Re: Cockpit drain holes
No way I'd fiberglass the whole pipe from the cockpit to the hull. The boat flexes. The cockpit and hull move in relation to each other. That movement will stress, weaken and likely damage the hose or pipe or whatever you want to call it. That thing leaks and you could be in trouble.
Buy through-hull fittings for the hull and the cockpit. You can get them in marelon, with a plastic strainer screen for the cockpit one to keep small objects from getting lost. Given the critical need for strength, and the short run, I'd use a wire-reinforced rubber (i.e. 'hardwall') hose between the through-hulls, and double clamp each end if the barbs are long enough. What you're doing is not uncommon, from what I understand, but you can't afford a leak in that hose.