This thread has gone completely to the technical or should I say mathematical side of the equation, instead of the basic question of should he build it or not. I say build it. As to the earlier statement that A's are out because of their 7'6" BEAM. That is not applicable here, for you would be using other beams. I know of a few sets of A class hulls that could be had for this project. All of them need some work, but that is about it. I also possess two T-Hulls that could be had for the right price.

What I like about tri's beyond their inherent stability is the fact that they point higher than most cats do. I built my trimaran "Skyhook V" with my partner Ken King, formerly of Navtec and launched 1994. 39’10”LOL and 28’4” on the beam. Built of western red cedar with e-glass skins and carbon fiber at the main stress points. The design was one that we began and Chris White finalized. This is a 20 design of his to look at for ideas. http://www.chriswhitedesigns.com/discovery20/index.php
http://www.2hulls.com/usedtrimaran-2001/skyhook.html
Fast boat, but built more for cruising than racing, without some of the penalties of these heavier bathtub cruising cat properties.

Build it and goes have some fun.

The direct reason for using science and mathematics in projects like this is to establish what can be expected. It is the whole reason why 80 % of science was developped in the first place. Without it we'll be back at our gut feelings and 5 senses, both of which are easily tricked into believing things that are simply not true.

From point of view if you want to spend a considerable amount of many developping something then you better know before hand whether it is a reasonable change of succes. If the underlying principle has a fundamental problem preventing you from achieving succes then going ahead with the problem will be very risky financially speaking. Miracles do happen but sadly alot less often then people think or hope.

The original poster did ask about performance expectations and I think the math did give him a better idea of what can be achieved.






How can the tri by more stable then a cat of the same dimensions considering their righting moments. In fact a tri build for waters with waves can not have all three hulls in the water at the same time. That would negate most of the "advantages" of the tri design and make it take alot more punishment from the waves. Ift one hull is lifted out (the luff hulls) and this happens at relatively light winds already (where stability considerations are meaningless) then the stability of the tri is determined ONLY by the distance between its leeward ama and the centre hull. If this distance is less then halve the width of the catamaran then the tri will have LESS righting moment then the tri and therefor have LESS sideways stability.

The fact that a given tri can point higher can only be explained by its slower speed.

Again the math discussed earlier in this thread explains all this. It wasn't math for the sake of math, it dircetly answered some of the questions asked.

So basically I expect the 16 foot wide trimaran made out of a 6.0 or tornado hull and two A-cat hulls to perform worse then the a 6.0 or tornado catamaran and even worse then any 8 foot wide catamaran with comparable sailarea. With the possible exception of very light winds where the tri can be balanced by the crew on the centre hull only.

Wouter

thanks again to all who have contributed here... i'm learing a lot about cats in general that i've not known....but back to my original post... there's no a-cat hulls in this project.. no 6.0 hulls. I own an 18sq, and own a tornado mold.. so if this project happens it will be with those hulls.

I'm also coming across two distict types of tris here. A pod style where the center hull is smaller than the amas and is designed to fly both hulls, and a larger center hull/smaller amas that is designed to stay in the water. it seems to me that on the later design, the center hull carries the weight of the movable balast, (me), and the amas carries the load of the sail. this seems to more along the lines of what i'm proposing. I do realize that it will be slower than a cat, but should be reasonably fast with a larger crew which is my goal. is that a fair statement?

Yes, I think so.

You'll beat any monohull out there.


Wouter

You should do this to the tri:

http://www.sailingscuttlebutt.com/media/06/0814/

Doug

I want one, the smaller version looks like a blast.