JET PROPULSION TYPE PLANING BOAT

摘要

PROBLEM TO BE SOLVED: To provide a small sized planing boat or the like having an exhaust structure which reduces exhausting sound without lowering the capacity of a water jet pump simplified in its composition and excellent in durability. SOLUTION: The small planing boat is provided with an engine E and a water jet pump P, and ejects water compressed and pressurized by the water jet pump from a rear ejection port and is propelled by its reaction. The discharging port of exhaust gas to be discharged via an exhaust pipe from the engine is provided facing outside of the boat. At least one part of a pump sequence 21C of the water jet pump P is formed into a double-wall structure. An exhaust emission introduction port 2 to be connected to the tip end of the exhaust pipe Ep is provided on the outer wall 1o of the double-wall structure, while the exhaust emission discharging port 3 communicating with the exhaust emission introduction port 2 is provided at a portion exposing outside of the boat of the double-wall structure to discharge the exhaust gas to the outside of the boat.