Wouter

earlier in this thread you quote drag due to centreboards as 21%, is this the figure an average for upwind and downwind or is it the upwind drag.

Seems to me that this drag must be mainly caused by the leeway a boat going upwind makes so that the boards are slanting through the water, I would have thought that the downwind component induced by boards must be far less than the upwind since the board is travelling parallel to it's centreline(pretty much).