Since It Is Still Locked - Multihull Plans Info

<center>From a different forum topic, now locked. </center>
<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”> this is a very stupid question
a friend has a cat, a hobby cat. it is not to scale. he just carved it out of faom. he likes it. but i kill him with my iom. everybody here says that multihull will be faster than monohul.
could anybody tell me where i could download plans, for a good cat?
and for the stupid question
what is an F48?
Cougar <hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>

Cougar, will try one more time here since the lock-out of the other topic happened just as I was posting, thus the message response was lost.

F-48 —What is it?
The F-48 is a multihull class that can be any boat with two or more hulls?.. Catamaran (2 hulls), Trimaran (3 hulls) Proa (usually one short and one long hull). The class is patterned after the Mini40 Class which has been sailed in Europe and the U.K. since the early 1990’s. Basically only a few rules control this open development class. It is controlled by overall length, overall beam, more than one hull, and limited to a specific sail area. Width cannot exceed 48 inches (1.2 meters), it can be no longer than 48 inches (1.2 meters) and sail area cannot be greater than 1400 square inches (.9 square meters). It is the smallest of the internationally (not ISAF) recognized classes The other class is the 2 Meter Class which also is sailed around the world.

There are two locations that provide for free downloads of plans (actually line drawings - not instructions) and several other places where line drawings can be purchased.

First - there is the site maintained by Alan Hayes in New Zealand - a “Kiwi” website from which line drawings of <font color=“blue”>“GHOST TRAIN” </font id=“blue”>can be obtained.

The other site belongs to Jean Margail in France and his <font color=“blue”>“WATER RESIST” </font id=“blue”>plans are available there.

<font color=“red”>Caution</font id=“red”> — either of these drawings, when printed full scale, use sheets of paper approximately 4 feet x 5 feet in size due to the actual size of these boats.

<font color=“blue”>“GHOST TRAIN” </font id=“blue”>is a U.K. design by Andy McCulloch one of a few well known British designers. It is a well proven design and continues to be pretty competitive around the world. Secondly there is <font color=“blue”>“PULSE” </font id=“blue”>- another U.K. design and former British National Championship boat. Designed by Mike Friend, plans can be purchased through the F-48 Class Owners Association. We also offer a 1 Meter scaled down set of plans that was recently completed by Jack Ronda from Washington and his photo recap is found elsewhere on this forum. It should be noted that <font color=“blue”>“PULSE” </font id=“blue”>has a royalty attached, (payable to the designer of $7.00 per boat built), and I can only furnish plans to US and Canadians. Others must contact Mike direct. Then there is <font color=“blue”>“WATER RESIST” </font id=“blue”>which is the French design of Jean Margail. His plans can be obtained for free or you can pay to have them plotted/copied if you have no access to a wide format printer/copier. Lastly, through Traplett Publications, you can purchase plans for <font color=“blue”>“SNAPDRAGON”</font id=“blue”>, which is a U.K. design by Mike Howell - and which has many boats sailing. In fact Peter Birch (Australia) who posts here has several sailing in their club and probably can provide answers to questions. In addition, there is a kit all the way up to a full sailing version of <font color=“blue”>“NIGHTMARE” </font id=“blue”>(Austrian design by Ernst Zemann) available through Ian Sammis - a builder in Kansas with excellent pricing. Available in a variety of different levels of completion. Another good and well respected builder is Anthony Wright (U.K.) but importing his boat is kind of expensive due to freight. If interested, I would suggest buying his hull, floats and cross beams, and obtaining sails and mast locally. Those are the only two current F-48 multihull builders that I can recommend. I understand (email) from some of Ian’s buyers, his hull kits arrived in just under 2 months from time of order. All are pleased so far with what they got.

Now - If you wish to use your 1 Meter sail and rig, take a look at the MultiONE as it has two levels of configuration. A “Sport” version where less sail area is allowed for stability reasons, and also a bit of lead on the daggerboard can be used to assist during training and learning to sail the boat. The “Open” class MultiONE has a few more rules! Just above this topic, is a link to the MultiONE pages where you can find the rules and further information.

