Saare 游艇通风口2型

Finaly it is ready. Main principle is illustrated in the picture. The 'valve' is covered underneath with hard silicon or plastic pads to the size of holes, therefore when closing, it clicks and stays in the position.
Advantages:
1) Totally waterproof
2) Can be italled on any deck regardless thickness
3) Very small size (Due to this principle it is possible to make it very tiny with a lot of air coming in at the same time)

Materials:
Everything from brass or stainless, except valve. Valve is made by hot intrusion of brass (or stainless) plates into the plastic holder, and then pads are glued on closing surface of the plates. Handle cover and indicator can be made of copper.

It is also possible to add a spring behind the cover lid and valve (there is some space disigned for it), in this case the pads can be made thicker, and for opening you just have to push the handle a bit (itead of click). But I am pretty sure it will work with click nicely.