Patent ID: 7387556
Filing Date: 2008-06-17
Classification: B63H

Abstract:
1. A marine propulsion system, comprising: a driveshaft; a housing configured to support said driveshaft for rotation about a generally vertical axis, said housing being rotatably attached to a submerged bottom surface of a marine vessel with said driveshaft extending through said submerged bottom surface; a propeller shaft, said housing being configured to support said propeller shaft for rotation about a generally horizontal axis, said driveshaft being disposed in torque transmitting relation with said propeller shaft; a first propeller attached to said propeller shaft for rotation about said generally horizontal axis and configured to provide a thrust toward said housing when said marine vessel is being propelled in a forward direction; and an exhaust gas passageway extending from a first location above said submerged bottom surface to a second location within a hub of said first propeller; wherein said exhaust gas passageway comprises: an exhaust conduit which is disposed at said first location above said submerged bottom surface; a cavity within said housing; an exhaust passage connected in fluid communication between said exhaust conduit and said cavity; an exhaust channel connected in fluid communication with said cavity and disposed within said housing to direct exhaust gas toward said second location; wherein said exhaust passage comprises: a stationary plate attached to said exhaust conduit; and a rotatable plate attached to said housing for rotation with said housing relative to said stationary plate, said rotatable plate having a rotatable first hole extending therethrough, said stationary plate having a stationary second hole extending therethrough, said first and second holes being shaped to remain in at least partially overlapping relation with each other when said housing rotates relative to said marine vessel, said rotatable first hole being smaller than said stationary second hole.