NavList:

I guess the question is one of claims of purity versus deeds.   If they're claiming it's pure, yes, it's certainly lacking.

I had a tangential question that perhaps someone can answer here.   In terms of the crab claw sail - I've been comparing the crab claw design to the lateen design.   The historical references I've seen claim that the crab claw and lateen were of independent origin.  

In thinking about the utility of the crab claw, it struck me that having more square footage higher up might be advantageous for the following reason:   if you have a viscous drag of air over the surface of the water, the air near the surface is of a lower velocity than higher up - therefore a crab claw design would maximize the wind velocity the sail can utilize, while retaining an airfoil design.    I haven't calculated the gradient of velocity above the surface of the water, and it probably depends on the sea-state.   Does anyone have any insight into the utility of the crab-claw versus lateen?

John H.