i did foam blocks to allow for drainage. poured foam is nasty when wet. it sticks to ANYTHING and sticks very well. foam will form a skin once it dries. my thought was that any water that got in there would be able to drain off. if the foam was poured without the bags, it will clog everything up.

another possible problem with poured foam and limber holes is that water can back-up into the limber holes if you forget the plug or something. you don't want the foam to get soaked. the blocks won't absorb water.

i was afraid noise would be loud and i wanted some flotation. i might skip foam if i were to ever do another.

okie's ballast/storage idea is a good one. are you putting the factory ski pole back in?