High Power Very Small Tri(s)-10'-14'-why not?

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Why would you say that? Just kidding. Thanks for your post.

 

There are many reasons for "why not".

The primary reason is ease of use. Even a 10 foot long "square" multihull cannot be trailered without folding ot de-mounting. That's added hassle most people don't want. Even if you have a spot in a dinghy yard the spot will not be wide enough, so it will be the same fold/de-mount hassle even if you have the yard spot.

The next biggest reason would be price. The multis that are selling best these days are really inexpensive. This sort of design would not be.

Another reason would be the limited ability to take others sailing with you. Back when I worked in the Hobie shop we had a difficult time moving 14s since they were really singlehanders, and with 2 up they didn't sail very well. Almost every 14 we ever sold was traded in within a year for a 16. Beach cat sailing is a way of life, not just sailing speed.


Seems you have asked why not, without saying why. Seems the folks at Hobie and the other beach cat producers have not found the need for such a craft in their market research.

Why are you wasting time talking about this, not designing it, while at the same time not designing the most important boat of your career? Seems you've abandoned that one after the brass plaque was affixed to the model base.

 

I think thats a Capital Idea that you have to make small cheap production boats that the Average American can afford to tow behined their GM (Goverment Motors) Automobile.

You may be interested in producting some of these.

http://www.boatdesign.net/forums/multihulls/flying-trimaran-33428.html


What do you think?

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I don't think it fits within the parameters of this thread, do you?

 

As long as someone has the time, inclination and resources to work with certain type of project, the ability to earn money with it is secondary if the project brings to the doer pleasure and joy. Not every endeavor is about making money. Sometimes it is just about how to spend it.

 

I believe that the only way progress is going to be made is to think -to use the old cliche-"outside the box". Progress in high power trimaran design has been woefully inadequte for boats 18' and under. New thinking and new technology applied in new ways can change that.
As proven in very detailed comparisons in the F 18 thread a "beach trimaran" can offer , more power, more comfort and an easier to sail high speed boat than can a cat. Applying some of the things learned in researching that thread-carefully- to the 10-14' boats in this thread is an interesting challenge given that -like in the 18 footer- there is nothing, absolutely nothing available now that uses the full range of state of the art modern technology on a trimaran design in this size range. I will propose some solutions that take full advantage of this technology as I did in the F 18 thread....
The basic theme of the 18' tri is summed up like this:
More Comfort- More Speed- Wide crew range(singlehanded or doublehanded with MAX power)
I want to see if that theme can be applied to boats within the range specified in this thread-and to what extent it may or may not be possible.

This is certainly worth reading for anyone not familiar with it:

While this is about catamarans from an interveiw with Martin Fischer, I think it applies to ALL multihulls-most particularly a trimaran that could accomplish the challenge of this thread:

CS - Is possible to see in the future a stablished racing class of foiling beachcats ?
MF: Yes, I am absolutely convinced that foiling multihulls are the next step. The challenge is to make them reliable and easy to handle. I am currently working on putting an A-Class on foils. First tests are very promising. I start flying the boat, also it is not very stable yet, but I think we will get there.

CS- I've heard from Landy in the A-Class, from M20 pics and reports and from Macca in the Nacra F20 how they are flying with curved boards, so slowly we are going in that direction, not full hydrofoils of course, but is the future in your view (flying beachcats Moth style)?
MF: Yes, I have here in New Caledonia an A-Class with curved foils. The boat works nicely but it is not yet fully air-borne. If everything works according to plans I’ll have a flying A-Cat before the end of the year.

The full interview is here: http://catsailingnews.blogspot.com/2010/05/cs-interview-martin-fischer.html
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6/29/10 PS- take a look at at the paragraph I added to the first post of this thread......

 

A look at whats out there now

Here are two small tri's that are great small boats:
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12 footer by Kurt hughes- http://www.multihulldesigns.com/designs_stock/daysail/12_tri.htm

LOA 12'
Beam 10'
Upwind SA 68 sq.ft.
Weight 160lb (crew for calc below 175lb)
L/B main hull= 5.14/1
L/B ama = 11/1
SA/D= 22.5/1
W/SA= 4.92
SA/WS=1.9/1
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Marples 3m (10') tri http://www.duckflatwoodenboats.com/mainpages/gallery?KID=52
Beam 8'
SA 64sq.ft
weight 150lb
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One thing immediately noticeable is that the main hull of both boats is a displacement hull with a quite low L/B-5/1-in the first one. So that limits the speed potential right off the bat and explains the small SA. Why have more SA even though there is ample stability when the power couldn't be used. It's a good solution for two fun sailboats.
But I'm looking at another idea-much more power by flying the main hull, increasing SA and by using relatively small amas. These boats probably would not be able to generate enough speed to fly the mainhull using either foils or a planing ama-just wouldn't work. The only way that I can see is by having a much larger ama that would then suffer from the same problem as the main hull-too low an L/B ratio and/or too much wetted surface.
When I say "problem" I am not saying there is a problem with either of these boats-they are great,fun boats! The "problem" is only theoretical when considering modifying either to fly the main hull. And the solution is simple: don't do it.
But I can assure you that doesn't mean a 10 footer couldn't be designed specifically to be fast enough to fly the main hull and offer more room and more speed-at least theoretically. More to come.....


