http://blog.grabcad.com/2011/08/usd2000-prize-for-a-new-yacht-deck-vent-design/

This is a modification of the model number 3 (Saare Yachts Vent Model 3), but with different position of the handle to save more space. The handle is located inside the housing. This makes the vent a bit wider, but saves a lot of space inside the cabin. Same as model 3 it contains frictional plastic inlet, which can be replaced with step-acting mechanism (ratchet).
It also can be installed onto any deck regardless of deck thickness.

Materials: All parts can be done from stainless steel or brass depending on required outlook, plastic insert, and two plastic washers for latch.

Special thanks to Doug Davey (Doug Davey) for idea of utilising the internal space!