As noted, printed copies of the plans are available through the F-48 MCOA and while they are a bit expensive the costs reflect the costs directly from local Kinkos’ print centers. Otherwise, you will need to have someone with CAD and a plotter do the drawings for you. Since “classified Ads” and sales promotions are frowned upon on the forum, you can email me and I’ll provide you with costs for whichever set of plans you may be interested in. They range in price of around $30.00 (US) - so if you download, remember you need some way to open/view the files and some way to print them. If interested, I can also send you an Adobe PDF format file which compares several of these plans on a single page. Again, just email me.

As far as the Hobie Cat “replica” for lack of a better word - if not to scale, the answer to his speed sailing would be evident. Even if built to some sort of scale, the model needs more lateral resistance which the asymetrical hulls of a typical Hobie 16 cannot provide - just as many monohulls require deeper keels. You know, it’s that scale effect thing?

Victor Products sells a catamaran, but is has too litle lateral resistance too, and so it suffers from performance. Kris Harig who manages the MultiONE site has one and made extensive modifications. You could contact him directly for more information. Finally there is my design for a MultiONE trimaran called <font color=“blue”>“IMPULSE” </font id=“blue”>which is also free. Just a side view of hulls, a set of cross sections for the main hull and the floats, and suggested “starting” location dimensions (still subject to some modification). This is the prototype that I have been working on, so I can’t give any kind of guarantee of performance yet. It is specifically designed for a foam build either as a plug with layup of glass over it and the foam removed, or as a foam core where the hull and floats are solid foam (except for radio area) which would weight just a bit more. I have no problem sharing that one, and it has been a basis for several posts about shaping foam in sections and then gluing up. Just want to be sure you are aware that it still is a prototype! It also can tip over and it can pitchpole. I guess it is important that these disclaimers are made in public so no further critical comments are made by others. Just a reminder to drop Ian Sammis an email and find out about his “kit boats”. Even though there is a cost, it takes a lot of the work out of building three (or two) hulls - especially if he is still making deliveries in a month or two. He even has Graham Bantock sails and rigs that can be supplied if you wish.

Good luck with your considerations and decisions. Would enjoy having another multihull from the Toronto area that would be visible on the water. Amazing at how much actually seeing a multihull does - instead of just talk.

Oh, none of the aforementioned designs will stamp out world hunger, or solve the middle east issues either - just a disclaimer I thought I should add in as well. Never can tell.

Hope this one doesn’t get caught in a topic lock !

i guess the size is important? you are saying that the hull are around 5 feet for best performance? i click on ghost train. and it seems like a good boat. but are all plans out there for tris? there are no plans for cats? you have me thinking. i have an extra radio that is doing nothing. maybe i build a mutlihull? but my iacc20 boats come first. and one is almost done. so the second comes next , and i do some research. either ghost train or if i can find plans for a hobby cat. I am not into racing yet. i will the IOM for now.
thanks again for the infor,
long live the cup

if you go multi…same here…I am already with a foot in! [:)]

Edit: spell aso.
if it isn’t broken, don’t fix it!

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by cougar

i guess the size is important?

but are all plans out there for tris? there are no plans for cats? cougar
long live the cup
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>

Cougar -

by now and at your age, you should well know the answer — that YES, indeed “SIZE” is important - especially based on all the SPAM that shows up in email “offering” all sorts of methods to increase … ohhhh ! Wrong topic ![:D]

The only free plans that I know of are for Jean Margails WATER RESIST.

Click on the British Flag for English version and take a look. It <u>IS</u> a 2 Meter boat, it is the only set of cat plans that I know of right now that has actually seen water under it. Peter Birch has some friends that sail some cat configurations in Australia, and he might be able to comment on the performance. I recall seeing some photos at one time if I remember correctly. PETER???

I also designed my 1 Meter so you could build 2 main hulls and assemble for a cat configuration, but right now I need to get the tri config done and make sure it sails well before heading to a catamaran design.

