Sorry I never replied back. I have 3 of these boats. The one in the build I had to cuti nto the front sponsons because the screws for the turn fin were broke. I believe they were foam inside. and they are in good shape. The smaller boat .67 size they were in rough shape like you said. I know they are solid because they were stressed and the one was cracked so I broke it in half and put it back together. Will reseal and repaint them. But no worries. The third is brand new never setup or painted. so I have spare hull and new sponsons. Hope to get back at this build soon. But ya never know.