Boat motor : 4-stroke out-board motor 40 hp (hydrojet)
OTPIMAX SPORT Mercury Outboards Europe

Mercury Jet Outboards are designed with the power and the weight to cover any shallow-water jet boat application. Our FourStroke jet outboards are electronic fuel injected, with a range from 25 to 40 horsepower. Mercury’s jet-drive outboards are specifically designed to pilot boats in shallow waters where propeller-driven hulls are unable to operate. Because there is no lower unit extending below the hull, the jet drive permits passage over obstacles that would foul a propeller-driven outboard boat.
Operation
Water is drawn into the unit through the intake grill by an impeller, driven directly by the engine driveshaft. The water is then forced at high pressure through an outlet nozzle, creating thrust that drives the boat forward. To obtain reverse, a gate lifts into position over the outlet re-directing the pressure stream in the opposite direction