There are some benefits to a trimaran config - especially until you are comfortable sailing a multihull. The trimaran is a bit heavier and a bit more foregiving. I would not recommend a cat for a first effort.

On a cat …

  1. Hulls are very narrow, so radio gear usually has to go into a “pod” between the hulls. Kind of “ugly” looking!

  2. Cat is even lighter in weight than a tri of same size, so tacking is harder to keep from going into irons.

  3. Cat, being lighter is a bit faster IF you can keep her upright. Stability is a bigger issue than tri, because only one hull in water when heeled, and it takes a bit more wind to get windward float AND main hull in air on a tri. <font color=“green”>More time to get <u>out</u> of trouble on a tri </font id=“green”>and <font color=“red”>less time to get <u>into</u> trouble (capsize) with a cat</font id=“red”>.

  4. Tri only needs one rudder and one daggerboard. Cat needs two boards ( a single center keel is alternative) and also needs two (2) rudders. Steering is an issue because hulls are so far apart. Outside rudder needs to turn more than inside rudder, so some sort of “ackerman” steering adjustment is needs. Picture a car, where the outside wheel must travel further/faster than the inside wheel. Same principle.

  5. With two rudders, it is easy to turn rudders too sharply and basically put on the “Brakes” ! Works great if you are early to the starting line as you can come to a dead stop and with boat being so light you are accelerating sooner and faster. BUT - too much rudder in a turn while tacking and you can also come to a dead stop too!

  6. Less weight makes tacking in light air and waves a BIG challenge. Even on my big cat, I have found myself having to back up during a tack cause I 'blew" it ! Embarrassing - and VERY SLOW !

At the moment, that’s my list of issues and differences. I’m sure once I hit the “REPLY” button, I’ll think of more.

For stability, lead added to boards or center keel is possible to help learn to sail the boat, but eventually you will want to go with the “Unleaded” version, and will still need a lot of stick time to become experienced.

You can add moveable ballast, but with or without it and the weight difference will change the waterline lengths and displacements!

Doug shared photos of a cat configuration with a ballast system back in late 1999/early 2000 but all photos were only on land - none on water or sailing. Since it still isn’t available after nearly 4 years, I can only conclude (my opinion) the results weren’t as expected, perhaps because it could only move side to side. If you start using moving ballast like on a regular cat, you will find a need to also move it forward/aft at the same time depending on sailing angles. I’m sure Doug will offer to help you build your own, but if it were me, I would not spend time building something until it was proven in competition. While it “sounds” like it would work, the proof is in the results - as they say. You can always correspond with Doug if you want to pursue that route. Would still like to see the system working based on Doug’s claims - even if only on video.

Cougar - my recommendation is to use “GHOST TRAIN” lines and maybe build using household insulation foam (pink/blue/gray) and cover with glass cloth. Cut out areas for radio equipment. Use once piece carbon tubes for cross beams, and maybe even use your IOM “A” Rig for starters. Learn to sail the boat and learn what happens and how to avoid trouble (example - never go through a gybe down wind when main sail is completely out to one side. Sheet the main in about 1/2 - 3/4 ways, Gybe, then sheet out. Will reduce tendency to pitchpole in all but the heaviest winds.) Plus, the smaller rig will give you performance and less worry (relative term) about capsize.

Try to stay away from the beginner “macho” stuff of a full rig in strong winds. Better to learn to sail the boat “underpowered” and then add sail area as you get experienced. You don’t drive your car with the accelerator buried to the floor all the time - so why expect to do it with an ultralight multihull?

Just my opinions of course, and as before the usual stability claims are included by reference to previous posts.

Any other requestions - fire away.

If you decide to do “GHOST TRAIN” - let me know, as I have some drawings from a Brazil website that does a nice job explaining the build process. Will send you free via email. I had a girl at work translate, but she found it was Portugese - not Spanish. But you can work from the drawings.

Say … maybe that man of many languages (<font color=“red”>that would be … Wis</font id=“red”>) might be able to translate… ?[^]

<font color=“green”><u>EDIT: </u>added two drawing downloads</font id=“green”>

Here is a sample of the drawings from the Brazil site. As noted,they are easy to interpret.