To understand the Design Ratio's used above and to find the numbers compared with other boats check out Eric Sponberg's
PDF below: (does not include W/SA=all up sailing weight in pounds divided by sail area in sq.feet-mostly a foiler or low resistance boat quick and dirty comparative ratio. Literally "sail loading": how many pounds does each sq.ft. of SA have to move?)
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Check this thread for the really cool Maora 10 foot tri: http://www.boatdesign.net/forums/multihulls/maora-10-cool-little-tri-33528.html#post379050

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Marples 3M under sail, Hughes 12 footer sail plan-pix from sites above:

 

So the concept includes a 19 foot mast on a boat that has a 7 foot waterline length when on a single hull and that same 7 feet is also supporting 160 kgs? Have you considered pitching issues (let me guess - hydrofoils!)? What about the hull shape needed to get the volume into the float? A Weta rigged weighs around 100kg apparently. How have you arrived at the figure of 55kg for a boat 75% of the length? Have you addressed these issues?

What happened to the last project(s)? How is that you have so many increadible breakthrough treasure chest ideas on this forum and yet so few make it through to anything that actually sails? (maybe!)

 

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1) Weight varies as the cube of length so if you wanted to compare the 220lb 14' WETA to the MPX-11: 14cubed=2744; 11 cubed=1331. So 1331 divided by 2744=.485 and .485 times 220 gives 106.7 . So the MPX-11 is actually 13.3 lb heavier than a scaled down WETA!!!

2) The ama on the 11 footer may be (updated 7/3/10) proportionately smaller than the WETA ama and utilizes a planing hull whose center of lift is a bit forward of the forward cross arm. In addition, the main hull of the little boat uses(you guessed it) a hydrofoil on the daggerboard and one on the rudder. This allows(in combination with a wand/manual altitude control system) the possibility of setting the angle that the boat flies when it flies the main hull. The wand also allows the main foil to make up for missing weight when a lighter crew is on board(retaining the same max RM even with the lighter crew)-and it does all this automatically. Further, the two foils work together to control pitch which allows the ama stepped planing hull to operate at the most efficient angle of attack.
3) A major difference between this boat and any other trimaran, that I know of, is that both hulls are planing hulls-that seems to be the best way to achieve the required volume. Because this is such a small boat and the planing thresholds of both the main hull and ama are so low it is possible to sail the boat with the ama out of the water until the boat is moving fast enough for the ama to plane.
4) the ama waterline can vary-nominally it is about 4'-not 7'(depending on speed-planing "section" is 6' LOA-ama is 9' LOA-updated 7/3/10) and at a certain speed can support the weight of the boat. Thats a major key to this idea. It's also an area that will require a great deal of experimentation. But the theory is solid.
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What was the last project? There is only one--more or less- project that I am involved in currently. This stuff is exploration and hardly deserves being called a "project"- though you never can tell......

 

Re: your projects. From memory I thought you were developing a super-foiler (X-21 - the one with the converted cat hull?), the trap-foiler (the one with the moving ballast), and now the trimaran foiler (though this isn't a project you say). Whatever - I guess I just feel like you make grandiose statements over the potential of each of these ideas but never actually test them in practice. I think completing a project would equip you with a few reality checks that could be helpful for subsequent designs. I say that in an effort to help progress your designs.

Anyway - the maora is an interesting little boat. Even "underpowered" as you say, it doesn't look capable of holding much more sail. The mast looks pretty light and is heading off the leeward. The floats look small and probably < 100% displacement. The weights quoted sum to 115 lbs which is over your target and not likely to get much lighter when you beef everything up to handle more power. Re your previos point on scaling mass by the cube of length - I know where this rule comes from but I don't think it is quite as accurate at this scale. The cube of length gives a volumetric figure. Your smaller design still needs to have the displacement to support the crew weight (which doesn't change with length if comparing boats with the same number of crew) and I therefore the volume remains broadly the same. As a result, I think it difficult to see how you can expect to nearly halve the weight of a Weta to arrive at your nominated mass. After all - the maora above weighs approximately the same as your target mass and is smaller and carries only a fraction of the sail area you propose. In short - I think it will be very difficult to achieve the parameters in your post.

