Abstract: A water-borne craft is supported by laterally spaced pontoons, wherein an open-topped receptacle mounted in the open space between the pontoons is movable between a fully elevated position wherein the bottom of the receptacle is at or above the water line of the craft and a fully lowered position wherein the bottom of the receptacle is submerged beneath the water line and the open top of the receptacle is above the water line. Water and materials are introduced into and mixed in the receptacle when in a fully lowered position, after which the mixture is pumped from the receptacle and discharged under pressure through a nozzle.