When water has been pumped out on the inside and the pressure difference is acting on the sea chest cover, the rubber gasket will be compressed further. The springs under the wing nuts maintain a constant tension in the rods as this happens, by compensating for the movement of the cover. This means that the divers do not need to go back and re-tighten the wing nuts after emptying the sea chest.
Miko’s Sea Chest Covers will keep the sea chest dry throughout the entire operation.