Hi, I have a 1971 17' Mastercraft Trihull. Before I start drilling holes in this boat I would buy a selfbailing boat. It was just a crazy thought. Tomorrow I plan on fishing in Little Washington NC. It's brackesh water and I am not sure whats running now. Washington is a bout 1 hr from my home in Wilson.NC AlThis is a great group!
Self bailing boats were an adaptation of the idea that trawler designers/builders used to bail the decks through holes ABOVE the waterline. These water outlets have a nautical name although it eludes me now. These holes can be seen from a distance on most trawlers from the easily recognized stains left from water and stuff flowing overboard. Modern rafts and now pleasure boats have the bailing holes usually at or above the waterline. Just like the trawler, they only work as a function of major positive bouyancy. Any significant loss of bouyancy and you know what happens. My guess is that these holes work due to the tremendous amounts of added bouyant foam injected into hulls these days with assistance of check vavles (water valve that allow water to flow only in one direction). My guess is that buying a self bailer is indeed the right choice. Your 71 Mastercraft would probably sink like a rock if she had holes in her and besides, you would never sleep a wink if you removed her bilge pump and that sage advice comes from experiencing several sleepless nights when my pump was out. Don't catch em all! Good luck and go get em!
I have resently bought a 16CC that is self bailing. Under the deck is the fuel tank and a small builge area at the stern the rest is foam filled for flotation. Even with the self bailing deck the manufacture has installed a builge pump, I wouldn't have it any other way! If your boat is of the right design you could modify it to a self bailer by adding a deck above the full load waterline. Then adding floatation and sealing the deck but you will lose some of your load capacity and could cause your boat to be top heavy and therefore more subseptable to capsizing. Foregive the spelling, not my best subject.
I have worked on boats for a long time and never seen on that could be converted to self bail. You still need the pump for water that will collect in the billige. Self Bailing boats will revmove most of the water from wave breaking over the side or sea water wash down things like that. You will still get water in the billige and need to keep that pumped off. I have a self bail boat and have a 1500 GPH pump on a automatic switch with 11/2 outflow line.
Self bail boats have been around for many years. You can find a hull only and use the parts off you mastercraft to repower and make yourself a nice self bail boat. Here is on web site that has some of these boats http://www.budgetboats.net/boats.htm
Hope this helps you