So I went out on a kneeboard a few days ago for a few reasons (working through a few injuries, out of shape, waves were fully cracking) and found that the Friar Tuck I was riding slid out on steeper, hollower waves. The bottom contours are quite tame and it has a nice hard edge in the back. But the 5'5" length is combined with 23.5" of width and the thickness is carried pretty much to the rails.
I have a Romanosky kneeboard of the same length and it is narrower, maybe 22" wide, and has its fin set placed further back and definitely works better in steeper, hollower, faster waves. But it even feels somewhat bloated.
With that said, it doesn't seem that a kneeboard needs to be much more than 20" or 21" wide considering the method of riding and the kind of waves a kneeboard should really be performing in; why would anyone take a kneeboard out in soft, slow waves?
So, why so wide? Historical reasons? Chicks dig it wide?