18' Trimaran vs F18 Catamaran

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I infer nothing of the sort. I point out several times the performance enhancements I would make-and that would be necessary to make for the tri to be faster.They are mostly design changes which I describe in detail. And even with those improvements included cost is the same.
You are dead wrong and can't admit it! Funny.....

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Point is that both boats are built with similar material and with a few low-cost design changes the tri could ,without a doubt, be competitive with an F 18-probably beating it in most conditions-NOT THE MAGNUM but a tri built using the same materials with design changes that enhance performamce-the biggest being that the "peformance" tri would fly the main hull. Cost will be in the same ballpark as an F18 Wildcat......

 

How much do you think it costs to hire Fischer to design a proper and much faster hull, foils, etc. for this remarkable machine you say can be produced for the same amount? This boat has more hulls, more tooling required to produce those hulls and more shop space to store and produce the boat in question. Do you think all that stuff is free?

All of those costs, along with all the needed upgrades for an equivalent trimaran, have to be included in the price of the boat, or whatever company that risks building this, will soon be out of business. I know that in your world of balsa gizmos and art paper sails with crinkled blue drop cloths as photo backgrounds, you tell yourself it can be done and everything is going to be free, cause you won't charge yourself... but it just doesn't work like that for anybody outside of your little zone there.

This has become a boring, tedious discussion. One that you should enjoy with your fans.

 

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What discussion? You said "Prove it". I did. Just admit that you were dead,flat wrong! You'll feel much better......

 

If toyota can get a chinese mainlander to work in a car factory for usd180/per month then there is plenty of margin to get cheaper boats!

 

F18 vs 18' tri

It's not a question, so much, of needing cheap labor to do a tri at the same cost as a top end cat. The design of the tri is critical. For instance, on the Magnum, the total buoyancy of the ama is 100% of the weight of the boat WITHOUT CREW! That means the boat will not fly a hull. According to the company it also means the costs can be lower. The small ama is less than half the "skin area" of an F18 hull which addresses a major myth of those that say you can't build three hulls as inexpensively as two.
This is what the company says about the Magnum 18:

Can the Magnum 18 be sailed on one hull?
No. The volume of the leeward float, 200 litres, displaces the same weight of water as the whole boat when fully immersed, 200kg. This means that it will sink before the main hull will lift off the water. This gives the skipper the clue that either he or his crew need to sit further to windward or the sheets should be released or the sail reduced if it is happening a bit often. Thus it acts a bit like a safety valve or fuse. If the amas were made big enough to support the whole weight of the boat then the akas (cross beams) and their fixings would have to be made stronger and this would add weight to the boat.

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The fact is that whether a tri flys the main hull or not is a design choice and the tri that is the subject of this thread would be about the same size as the Magnum ama but it would have one huge difference: it would be designed to
use dynamic lift to fly the main hull using one or more of the methods discussed earlier. Flying the main hull is the major key to beating an F18 for an 18' tri. Doing so with a small ama and dynamic lift is one of the keys to keeping costs in check.

 

And cheaper hardware and cheaper sails, spars, tramp material, etc. It doesn't remove the fact that there is still going to be more tooling, design work, engineering, additional parts (foils and trunks, to name but a couple) and added shipping costs due to fewer boats fitting into the same container, and on and on the list grows.

Like I said with tongue in cheek... one can probably get them built very cheaply in Rwanda by the Tutsis, with a gang of Hutus standing nearby with machetes, but that doesn't make them comparable, or even satisfactory.

Maybe you've seen the quality of finish on Hobie Wildcat in person?.. Or the Capricorn, which was the original example shown at the start of the thread? Both of those boats have gone through very stringent engineering and design study, prior to being introduced. The work was performed by the top guys in the field. That work doesn't come for free and it has to be amortized during the early part of the production run in order for the profit numbers for the boat to be recouped by the investor. To produce a comparable trimaran design will also require a similar, if not better, design program which will have to be added to the cost of the boat. That figure is not being shown in the so-called analysis being shown.

