Abstract: A propeller includes a propeller shaft, a plurality of first blades, and a plurality of second blades. The first blades are connected to the outer peripheral surface of the propeller shaft so as to be rotated synchronously with the propeller shaft. The second blades are connected to the outer peripheral surface of the propeller shaft, so that they are rotated in the same direction as the first blades. The second blades are located in front of the first blades and correspond to the first blades in a one-to-one manner. The size of the second blades is smaller than the size of the first blades, and the rotation direction of the second blades is the same as the rotation direction of the first blades. Thereby, the propeller of the present invention can improve the operation efficiency of the boat at high speed without increasing the size of the first blades.

Abstract: A built-in propulsion system includes an engine, a diversion unit with a diversion base and an exhaust pipe, and a propulsion unit. The diversion base is connected to the engine, having a water inlet, a water outlet, a diversion channel in communication between the water inlet and the water outlet, a shaft hole above the water inlet and an exhaust chamber behind the shaft hole. The exhaust pipe is fixed on the outer periphery surface of the diversion base in communication with the exhaust chamber. The propulsion unit includes a transmission shaft inserted through the shaft hole and connected to the engine, and an impeller located in the diversion channel and connected to the transmission shaft. The exhaust pipe is used to exhaust the exhaust gas of the engine to the outside of the diversion base to avoid the interference of the exhaust gas and the water flow.

Abstract: A marine propulsion system includes a water intake guide block with a flow guide passage, a propulsion device including a housing connected to the water intake guide block and a propeller mounted in the housing, a fixed nozzle connected to the housing of the propulsion device, a swinging nozzle connected to the fixed nozzle and biasable leftward and rightward relative to the fixed nozzle, and a contra type bossing pivotally connected to the fixed nozzle and biasable up and down relative to the fixed nozzle. When rotating the propeller, water is sucked into the flow guide passage and propelled by the propeller to eject backward through the fixed nozzle, and the swinging nozzle is biased leftward/rightward to control leftward/rightward turning of the boat, and the contra type bossing is biased upward/downward to control the pitch angle of the boat and forward/backward movement of the boat.

Abstract: A marine propeller having multiple adjustable exhaust structures is disclosed. Each adjustable exhaust structure includes an exhaust unit with exhaust through holes cut through the outer surface and inner surface of the propeller hub of the marine propeller, an adjustment member with shielding portions mounted in the exhaust unit, and a fastening member for locking the adjustment member to the exhaust unit. The adjustment member is movable to adjust the shielding area of the shielding portions relative to the exhaust through holes when disengaged from the constraint of the fastening member. Thus, the exhaust volume is adjustable to fit different conditions without changing any component parts of the marine propeller, facilitating ease of use of the marine propeller.

Abstract: A marine propeller having multiple adjustable exhaust structures is disclosed. Each adjustable exhaust structure includes an exhaust hole unit with exhaust through holes cut through the outer surface and inner surface of the propeller hub of the marine propeller, an adjustment member with shielding portions mounted in the exhaust hole unit, and a fastening member for locking the adjustment member to the exhaust hole unit. The adjustment member is movable to adjust the shielding area of the shielding portions relative to the exhaust through holes when disengaged from the constraint of the fastening member. Thus, the exhaust volume is adjustable to fit different conditions without changing any component parts of the marine propeller, facilitating ease of use of the marine propeller.

Abstract: An electric outboard drive adapted to be mounted on a transom of a boat through a mounting bracket includes a driving device and a propelling device. Through engagement of a first transmission shaft with a second transmission shaft, the power of an electric motor of the driving device is transmitted to a propeller of the propelling device. As a result, when the electric motor drives the first transmission shaft to rotate, the propeller is rotated by the transmission of the second transmission shaft to propel the boat.

