Exhaust system for small planing boat
First Claim
1. An exhaust system for a watercraft having a hull with an undersurface which is wetted during normal operation of said watercraft, an inboard engine mounted within said hull and driving a propulsion drive for propelling said hull through a body of water, an exhaust system for receiving exhaust gases from said engine and discharging the exhaust gases to the atmosphere, said exhaust system terminating in a downwardly facing exhaust outlet extending through said hull under surface, and an expansion chamber communicating with said exhaust system at a point above the water level and devoid of water when the watercraft is operating in the body of water for receiving water which may enter the exhaust system through the exhaust outlet when the watercraft is inverted and to receive any water in said exhaust system when said watercraft is inverted and for draining of such received water back to the body of water in which the watercraft is operating through said exhaust system exhaust outlet when the watercraft is righted for precluding water from entering the exhaust ports of the engine.
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Abstract
A number of embodiments of exhaust systems for marine watercraft, particularly, those of the jet propelled type. The exhaust systems all include an exhaust pipe which terminates in a discharge opening formed in a lower surface of the hull for discharging exhaust gases through the body of water in which the watercraft is operating. In addition, the exhaust pipe has an ascending and descending section with an expansion chamber communicating with the upper portion thereof through an opening so as to accumulate water if the watercraft becomes inverted and to direct the accumulated water back to the exhaust outlet opening when righted so as to preclude water from flowing to the exhaust ports of the engine. The expansion chamber also acts as a silencing device and may comprise a portion of a Helmholtz resonator. Furthermore, a low speed exhaust gas discharge extends from the highest portion of the exhaust pipe to the tunnel in which the jet propulsion unit is contained above the water level therein so as to provide a low speed exhaust gas discharge for discharging exhaust gases when the watercraft is operating at idle or low speeds. Various embodiments show different numbers of Helmholtz resonators and arrangements wherein the low speed exhaust gas discharge communicates with at least one of the Helmholtz resonators.
60 Citations
48 Claims
- 1. An exhaust system for a watercraft having a hull with an undersurface which is wetted during normal operation of said watercraft, an inboard engine mounted within said hull and driving a propulsion drive for propelling said hull through a body of water, an exhaust system for receiving exhaust gases from said engine and discharging the exhaust gases to the atmosphere, said exhaust system terminating in a downwardly facing exhaust outlet extending through said hull under surface, and an expansion chamber communicating with said exhaust system at a point above the water level and devoid of water when the watercraft is operating in the body of water for receiving water which may enter the exhaust system through the exhaust outlet when the watercraft is inverted and to receive any water in said exhaust system when said watercraft is inverted and for draining of such received water back to the body of water in which the watercraft is operating through said exhaust system exhaust outlet when the watercraft is righted for precluding water from entering the exhaust ports of the engine.
- 12. An exhaust system for a watercraft having a hull with a tunnel formed at the rear thereof and surrounded on its sides by an undersurface which is wetted during normal operation of said watercraft, an inboard engine mounted within said hull forwardly of said tunnel, a jet propulsion unit contained within said tunnel and driven by said engine for propelling said hull through a body of water, an exhaust system for receiving exhaust gases from said engine and discharging the exhaust gases to the atmosphere, said exhaust system terminating in a downwardly facing exhaust outlet extending through said hull undersurface on one side of said tunnel, and an expansion chamber within said hull communicating with the exhaust system at a point above the water level when the watercraft is operating in the body of water for receiving water which may enter the exhaust system through the exhaust outlet when the watercraft is inverted and for draining of the received water from said expansion chamber back to the body of water in which the watercraft is operating when the watercraft is righted for precluding water from entering the exhaust ports of the engine.
- 23. An exhaust system for a watercraft having a hull, an inboard engine mounted within said hull and driving a propulsion device for propelling said hull through a body of water, and an exhaust system for receiving exhaust gases from said engine and delivering the exhaust gases to the atmosphere through an exhaust outlet opening, an expansion chamber positioned above a portion of said exhaust system and above the water level in the normal position of said watercraft and normally devoid of water and communicating with said portion of said exhaust system through an opening to function as a silencing device during normal watercraft operation and to absorb a volume of water entering said exhaust system through said exhaust outlet opening when said watercraft is inverted for precluding such water from flowing into the engine upon righting to drain said absorbed volume of water through said exhaust outlet opening upon righting.
- 41. A jet propelled watercraft comprising a hull defining a tunnel portion on its undersurface, a jet propulsion unit mounted in said tunnel, an engine mounted within said hull and driving said jet propulsion unit for powering said watercraft, an exhaust system for discharging exhaust gases from said engine to the atmosphere comprising a high speed exhaust gas discharge terminating in a discharge opening in said hull below the level of water in which the watercraft is operating under all normal watercraft operating conditions, and a low speed exhaust gas discharge communicating said exhaust system with said tunnel at a point above the water level therein under all normal running conditions of said watercraft.
Specification