The necessity for curved foils, their specific trunks and control systems are also not being shown in the weight, or cost analysis. There are two of them for each boat and they are not simply glued in place and called good. They have to be engineered specifically to match the requirements of the boat. They also require seriously reworked ama-to-aka juncture points, stronger aka beams and a whole host of other improvements that must be properly engineered, or the boat will break regularly when being used. The standard, sliding tube aka setup of the Magnum will never be able to handle that kind of load.

Changing the convenient consumer oriented sliding tube system will also require a reworking of the aka-to vaka hull mounting locations to provide enough strength.

The rig will have to be quite a bit bigger, in order to get the tri to a comparable power to weight ratio. One can sidestep, partially, the addition of a heavier mast by going to carbon, but that will also drive the final price upwards. The bigger rig and its attendant compression forces will necessitate a stronger mast step and the load bearing bulkhead beneath it will also need to be reworked by the engineering team.

I'll stop here, but I think it's more than obvious that the Magnum example is so completely irrelevant that it's kinda comical that it was brought forth as a credible, weight/cost example in the first place. This magical boat will not meet the weight of a Capricorn without the use of exotic materials, such as carbon. That will drive the price upwards. It will not meet the needed power requirements without a significant change in the rig and all the rest of the connected inventory to service the rig, e.g., hardware, mast, boom, sheeting system, the whole works that should be on a boat that is being claimed as a beach cat killer.

The supposed boat will need to be as good looking, or better. This means styling/design costs up front, before any tools are built for production. It will have to be kitted-out with as good, or better, of everything one see on the Carpicorn to be considered in the same game. This is also added weight over the already over the line existing weight of the Magnum. It will need substantially fresh engineering, with costs to be borne up-front, to allow for all the "enhancements" needed to maybe get it into the game. It will need the use of exotic materials at higher production and retail prices in order to try to get the weight down to something like a competitive relationship to the Capricorn and its known abilities. This trimaran will need some kind of trick and very expensive marketing plan to get sailors to switch over from a boat which is much easier to rig, trailer and sail... and is already on the market with huge market penetration already in place.

So, you see, this isn't a simple, “I'll sketch this thing on a napkin” exercise, if one really wants to produce an equal length trimaran that is a beach cat killer. It was asked way back at the front of this thread, why hasn't anyone done this already? I think that the answer is obvious and in a general fashion, I've laid that answer out before you. Specifics will only drive home the reality more conclusively. You can argue until you’re blue in the face, but you can't change the facts. You want to equal the speed of the Capricorn, you need to get out the check book and be ready to throw quite a bit more money at the boat that "might" be able to do that. In the meantime, you're missing out on a lot of really cool sailing days while the existing boats are sitting on the beach, waiting for sailors.

This idea is DOA until something enormous changes in the way that small craft are built and marketed.

So, that's it with the Magnum as the answer, Doug. It's not even close to an answer and no amount of jockeying around with the numbers and ignoring certain spendy and weight adding aspects is going to change that fact. You've pulled a dead fish argument out of your pocket and tried to foist that on the nice folks who read these pages, as a substantive argument. It would be good if you stopped assuming that the members are fools and will bite on the next wild idea that comes out of your thought process.

It might be fun to imagine a boat that was as affordable as the Capricorn with more power and more comfort, but in this case, the path to getting there means that one of those things will have to be delisted in order for the boat to make any sense at all.

Affordable, power, comfort.... pick two.

 

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1) There are a number of options for foils: DSS retractable foils are probably the best solution since there is nor no requirement whatsoever in my proposed solution for lateral resistance to be generated by ama foils. In fact development may prove that the rotating hull is the best solution
requiring no foils whatsoever.


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2) the Magnum was not presented "as the answer"-far from it. It was merely an illustration that an 18 foot tri could be built and sold in the ballpark of
what an F18 is. I carefully and thoroughly explained earlier just what the Magnum illustrates. Since the Magnum is several thousand dollars less expensive than an F18 it is reasonable to say that a high performance 18' tri could be produced and sold at a cost comparable to an F18.




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Doug,

The use of a boat that, by itself, is unsuitable for a proper comparison (the otherwise nicely targeted recreational oriented Magnum 18) is not a comparison at all. It's a fallacy.

