I use a number of criteria. Mast and beam bury, hull stiffness, bow freeboard, max prismatic, min wetted and overall surface. Very difficult to make a <100% hull with these criteria, and even if you could, I wouldn't, certainly not on an offshore boat where waves become a problem for low buoyancy hulls.
rob-
what is your design criterion for volume of the lw hull? i assume it is substantially more than 100% displacement of the whole boat.
i ask because i wonder whether it might be beneficial to have it <=100%, so that one could never fly the ww hull. impossible to flip sideways then, and a good indicator of when you're pushing it too hard.
weta floats work like this. <100% and wave piercing. surprising how difficult it is to flip them, though it does happen.
ben> BD's lee hull is huge compared to any trimaran lee hull, and plenty big
> enough for the immersions it sees.