Abstract: An electric outboard drive adapted to be mounted on a transom of a boat through a mounting bracket includes a driving device and a propelling device. Through engagement of a first transmission shaft with a second transmission shaft, the power of an electric motor of the driving device is transmitted to a propeller of the propelling device. As a result, when the electric motor drives the first transmission shaft to rotate, the propeller is rotated by the transmission of the second transmission shaft to propel the boat.

Abstract: A propeller for a boat includes a hub having a tail portion with an outlet, and a plurality of blades equiangularly disposed on the hub. The outer periphery of the tail portion defines with a center axis of the hub a distance gradually decreasing toward the outlet. Thus, the propeller has the advantages of reducing the drag and increasing the propulsive force of the boat when it rotates.

Abstract: A marine propelling system for a boat includes a guide shell having a guideway for guiding a water flow to pass therethrough; a propelling member having a main body and a propeller; a vortex guide member mounted to an outlet of the main body and extending backward; a horizontally steering ring sleeved onto a peripheral edge of a front section of the vortex guide member, a vertically steering ring sleeved onto a peripheral edge of a rear section of the vortex guide member; and an inverted guide hood mounted to a rear side of the vortex guide member. When the propeller is rotated, a water flow enters through the guideway and is then pressurized by the propeller to become a vortex flow ejected outward for providing the boat with a propulsive force. In this way, marine propelling system can greatly enhance the steering maneuverability and the safety of the boat.

Abstract: A propeller for a boat includes a hub having a tail portion with an outlet, and a plurality of blades equiangularly disposed on the hub. The outer periphery of the tail portion defines with a center axis of the hub a distance gradually decreasing toward the outlet. Thus, the propeller has the advantages of reducing the drag and increasing the propulsive force of the boat when it rotates.

Abstract: A propeller system for a boat includes a housing adapted to be mounted to a stern of the boat and having a receiving chamber inside and waterway at the bottom side thereof, a propeller rotatably disposed in the waterway of the housing, a driving device mounted in the receiving chamber of the housing and having a driving member and a linking member pivotally coupled to the driving member, and a guide ring connected to the linking member of the driving device and located in the waterway of the housing in such a way that the guide ring surrounds the blades of the propeller and is pivotable relative to the propeller. Thus, the propelling system has the advantage of increasing the utilization of the internal space of the boat.

Abstract: A propelling system for a boat includes a housing adapted to be mounted to a stem of the boat and having a receiving chamber inside and a waterway at a bottom side thereof, a propeller rotatably disposed in the waterway of the housing, a driving device mounted in the receiving chamber of the housing and having a driving member and a linking member pivotally coupled to the driving member, and a guide ring connected to the linking member of the driving device and located in the waterway of the housing in such a way that the guide ring surrounds blades of the propeller and is pivotable relative to the propeller. Thus, the propelling system has the advantage of increasing the utilization of the internal space of the boat.

Abstract: A propulsion system for a watercraft includes a concavity formed in a hull of the watercraft. The concavity has a minimum depth at its leading end and a maximum depth at its trailing end. An impeller is mounted in the trailing end of the concavity and a stator trails the impeller. A nozzle having a radius only slightly less than a radius of the impeller is disposed in trailing relation to the stator. An elongate drive shaft extends from an engine mounted fore of the concavity to the impeller. An intake grate is disposed in a mouth of the concavity. Water flowing through the intake grate flows through the concavity in a laminar flow and encounters no obstacles other than the elongate drive shaft before encountering the impeller.

Abstract: A boat propeller comprises a hub formed of a front cylindrical member and a rear cylindrical member. The hub is provided in the joining place with a plurality of receiving cavities which are arranged equiangularly and circularly. Each cavity is provided removably with an angle setting member which is joined with the hub. A plurality of blades are joined with the outer periphery of the hub such that the inner ends of the blades are inserted into the cavities and are located by the angle setting members. Under the circumstance that the shapes of the hub and the blades remain unchanged, the blade pitch in relation to the hub can be changed by the angle setting members of various shapes.