If you really think that you have some magic elixir for this made-up issue, then do this: Go pay for a qualified designer to draw-up a boat that will do all that you think is necessary to get to the place you stipulate, take the drawings to a professional boat builder, or twenty, and get them to offer bids as to how much the designed boat will cost to build and fit-out properly as a completed craft. Add the cost of marketing, transporting, etc., along with the all-important profit margin needed to pay overhead and the ongoing costs associated with the get-ready phase for production. (e.g., tooling, storage of same, administrative costs to negotiate on going problems, etc) That is going to get you to something like an understanding as to how much a specific boat will actually cost to the consumer.

When you get that number, you let us all know by showing the complete paper trail that was used to get there, as well as the design of the craft, in detail, so that all of us can see just exactly how the solution was achieved.

Until you do that, you're whistling in the wind and nothing more. Since nobody has actually built this type of boat before, your numbers, even then, will be highly suspect until a boat is on the water and you can show that the business plan is viable through continued sales and the process of keeping the doors open.

Like I said, DOA. The rest of this is more hooka puffing. As a hooka exercise it's just dandy, but just as the cloud eventually clears from a late night smoke-out, so will this exercise and there'll be nothing to show for it.

 

Im not exactly sure why the question is being put forward in the first place considering the proposed tri has almost twice the beam and same displacement as the F18? you would have to screw up pretty badly for it not to be faster

 

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The question is "put forward" because the tri develops its F18 killer speed with the crew sitting comfortably near the center of the boat-no trapezes,no running back and forth. In addition the tri can be sailed in the same conditions as an F18 single handed or doublehanded...
More power, more speed, much more comfort, much easier to sail fast.....

 

I'm only interested if it has a powered sliding ballast system and bench seats. Without those the design doesn't realise it's full potential.

*Edited for clarity.

 

Pitchpoling

Danger with small (short) amas is the tendency for the craft to go to pitchpole. The Weta (4.5m) has relatively largish long amas and it still pitch poles. In a boat that size that is OK as she rights pretty easily (I know from experience) but in an 18 footer? Not sure that would be alot of fun.

Still I guess beach cats will do that as well so it suits the comparison.

As for the rest of it - Chris' commercial comments are spot on. Doug, you keep saying things like "the performance improvements I would design" but mostly it seems to be just words and a heap of numbers. Show us some 3D renderings or one of your famous models so we can see what performance enhancements you mean. Do you have a background of the design of high performance tris that sail fast?

Cheers,
Andrew

 

Doug, going into production with a complex foiling trimaran sounds like a hell parade - Chris obviously knows heaps about the process and it sounds again like purgatory to me. And I like the idea of a minimalist tri taking on the F18 cats - but no thanks. Chris is right, to compete you're going to have to go to near all carbon ... and that's the end of the dream because of cost ... unless you can use very reasonably priced carbon tows like Rob Denney does constructing his proas and their masts in the Kelsall manner. An 18 foot version of Scissoring Sid would maybe be competitive but look at the structure: main hull, wide single airfoil beam, smart main beam bearing, floats and foils and cases, then attachments, then rig - it is just too much boat to build compared to what a simple thing a catamaran is.

 

So you won't be buying shares in Doug Lord Beach Tris Inc then Gary?

 

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Andrew, it might actually help to read this stuff-as it seems that you may not have. This proposed design uses lifting foils on the daggerboard and rudder of the main hull and would therefore have tremendous pitch resistance as compared to an F18 or a trimaran sailing only on the small ama(like a Magnum 18). And if it worked, might be able to use a ROH hull.....
"Just words" and a heap of numbers?! Well, yeah, you're right....... You should really make an effort to understand those words and numbers. In fact, without understanding them there is no way you can intelligently comment on Chris's commercial comments as they may or may not apply to this design or the viability of the design. So ,please do try.....
-I've designed and built two small tri's that were very fast-a 14 footer and a 20 footer-both with planing main hulls. I've designed and built as well as doing the tooling for two production RC tris and experimentally built and tested many more as well as numerous other state of the art RC models. Production boats based on my design have sold over 300 boats.