Cutting hulls from foam sheets: [ smplacas.jpg]( Lemke/2004432051_smplacas.jpg)

“Pin” the hull to allow spinning while laminating the glass cloth: [ smlaminado.jpg]( Lemke/20044320552_smlaminado.jpg)

There is a mini40/F-48 design called Kwika that is a cat. It apparently is quite quick. Some of the members at our club use to sails cat, myself included, but found that in our normal wind range could not compete against the tri’s. Cat’s need to change down rigs earlier than the tri’s therefore horsepower is just not there.


Cougar, contact Ian Sammis: he built several cats before he started building the Nightmare tri.
He is also experimenting with a movable ballast system as I did on a F48 cat. My system moves side to side and fore an aft. I’m not producing it because it is very expensive compared to a foiler and is not as fast or as stable.
But a cat with a movable ballast system IS more fun than a foiler from a boat handling standpont-it is tricky like any F48/mini 40 but the PBS adds lots of power and is loads of fun to sail with–but you absolutely will capsize /pitchpole even with a PBS. And the boat MUST be designed for a movable balast system or else it won’t work right-depending on weight.
Talk to Ian about his experiences with both the cat and tri-he has actual sailing experience that could be beneficial to you as does Peter Birch in Australia-with both types as well.

Doug Lord
–High Technology Sailing/Racing


I cant speak Portugese…but I could take a look…for sure I can do something…getting more and more interested… [;)]

if it isn’t broken, don’t fix it!

tela is cloth, espuma is foam, intiende?

<font color=“purple”><center><font size=“4”>ED …MY MAN !!!</font id=“size4”> [:D]</center>
<center>Thanks !</center></font id=“purple”>
The one area that I am having problems is how he is mounting and allowing movement in his curved boom. I understand the concept, but again, a few words might help. This is all he shows for the boom to mast gooseneck fitting. It “seems” he has some material (maybe solid nylon ?) inside a tube to which the boom attaches. I can understand how it moves up/down, but the side to side seems like it would be a lot of friction, and limited travel to the starboard side of boat. Would you mind helping on that one please - if you can?

Mast/Boom Details: [ smboom.jpg]( Lemke/200444111652_smboom.jpg)

Main Boom: [ smmainboom.jpg]( Lemke/200444112459_smmainboom.jpg)

The fitting is labeled EJE - which I don’t understand. Any help is appreciated. Just doesn’t seem like it has enough room to swing very far to starboard (in drawing). I might be missing something however.

if you can send me a larger image,maybe i can translate it. some of the text are too small to be readable. eje is axle or pivot, botavara is boom, botavara mayor is main boom,anclaje de la vela is sail attachement point

OK - will take a look. As I recall, when viewed in a 1:1 ratio at 72 dpi, the image is huge - like maybe 20 inches or so. Will try a few different sizes to see which is easy to read, yet not so big to create download issues. Are you on broadband/high speed net - or dial up?

i can use any of them,from home and work

<center><font color=“blue”><font size=“4”>HEY COUGAR !!!</font id=“size4”></font id=“blue”></center>

Wis sent me these photos that he couldn’t post. I forgot about the catamaran that Anthony Wright (U.K.) builds.

<center>Anthony Wright’s CHEETA - Mini40 Catamaran</center> <center></center>
<center>Anthony Wright’s trimaran MACHETE:</center>

WIS - just a note - for embedding the photos I did have to shorten the long name for the trimaran too - it was too long!

and Ant’s url is :


<font color=“red”>Edit: for best use: only with IE ; i do have troubles with a a mozilla-engine browser…Netscape user; sorry![:(]</font id=“red”>

if it isn’t broken, don’t fix it!

ok guys
you got me
i will be building a cat. ilike wis picture of his cat
now the question is . what special stuff do i need. a cat is what i want
and with the help of dick and matt. and maybe even wis. i should have a cat next summer( i dont know how long they take?
long like the cup<font size=“6”></font id=“size6”><font color=“blue”></font id=“blue”>

Cougar -

God help me if I don’t “SPECIFICALLY” remind you that cats tip over easier than trimarans. Doug would be s-o-o-o-o upset ![B)]

A few considerations and decisions …
Buy or build?
With/Without foils?
With/Without moving ballast?
Hollow hulls or glass over foam?

