Abstract: A pump aggregate is mounted within a bell shape housing member along with a hoisting winch which permits the lowering of the pump aggregate into a hatch of a cargo tank when a hatch cover has been removed. The housing member allows the passage of the pump aggregate into the hatch while maintaining the pressurized conditions of the hatch. A hose stump is disposed in folded manner within the housing member to unfold during lowering of the pump aggregate. The hose stump connects to a coupling on the top of the housing member. A pair of flexible hydraulic conduits which are connected to the pump aggregate also uncoil during lowering of the pump aggregate and, in turn, are connected to coupling arrangements on the housing member. A seal is provided about the open bottom of the housing member to seal against a tank to maintain the pressurized conditions.