good as I can.
At least I have skillful hands I can use to my best - building a model or sailing it. -
And I got nothing else (useful) to do in this world.

@ Dick Lemke
I think it is a sad fact that you as the class secretary of the mini40class - or Formula 48 class for the USA - tell me to build a keel boat, instead of giving me proper advice how to build the best possible multihull.
Sorry, if I get to personal - but it appears to me as if you have given up already. This sounds like pure apathy to me - but it is not my intention to offend you.
It is just a pity that you do not work together with Ernst Zemann (Idealist) - as he continues his developments and research, no matter how long it takes.
He is still providing free selfbuildingplans in - and you should stop discrediting him (only my personal point of view) - no matter what has happened in the past.
Maybe he is not a good business man - and maybe he never will be, but I believe he is a good designer and a good teacher with lots of patience.
He has given out almost 60 free selfbuilding plans of his Nightmare Mk.VII by now. There are also several US-citizens amongst them, as far as I have understood the free educational program he is doing in that other forum.
Please give it a try - and forgive him - no matter what has happened between both of you.
It happened in the past - and the past is already gone. But future is ahead - and we can decide, how it will be.
Please take this “advice” from a disabled man - because I am one who has more to forgive than most of you.

Dear Disabled,
I am coming to the defence of my friend Dick Lemke whom I have never met, but have the greatest respect for, based on the help and knowledge he has shared, with so many forum members and others in our hobby, over so many years.
No one has supported the model multihull movement more that Dick Lemke.
He never shows his frustration when answering the same questions as asked over and over again as happens on these forums.
Newcomers seem not to use the search function to find out what has gone before.
When you note the number of posts that Dick has made you may have some idea of the contribution of this fellow.

I have seen some of the frustration and grief caused by people in this and other forums when contracts and promises have turned out to be unfulfilled and people have been ripped off.
Any advise given by Dick is designed to prevent this happening again.

As for helping you either build or buy a multihull I am certain that Dick would be the most enthusiastic supporter you could find if that is your decision. (End of defence address.)

However, none of us here want to minimise the requirement for skill, patience, dedication and perseverance in building and sailing any kind of model multihull.
Quite frankly they are pricks of things to sail. :slight_smile:

If you have never sailed a radio yacht before then you are in for a frustrating time.
We are all here to support you and wish you well.
If you would keep us informed as to your progress we would be grateful.

As for your question posted here and on the R/C Universe site as to why you can not purchase a kit or a complete ready to sail multi, I can answer that quite simply… economics.
The market is so small and the costs of production of a “proper” multihull so large that only a fool would consider it as a commercial venture.

If you want to purchase a ready to go boat then there is one second hand Ghost Train I know of that may be of interest.
Trouble is, the cost of transport, as it is currently one piece.
If the beams were cut for transport they could be reassembled at your destination or even better the boat made collapsible for your convenience.

Now sir, the ball is in your court.
Help and advise is available if asked for with a little courtesy and humility.
We have all been where you are in this hobby.
Best wishes.

thank you for these informations, but there is no need to defense Mr.Dick Lemke - as I did not intend to attack him at all. I´m just saying it may be “time for a change” here as well.
I have used the search function, before I started to write here at all.
I can see also that frustration and grief can keep a person from fulfilling his dreams. But (false) hurt pride may also stand in your way to fulfill your dreams.

I can only repeat that human beings can make mistakes - business- or design-wise. But they also can learn from these mistakes and change what did not work.

A good designer may never be a good boatbuilder -
a good boatbuilder may never be a good designer -
a good salesmanager may never build a boat -
and a good boatbuilder may never sell anything.

However - I am coming to the defense of Ernst Zemann - the Idealist - who told me he allways wanted to be a designer and teacher in boatbuilding. -
Not necessarily a serialproducing boatbuilder, nor a distributor of many rc-multihulls.
He told me, he wanted to get the useful knowledge and share that knowledge with everyone who is interested.

And he also told me, that he was tricked almost nine years ago by false informations given to him by US-modelsailors, which caused a financial damage of about 4.000 US-Dollars to him. While trying to build some Mini40 trimarans, he had to make up that financial damage - which unfortunately did not work out.
And then the same persons who had caused that financial damage to him, attacked him in a very mean and evil way because he was unable to deliver in time.
Please think about his frustration and grief - in relation to Dick Lemkes frustration and grief.
But the Idealist made his way through and learned his lessons - in design and in business. The result of this is the Mk.VII design.

The free selfbuildingplans of the “Nightmare Mk.VII” from Ernst Zemann - Idealist - can be found here:

Please give it a try! - That is all I am asking for.

PS: It has been proofen by at least two experienced german rc-sailors and modelbuilders that the “Ghost Train” design does not work properly. Major changes need to be done, to get the boat sailing well. Which is as much effort as designing a completely new boat - or building another design from scratch.
I am not interested in a “Ghost Train” at all. Sorry, but this had to be said.
I`m staying with the Mk.VII.

