Sorry, Les, it's a theory. If you don't accept the evidence as presented, that's your choice. In either case the data, such as they are, should be testable. Now, if you want something untestable, tell me how many angels can dance on the head of a pin.

Paul, as someone pointed out earlier, canoes also are ribbed vessels, dependent upon ribs for their shape. Rather than making the issue one of mass [which is really an inertia issue] you should be looking at fluid resistance. It is possible to greatly increase mass while only minimally increasing resistance. Part of the reason for increasing the number of sails in the 19th century was that ship owners needed to make sails more handleable by the reduced crews they were willing to pay.