These are made from polystyrene foam 2"x 4'x 8' sheets. You can get it at building supply stores for $12 a sheet. I will be fiber glassing over them with polyester resin. View attachment 1121515
10"H x 12"W x 72"L
I got the ones from Cabela's. If they still have the ones I got they were made by Braun. I think I paid $150. each but they are good quality and fairly light.