OK - I guess it’s time once again to make “facts” known - from the “other side” -

1> Mr. Zeamann was the person who promoted his own design and boats. Completely built, as kits or as parts. He sold a “kit” to Mark Baldacchino (who, with his father in Arizona, strung together a few impressive “National” championships in other classes) - mentioned so as not to be taken lightly. Mark had one hell of a time getting the boat he paid for. It was an offer by Ernst, with an acceptance by Mark and no product arrived for some time to fulfill that “contract”.

2> Mr. Zeamann sold a boat, then several parts to a Bill Hojnacki in Hawaii, who also had a hell of time trying to get what he paid for. He eventually purchased Mark’s multihull (Mark by then had a baby on the way) and sailed it for several years in Hawaii before selling/shipping to Australia.

3> Ian Sammis (an engineer with Cessna aircraft) bought parts and bits and pieces from Mr. Zeamann and had issues getting the boat or parts quickly.

4> Lincoln Rowley ( Eastcoast USA) had some dealing with Mr. Zeamann that weren’t helpful and most troublesome.

5> Mr. Zeamann had a young fellow in Washington (state) create, develop and publish a website to sell his boats. The promise was a free boat. To my knowledge the website appeared, but the boat didn’t.

Keep in mind - ALL of the above were based on Zeamann’s claims to “SELL” a boat. When thousands didn’t beat down his doors to purchase his product, he claimed we (forum members) led him astray with false sales numbers/information for the U.S. market. When was the last time ANY company accepted sales and marketing information from the Net? As for me - Mr. Zeamann never responded with any compensation as his “sales and marketing consultant”. Why? Because I never was one, not did any of my responses EVER indicate I was one - nor did I ever provide even “suggested” numbers. Ernst did no marketing research, and blames others for poor or no information. At the time, I encourage Ernst to build and sell from the “Shelf” - instead he decided to take money now, and build later. No one wants to wait 6-8 months to get a boat they paid for - they want it shipped on receipt of the money. Ernst elected NOT to do that.

If the GHOST TRAIN was/is such a poor design - explain why variations of the design still hold a great number of European or U.K. National Championship titles - while none of Zeamann’s designs are “race proven”? Since Ernst (and I) have been at this game for nearly a decade (I began in 1999 - Ernst a year or two later I believe) please forgive my “APATHY” as you call it.
[/SIZE] has been around long enough to see my efforts - a website for multihulls, nearly three years of an electronic “International” multihull newsletter links to the two “FREE” plans on line (GHOST TRAIN and WATER RESIST) my own 1 Meter design (IMPULSE) provided at no cost via the web, and dozens of responses to questions - technical ones as well as suggestions and recommendations to new builders.

So for me “not” to take your comments personally is difficult to do. Quite frankly I gave you my honest and heartfelt advice. I suggested a keel boat on which you could both learn to build and learn to sail. It was to provide you something you seem to lack - experience! Once you can build, once you can trim and once you can sail in light wind or heavy wind, only then would I recommend a multihull. BUT - that was my opinion and recommendation. I furnished you with the above “facts” regarding Zeamann and you can do a search on his name and find what his German “peers” think about Ernst — those having been around the multihull scene for more than a year or two. I stand on my opinion that Ernst was the only person responsible for his production failure. To point to me or others in the model multihull community as an excuse is an example of his failure to accept the criticism he deserves.

What “MK” number is he now up to? If he keeps improving his boats with every model (design" release - what does that say about the guys who bought or built to design # MK-I ? Poor design? Poor performance? Poor handling? The questions are many - but I no longer dwell on him - until I see his designs in the race leaders at major multihull races in France or Europe. Ernst has done nothing to gain credibility in the multihull community (in my opinion) so quite frankly, use his designs, build to them, but don’t come to a multihull community on-line and ask for free advice and then criticize the opinions or suggestions you get.

You seemed disappointed when there were no responses to your request for free plans or kits. When you finally were advised “WHY” there were no production builders, you kept asking on other forums. I do not wish to debate the issues, it’s been done in the past. I don’t care what you build, whose design you use, or if you race or not. I’ve got my three (multihull) boats consisting of two F-48 class and one MultiONE class boats, and I am just completing the fourth of five RG-65 monohull builds. In addition there have been a “few” other commissioned builds of 1 meter and 366/600 boats along the way. Thus, I don’t take your posts personally, but I certainly do take exception of your views on this area of radio control model sailing.

Just get his plans, build the boat, post a few photos and be happy. I would suggest you just ask him your questions about how to build, rig, adjust and sail his “creations”. Surely one would expect that from any designer of a boat, regardless of the class - or the design.

I wish you well and look forward to your completed multihull photos. I will debate/discuss on this issue with you no further.