If you elect to go with the cat at 1.2 Meter size (as pictured) - don’t worry about rig or sails - use the set from one of your IOM boats as a starter set - will keep you out of trouble. If you decide on the 1 Meter boat, swing down to the park and watch the guys there with their boats. If you need email of a contact - let me know by email and I’ll get you in touch with one of the multihull guys. (Toronto area)

A fast build for first effort is glass over foam and Jack Ronda in Sequim, Washington (red trimaran) can give you hints and tips too. Contrary to any posted info on this site, other than Anthony Wright - there is no other producer of cat config multihulls. All are “Home Grown”.

Before you dismiss Ant’s boat, I think a set of his hulls (to purchase) is very competitive - and probably less expensive than making your own. If the cost to ship isn’t prohibitive, give that some serious consideration, as it will eliminate a lot of work to make two identical hulls. The specifications for Ant’s cat is as follows:

1.2 mtr. x 1/2 mtr. (Mini40)
approx. 2 kg weight (4 1/2 lbs)
80 GB pounds - $147.26 U.S. or $192.82 Canada
Includes drawings for completion. Suggestion- get mast and sails in Canada - it will save freight cost, but sit down when you ask how much for freight. Too bad Wis isn’t close by, freight for two would probably be the same.

Well, there are some starting questions and decisions for you. Good luck.

Suggest a good, fast winch - so you can “unload” your sails in a big gust. Also a "chase boat and a chunk of foam for mast tip That will keep it on the surface so if no chase boat, at least it will blow/float to shore.

Or just go twin rig, then you will be upright long after the tri’s have gone home!

Luff 'em & leave 'em.

One of the things that is very important, should you decide to use a movable ballast
system, is to use it ONLY on a boat designed for it! Any other boat-cat or tri either the weight will be severely limited or the boat will float too low or both.
Much has been said about cats being less stable than tri’s and the reason given is that they are narrower than tris; why? My D4Z Power Ballast System Cat(not presently available-but will be again) is 33" wide with a four foot trapeze Power Ballast System -and was designed for the extra weight. So in light air it tacked on a dime because the hulls had overhangs with the PBS removed-and when the weight was added-more than doubling the righting moment she floated perfectly with the windward hull just kissing.
Cats DO NOT have to be designed as narrow as most are or even as narrow as mine was: if you look at a modern trimaran-model or fullsize they go their fastest with the mainhull just kissing the water(slightly clear) that is, they are sailing on one hull LIKE A CAT! And right here Peter Birch said his tri’s tacked very well which MUST mean even when they are flying the main hull while sailing like a cat! I know that my 68" trimaran tacked on a dime EVEN WHEN FLYING THE MAIN HULL!
So why not make a cat as wide as a tri? NO GOOD REASON! Look at Yves Parlier’s newest 60’ cat designed to compete directly with the 60’ ORMA trimarans-it is 50’ wide!(corresponding to a 40" wide F48). No, its not the daggerboard position either (as far as tacking goes)since if they are designed properly it DOESN"T MATTER if the board is on the centerline or outboard. again as far as tacking goes.BUT when going to weather one board is definitely more efficient in developing lateral resistance UNLESS there are other factors involved.
So consider a cat but also consider thinking “outside the box” if you don’t automatically want last place when racing a tri…

Doug Lord
–High Technology Sailing/Racing

Interesting idea - but ISAF hasn’t (to my knowledge) ever made a ruling on this issue as yet and it could get messy in fleet racing. Perhaps why we don’t see real beach cats using the concept.

Downwind, twin masts, sails out to each side — what tack is the cat on - port or starboard, and who will have ROW at any compromising (crossing or mark rounding) situations?

To be honest the last thing you want to do is have a rig on each side, and in reality its pretty hard to do intentionally…

Luff 'em & leave 'em.