Butterfly Hatch

Like many people we find butterfly hatches beautiful. We also felt that it would fit the style of our boat.

Knowing they have a reputation for being leaky, weak, and high maintenance why would we chose to use one? The deciding factor was our nesting dinghy. The foredeck and mast support of the dinghy, when stowed on deck, prevented the original hatch from opening at all. We went through a lot of work to move the new hatch back and could have done the same with the old hatch but the dagger board trunk still prevented it from opening very far. With the butterfly hatch the sides open to either side of the dagger board trunk allowing for better ventilation when the dinghy is on deck. Plus, they are pretty.

Clearly we didn’t do anything about being high maintenance, but we did our best to address the strength and leaking. We didn’t take any pictures of the glass. The windows are 3/8 glass, both tempered and laminated.

We used foam core to extend the raised portion of the deck back as far as we could to make the hatch as large as possible. The forward end of the old hatch was filled with a GP03 panel.

Glassed, faired, and primed

The sides of the hatch are 1” thick. They are stepped so 1/2” extends all the way through the deck.

This detail shows several of the things we did to try to address leaking. The brass skirt provides a lip that extends down around the frame. We went with brass because the hard edge should work as a drip edge and prevent water from wrapping around the edge.

Unusual, compared with most of the traditional hatches, we installed a rubber gasket on all four edges. It is installed in a rabbit so the hatch can be dogged down wood to wood.

The hatch has not been in very long yet, but so far it is completely dry.

The hatch locks do not have a lot of material to fasten to. We had concerns that dogging the hatch down or being hit by a wave might split the small piece of teak it is fastened to. We added a couple layers of 6oz cloth to reinforce this area.

We also chose to use two locks per side in the corners, as apposed to one in the center, to help make sure the hatch stays closed tight.

Inside view (unfinished)