The Builder Friendly Waterproof Hatch, Episode 1.

If your looking to put large "dry" storage onto your boat this post may help you out.

This all started when I decked my last two boats. To provide access to the space created by the decking I used round plastic hatches and semi dry hatches made of plywood secured with thumb screws. The time spent on these boats has made me realize the hatches need improvement.

Working on the build plan for Enki I began to puzzle out how to build flush water tight hatches for her large storage compartments. Even though this build might be a little ways off I couldn't resist doing some drawings and making a model.

My idea behind the design was to create a gutter system using strips of 1/4" plywood. I am planning on using 1/4" plywood for the decking hopefully most of these strips come from decking scraps.

I started out by deciding where I wanted the hatch edge to be. Using a pocket saw I cut the Hatch out. This will save on plywood by using the wood removed from the opening as the finished hatch top.

The deck beam layout is important to support the finished hatch. For the model I installed the beams after cutting out the hatch. In a boat the beams would be installed before the hatch gets cut out.

After removing the hatch top I glued the gutter strips onto the deck and the lip on the hatch.

Once this all set up I dry fit the hinge and the latch.

Well this all worked so good I couldn't just waste the hatch.

Now I have a really great box and I learned some stuff. First off there should be a gasket in the gutter. For the final build I'm going to try and find a durable gasket material and add it into the design. The latch itself never needed the handle on top of the upper round so I never built it. I also see a very easy way using a spring/bungee to hold the latch closed (good if the boat is capsized in the river). I also have some ideas to reduce the amount of water that can leak in through the bolt hole in the latch (in reality I don't think its enough to worry about). Another thing to think about is structural framing under the hatch itself. If its a big hatch this will not only stiffen up the hatch but it will help keep it from warping.

Ok so there it is. Hopefully this all scales up nicely.