BSS have issued a warning over leaking weed hatches, following a number of recent sinkings.

Owners of boats with weed hatches are being reminded by the Boat Safety Scheme to make a
routine of checking the security of weed hatch covers.

Boaters are particularly vulnerable to this after removal of the hatch to clear the propeller. The water level is normally below the hatch level, but when the propeller is turning, this can pump water through a leaking or mis-fitted seal. It is important to check for leakage soon after setting off. 

You can read the full text of the warning here.