[bolger] longboarding plywood

this may fall into the category of Duh, but for what it's worth, a shop
tip:

i've been frustrated from time to time trying to get a nice even edge
when rounding over the ends of thin ply sheets--for hatches, thwarts,
and things--using power sanders and sanding blocks. the bearing surface
just has too many variances in hardness, and cupping results. the other
night i found a solution: longboards. they give the effect of a long
plane. very satisfying. and now that they're selling many grits of
sandpaper in long adhesive strips, you don't have to cut up a
belt-sander belt to make one that suits.