97 February 1999. Proas in which the outrigger is always carried to windward.
Trimarans use the buoyancy of the leeward outrigger.
The windward outrigger does nothing except cause unnecessary windage while it waits to become the useful leeward outrigger when the boat tacks. Canoes with one outrigger which is always carried on the same side use its weight on one tack and its buoyancy on the other tack. Traditional canoes always had solid outriggers and fortunately many light woods have about half the density of water so that their buoyancy is about the same as their weight and the canoe should have similar stability on either tack. Many modern canoeists use a single hollow outrigger something which, so far as I know, was not done traditionally. I think it probably only works well when the canoe has almost enough stability without the outrigger, which I suppose means most modern canoes as opposed to traditional outrigger canoes which were usually so narrow that they would not float the right way up without the outrigger.