The decompression screw is usually located at the foot of the mast on windsurf or windfoil boards, and at the front on stand up paddle or surf boards. It may be in the back for some brands.
This screw is very important because the board is built around a polystyrene block. This polystyrene contains air which, depending on the temperature or altitude, will increase in pressure.
When the screw is closed, the pressure rises, the air expands and pushes on the stratum of the board which can end up exploding and tearing the block.
That’s why when you store your float in your car in the sun or when you fly, it’s very important to open this screw.
You can use a screwdriver or a coin to screw in and out Ehen screwing, just crush the gasket, there is no need to over tighten.
The easiest way is to open the decompression screw after the session and close it again before going in the water (to avoid it taking on water)!