How light is it possible to build a 20 feet platform that is tough enough to endure hard sailing and tough conditions(texel, worrel etc)? Some will say that the M20 at 120kgs is already pushing the limit, and might have pushed it too far as some M20s have proven to be a bit too fragile in rough conditions.
Macca, who by the performance and sheer looks of his upgraded Taipan 5,7 obviously knows what he's doing, recently mentioned in the Super Taipan thread that he thought it was possible to push the weight of a 20 feet long,10 feet beam cat down to 105kgs. I know Wouter disagrees, but what about the rest of you?
I don't really think it is a question of it can or it can't be done. There is a transition area (grey area) where it dependents on what is considered to be "hard sailing".
I'm sure a 20 ft x 10 ft wide platform with a sloop rig can be build at 105 kg. How it holds up under varying condition is a different matter. How it will hold up in the (grulling) Worrell 1000 is yet again a seperated issue alltogether.
All I was saying in the other post is that Marstrom for some reason decided to forget about the initial 108 kg M20 and replace it with a 120 kg one instead. Remember this boat also doesn't have a jib setup which does really load up the bows !
I think Stephen has is on the right track and I want to expand on that. Reducing the overall weight of a beach catamran gets harder which each additional kg. Say you take the 140 kg Taipan5.7 (incl 5 kg spi setup). The hulls are already pretty lightweight so not much to be gained there. You want the boat to be significantly wider, this means that the use of carbon in the beams will not result in much weightsavings relative to the 5.7 as you'll need all the material you can get to restore platform stiffness. What is left ? Carbon mast ? 5 kg gains. Lets say you win 10-15 kg by using kevlar in the hulls, carbon mast, carbon beams, boom, pole and some other things. That still leaves you at 125 kg. Cuben fibre sails. Another 3 to 4 kg. Lets say you are down at 120 kg. What is now left to win those additional 15 kg of weight ? ... Not much at all. That is why some builders have decided to loose the jib as then the bows can be build lighter again. However it is still a very long way to 105 kg. Remember that Taipan 5.7 isn't an overbuild boat like the F18's.
What we are saying here is that we want to make an additional weight savings of 35 kg when a professional builder like Boyer had to work hard to win the first 40 kg. You must come up with some very smart things to do that.
It will definately be engineering challenge.
Wouter
