My crew tried to puncture my hull with her trapeze hook about 3 weeks ago. Resting on the hook with her 55 kg weight and for good measure she started by slamming into the deck and then compounded by slowly sliding of the hull dragging the hook with her. Result : over about 50 mm the paint has been scrapped of the hull and over about 100 mm you can see/feel a very shallow depression (the track made by the hook). The single layer of class is fine and only the force of the scrapping is revealed by the fact that some fibres are curved in the direction of the hook moving. No loose fibres or other damage, just some small repositioning. Epoxy coating is in tact, timber (4 mm thick in that area) is fully in tact, glass layer (only on the deck between the beams on my boat and a single layer of 150 grams). damaged area and the area around it are completely in tact without any secondairy damage. No delamination (hardly possible on my boat as I hardly have an glass on my hulls), no cracked zones, no buckling, no large dent, no what ever !

Actually the damage is purely cosmetic. A touch of paint will cover the area that was scrapped bare and then only a very small depression (the 100 mm track of about 5 mm wide) will bear witness of what happened. I can live with that.

In my opinion, if this happened to a foam sandwhich hull then I would have had a punctured outer shell and a glass repair job on my hands instead of a small "touching-up" paint job.

I'm now a full believer of marine ply as an excellent catamaran hull building material !

Wouter