Can you let me know how rigid this product is?  I want to make simple flat bench 1100mm x 400mm x 100mm for a boat.  It should be able to bear 90Kg.

This is rigid PU foam block.  rigidity is subjective and all depends on the laminate, how it is supported etc etc.  This low density block is primarily designed for pattern making rather than as a core material. The High Density PU foam block is certified as a core material for marine use.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant