Abstract: An improved hydraulic engine for boats and the like is provided which preferably includes a rearwardly facing concave impingement surface, along with nozzle apparatus for directing a stream of pressurized water against the impingement surface in order to move the boat forwardly through the water. An oppositely oriented, concave, flow-directional surface is disposed in partial opposition to the impingement surface for deflecting non-pressurized water against the impingement surface as the boat moves through the water. The below water portion of the engine is housed in an open-ended casing, and can be rectangular or circular configuration.

Abstract: Oil spill retrieval apparatus of the type employing a floating flexible barrier, has an oil reservoir tank coupled with the barrier in such manner that oil is conveyed from the barrier to the tank by gravity flow. An oil intake tube interconnecting the barrier and storage tank has an outlet coupled with the tank at an elevation below the water surface, and an opposed mouth floatingly supported on the surface of the water in flow communication with the flexible barrier. In preferred forms, the mouth is provided with a one-way gate precluding backflow of collected oil, and has an inflatible bladder permitting selective vertical adjustment of the mouth relative to the flexible barrier and tube outlet. One form of the invention contemplates the use of a buoyant skimmer in combination with the floatingly supported mouth to enhance oil separation in calm water operations.