 

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1) You may not have caught everything in the Design Challenge thread-your comment makes it obvious that you didn't. The Trapwing is my number one priority but not the only thing I am working on or interested in. I don't make "grandiose" statements(in my opinion)-everything I say I back up with detail. I think that design threads such as this are interesting and as I learn more I post it to share with everyone. This thread has followed the development of the idea to some basic(though well researched) numbers and I will add more as time goes by. My point is to prove that it is possible(or impossible) as the case may be. If it turns out to be as good as I think it is it may get built-or not.
If you look at my gallery you can find numerous projects that have been completed over the last 30 years.

2) The Maora appears to me to be a rotomolded boat-and very well designed for a little beach toy-the MPX-11- would use light weight material and, I believe it would make the weight target. However, there is substantial leeway considering the max crew weight*. It is in another category completely from the Maora.

3) My figures comparing the scaled down Weta and the MPX-11 are correct as best I can tell.

* also note that I specifically referred to the numbers for the MPX-11 as targets-and given the design ratios that have resulted there is quite a lot of leeway when it comes to weight-and sail area. Cost has not been considered as yet-only performance-I believe that is a chance that can be taken at this size because it is basically a very small boat with a rig not much bigger than a big windsurfer rig. More analysis will come as more research is done...

 

It isn't worth continuing the debate on you relevant experience. We probably both agree that it speaks for itself.

Rotomoulding is indeed not a lightweight material. It is probably a key factor in how they keep the price down though so it comes down to that "Here are three properties (say; cost, light weight, reliability) - pick any two". The non-project trimaran will probably have to play by the same rules. I think the point about volume being a determinant of mass is valid. After all, density of construction materials x volume = mass. I guess a proper design and calculation would resolve this one.

Anyway - I won't intrude on your wandering of deserted beaches looking for treasure for too long but I will leave you with one thing to think about.

In the perfect world where the trimaran is sailing along with the foils supporting the main hull and the leeward float skimming the surface what angle do you expect the craft to be tilted to leeward? At this angle, which foils will resist leeway?

 

The non-project trimaran will definitely have to play by the same rules, but that appears to be obscured in the mist for these types of exercises. This same phrase was applied in the last thread regarding a beach cat killer tri and it was ignored there, as well.

Such as it is.

Ahhh, yes, Which foils will resist leeway? That's a good question that reaches further into the whole design process, especially from a pragmatic, commercially produced perspective. Heck, it even applies to the one-off guy who is now being obligated to knock-out a whole collection of various foils, all with different sections and strength requirements. More foils, equals more time, equals more cost, equals folks heading for the exits... and that applies whether the boat is self-made, or commercially produced.

Can it be designed and built? Well, sure. Just about anything can be drawn-out and then built. Another, even bigger, question looms just beyond that recognition, though and nicely enough, it is never asked on any of these threads because it goes right to the heart of the matter.

Folks can dream about wild stuff as much as they want. I even encourage the process. If this were an art project that only needs to exist to be a fulfillment, then dandy. If one is going to be comprehensive in their design approach, though, then a whole car load of uncomfortable issues come along for the ride. To ignore them and dwell in the single-sided, "gosh, isn't this a cool, ever-so-detail-oriented idea?" mode, demonstrates a less than honest approach to the process.

If one doesn't like the functionally pragmatic aspects of the argument that are being dismissed off-handedly by those who wish to brand the aspects as negative thinking, then by all means, attach your ideas to a zippy cool lawn chair and go floating off under a wild collection of helium balloons. Eventually, you'll have to come back to earth and the questions will still be there.

Well, Munter, you tried....

 

If you were around this forum long enough you would be able to add the 12 foot "monofoiler", the 14 foot "monofoiler", the 17 foot "monofoiler", the 17 foot canting keeler, the 20+ foot foiling sportboat, the 60 foot "monofoiler", the KFoilers, etc, etc, etc.

Of course not one of these concepts had ever had a proper drawing of any sort presented, save the one that he had drawn by someone else. Certainly none of them have ever seen the build part of the equation (although it has been claimed that he was "building" a number of them at one time or another).

 

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First of all you don't know what you're talking about-I've presented many ideas that were translated into detailed preliminary calculations that MUST be done before any drawing except preliminary sketches. Not every idea will turn into a viable project but I have many interests based on a long history of designing, prototyping, testing and building boats from models to full size. I don't just spout BS like you do- I back up my ideas with concrete numbers. Numbers that are CRITICAL as a first step in trying to understand if a new boat is viable or not. I have presented unique concepts backed up by detailed calculations that you have never ,ever been able to refute. I don't ever present finished drawings because I don't believe they come close to telling the story that detailed numbers do-especially in terms of the new design ideas that I present. I'll show detailed calculations and models where it may help-drawings of the concepts I present(other than preliminary sketches) wouldn't give a tenth the information I present with numbers. The plans I draw are working plans-done to get a prototype going-not to present publically-I don't sell plans-I sell and develop ideas. You simply don't understand the process I've used for over 40 years and that has resulted in numerous boats on the water( and a few patents).
But how could you know-you have never designed or built a single boat according to your own words: (post 38, Little America's Cup thread)