Abstract: A system to adjust to the changing draft of ocean-going ships on the aft seal system equipped with several outwardly-directed gaskets and one inwardly-directed gasket, in which, between each two outwardly-directed gaskets a ring-shaped chamber is reserved, to which a feed line for compressed air is connected. Integrated into the feed line is a pressure control mechanism and a discharge channel which can periodically empty into the interior of the ship (bilge), whereby the pressure in the ring-shaped chamber is always maintained slightly below the outside water pressure. The system is characterized by the fact that an electronic draft measurement system is located on the ship's hull to supply electric signals which correspond to the current draft, which signals actuate the pressure control mechanism.

Abstract: A safety device on an aft seal system equipped with at least two gaskets for a ship's propeller shaft, which propeller shaft is sealed with respect to the outside water and with respect to a lubricant chamber, and on which a ring-shaped chamber is reserved between each two gaskets, to which chamber are connected a feed line for compressed air and a discharge channel which can be emptied by means of a solenoid valve which opens and closes periodically. The pressure in the ring-shaped chamber is kept always slightly lower than the respective outside water pressure and the lubricant pressure by means of a pressure regulation mechanism.