question on trimaran handicap

First pictures from the sea trials:

I'll be bringing back the boat to Datchet in September. See you on the water!

Pascal

That's a difficult call... Maybe the tri could be compared to a skiff, with the floats replacing the trapeze?

Originally posted by English Dave But because the rig is on the centre hull any increase in wind strength will depress the leeward float rather than lifting the centre hull. So the drag increases with the wind

This depends on the design of the tri. On a tri designed to fly the main hull, when it does so there's just one float in the water so it's pretty much like a cat. On a tri designed with a planing main hull, the crew would compensate the heeling by sitting out on the winward trampoline.

Originally posted by English Dave You also have the problem of tacking. It's hard enough to get two long straight lines to turn a circle, let alone three. On cats you keep the weight on the "inside" hull as far as possible to help the outside one (which has further to go) skim across the water. At least that's the theory I work to.

Tacking a tri is actually more similar to tacking a monohull because the centreboard is under the main hull, so the boat pivots around it. The floats are also much smaller than the main hull, so they just follow.

Rgds,
Pascal

Edited by Pascal

Well I am an engineer. But mostly I just bluff. This may be one of those occasions.

Doesn't it depend  on how the plane of the hulls is arranged? Most tris have their floats slightly higher than the centre hull so that only one is in the water at one time. But because the rig is on the centre hull any increase in wind strength will depress the leeward float rather than lifting the centre hull. So the drag increases with the wind

You also have the problem of tacking. It's hard enough to get two long straight lines to turn a circle, let alone three. On cats you keep the weight on the "inside" hull as far as possible to help the outside one (which has further to go) skim across the water. At least that's the theory I work to.

I sail under the auspices of the Irish Multihull Association. I have no idea what would happen if someone turned up anything other than a cat but in theory it's possible. Incidentally, how would foiling tris such a the TriWave and the Rave fit into the handicapping equation. And if lifting foils take such craft outside the remit of SCHRS then what about stabilising foils such as on F16 rudders?

Over to you Scooby!

I think you are probably right pascal - here's another comment - (and I'm not an engineer to please feel free to correct me)

the pivot point on a trimaran would be different to that of a cat and in fact would move accoridng to the forces on the boat. The pivot point on a cat is around the leeward float, but the pivot point on a trimaran would be similar to a monohull - around the main hull when upright, and then would move towards the leeward float as pressure on it increases...

this would mean that using the cat handicap would disadvantage you in lighter winds as you will essentially be sailing a monohull with a bit of extra stability...

tricky - what do others think...?