Hammers? Kevlar is used to stop bullets right - once Necky, P&H or somebody does the Machine Gun Test on a Kevlar kayak and posts it to YouTube...then I'll take notice!

I've stood on the deck of a Chatham too, they are pretty strong/stiff and light. But their Gel Coat perhaps not quite as thick as the Brit boats I've heard - this photo gives an idea:

http://www.atlantickayaktours.com/pages/expertcenter/repairs/gel-repair/Gel-Coat-Repair-1.shtml