u/iddereddi

Bottom of the hull got 2 layers of 200g cloth and inside got 546 liters of EPS100 foam, weighing 9,92kg (I weighed the EPS before and I weight the leftovers and calculated the volume). The old outrigger was only partially filled with foam (~20% of volume) and expanding-contracting (summer-winter / sunshine-clouds) kept breaking the fiberglass seams, as the sides were bending back and forth. Gaps between the EPS and plywood hull will be filled with 2 component PU foam also increasing the rigidity of the hull.

I do not store my boat in water, so the PU soaking up water is not an issue and the EPS is foundation rated, so no water absorption from the EPS.