Builders' Forum Archives
Re: hatch vs drain hole
Posted by Howard on Mar 26, 2005
any anticipated watertight compartment in a boat hull should consider three issues. 1) air pressure equalization 2)the need to be able to remove moisture/water that gets into that space and 3)an ability to inspect/reach the interior structure of the space to verify its condition or effect a repair.
air pressure equalization is important as the air in the space expands and contracts with the heat. if there is no way to equalize the pressure, the hull can be deformed, particularly when the air is cooled. it is best handled by drilling a 1/8 inch hole in the centre of each bulk head.
for getting moisture out, the most minimal approach is a drain plug which can be installed in the bulkhead along the keel line or on the deck just in front of the endpour. the drain plug needs to be in a corner that is easy to get the water to drain from in order to be effective. drill the appropriate size holes and before installing the drain plug, wet out the exposed wood with epoxy to seal it. then when sealed, install the plug with a some silicone sealant to create a gasket. the downside of the plug is that if you put it in the bulkhead, it can be hard to reach. it also is not very effective in allowing you to really air-out the compartment....which is something you want to do when you store the boat for any length of time.
for inspecting the inside of the structure, drain holes fall short. an alternate approach for those who don't want a hatch...but want to ensure that the hull gets aired and to be able to see what is going on inside the space...is a beckson hatch...6" in diameter. this is the approach i use when going hatchless. the nice thing about this approach, as just mentioned, is that you can really air out the hull and also get a look into the space.
of course, you can always go with the hatch...it has the added advantage of giving you storage and it is very easy to inspect the inside of the hull without performing gymnastics.
as for the flush hatch...when installed properly, they are just as waterproof and tight as the other set-up. so its really a matter of personal preference. i think the reason you don't see that many pictures of that arrangement is simply becuase it is an additional cost option that is not actively marketed in the chesapeakes.....so most people are just building and taking pictures of the standard design.
In Response to: hatch vs drain hole by Vic F on Mar 26, 2005