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John's piece on outriggers in the November '99 issue of Gossip raises the issue of how the length of outriggers might affect the speed of the resulting multihull.

Philip Bogler quotes the late Arthur Piver in his book 'Boats with and Open Mind' - "a trimaran's floats should be as long as the main hull since they would (then) move at the same speed".  As he points out, some people who should have known better were imitating the wing-tip floats of flying boats - a very different application of outriggers.  From my own very limited knowledge of the Indonesian trimarans their pole outriggers appear to be generally at least as long as the hull, and sometimes longer!  This suggests that a faster, less unwieldy answer might be the catamaran where both hulls are naturally the same length.  But would we then be moving out of the realm of the sailing canoe?

I think if the outriggers of a canoe trimaran are arranged so they are both normally out of the water, and the leeward one comes into action on it to prevent a capsize, maybe length would be of less importance;  rather like the use of floats on a flying boat.  However, in such a case the sudden resultant drag from the immersion of a short outrigger might present a problem in itself.  To some extent though these problems may be more perceived than practical, especially if there is not too much disparity in the lengths of the main hull and outriggers.

Remember it is waterline lengths which matter.  In the case of my own 3-metre trimaran the amas (outriggers) are compounded from 8'0" long sheets of ply so are something over 2'0" shorter on the waterline than the main hull, but when a gust accelerates the boat and the leeward ama is more deeply immersed there does not appear to be any greater drag on the steering.  This suggests that the immersed ama is not unduly slowing the boat.  A ratio of 1:4 - outrigger to hull - may, of course, have a greater effect.

In the end it really comes down to the type of work the outriggers are intended to do, ie. add to speed potential, prevent a capsize, or both.