Foot Operated Push Pad
The Club's ship inspectors often report that spring loaded, self closing devices on the engine room sett/serv tanks are found to be lashed or clamped open (ref Good & Bad Practice poster 16, 463kb pdf). On one of our Members' ships the above system is in place. Here, to check the level of the oil in the settling tanks, the seafarer uses his foot to operate a swivelled push pad (coloured green in the above photo). When the foot operated "push pad" is released the spring loaded valve to the tank closes and the push pad returns to the closed position.
(for further ideas covering the same topic click here.
Source UK P&I