A blade member includes a leading edge, a trailing edge, and a blade body extending therebetween. The blade member also includes a dovetail, a transition region, and a transition relief. The dovetail includes a dovetail chord line extending between an axially forward face of the dovetail and an axially aft face of the dovetail. The dovetail chord line has a dovetail chord length. The transition region is formed between the blade body and the dovetail. The blade body and the transition region form a blade body transition chord line at the interface of the blade body and the transition region which has a blade body transition chord length. The transition relief includes a geometric relief in at least one of a forward and an aft end of the transition region and the dovetail. The dovetail chord length is less than the blade body transition chord length.

A peller device with a flap is an apparatus used to enhance the capabilities and efficiency of water circulation and aeration systems. The apparatus is configured to act as both a propeller and an impeller as necessary for a particular water circulation requirement. A flap is an addition to the blade tip which propels a fluid by pushing against the fluid, thus enabling the peller to function as a propeller. In addition, the flap facilitates the generation of a sucking force so the peller can also function efficiently as an impeller. The peller assembly can be encased in circular housings having a vertical axis in which the peller assembly is mounted for rotation on the central axis of the housing. The peller assembly is formed with a hub and a plurality of blades symmetrically positioned around the hub. The flap of the apparatus is attached to the base of the peller assembly.

A method of making a propeller includes forming the propeller to have blades coupled to an outer hub, the outer hub coupled to an inner hub via ribs, and the inner hub configured to be coupled to the marine vessel. The ribs each have first and second ends with a midpoint therebetween, an inner end and an outer end that define a width therebetween, and a leading surface and a trailing surface that define a thickness therebetween. The ribs are tapered such that the thickness is greater at the midpoint than at least at one of the first end and the second end, and scalloped such that the width is greater at the midpoint than at least at one of the first end and the second end. Each of the ribs is coupled to the outer hub in radial alignment with one of the blades.

A method of making a propeller includes forming the propeller to have blades coupled to an outer hub, the outer hub coupled to an inner hub via ribs, and the inner hub configured to be coupled to the marine vessel. The ribs each have first and second ends with a midpoint therebetween, an inner end and an outer end that define a width therebetween, and a leading surface and a trailing surface that define a thickness therebetween. The ribs are tapered such that the thickness is greater at the midpoint than at least at one of the first end and the second end, and scalloped such that the width is greater at the midpoint than at least at one of the first end and the second end. Each of the ribs is coupled to the outer hub in radial alignment with one of the blades.

A propeller assembly is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller assembly includes a hub structure having a plurality of circumferentially spaced blades projecting therefrom and an inner surface defining a passage. An adaptor is receivable in the passage of the hub structure. The adaptor a plurality of key pairs extending along the outer surface thereof the adaptor which define slots for receiving inserts therein. An inner portion of the first side of each insert forms mating relationship with first portion of the first sidewall of a first key of a corresponding key pair and an inner portion of the second side of the insert forms a mating relationship with the first portion of the second sidewall of a second key of the corresponding key pair with the insert received in the corresponding slot.

A propeller assembly is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller assembly includes a hub structure having a plurality of circumferentially spaced blades projecting therefrom and an inner surface defining a passage. An adaptor is receivable in the passage of the hub structure. The adaptor a plurality of key pairs extending along the outer surface thereof the adaptor which define slots for receiving inserts therein. An inner portion of the first side of each insert forms mating relationship with first portion of the first sidewall of a first key of a corresponding key pair and an inner portion of the second side of the insert forms a mating relationship with the first portion of the second sidewall of a second key of the corresponding key pair with the insert received in the corresponding slot.

A boat propeller includes a gear box, an impeller, a stream-guiding ring, and a stream-shaping nozzle. The gear box has a casing and a transmission shaft partially received in the casing. The impeller has an impeller shaft and vanes. The impeller shaft has a hollow columnar outer shaft housing and a hollow columnar inner shaft housing. The inner and outer shaft housings are connected using a plurality of rib portions. The inner shaft housing is further connected to the transmission shaft of the gear box. The vanes are integrated formed on an outer peripheral surface of the outer shaft. The stream-guiding ring is assembled to the casing of the gear box to house the impeller. The stream-shaping nozzle is connected to a rear end of the stream-guiding ring for providing stream-shaping effects. Thereby, the boat propeller has its water inlet diameter maximized, which helps to improve propulsive efficiency.

A boat propeller includes a gear box, an impeller, a stream-guiding ring, and a stream-shaping nozzle. The gear box has a casing and a transmission shaft partially received in the casing. The impeller has an impeller shaft and vanes. The impeller shaft has a hollow columnar outer shaft housing and a hollow columnar inner shaft housing. The inner and outer shaft housings are connected using a plurality of rib portions. The inner shaft housing is further connected to the transmission shaft of the gear box. The vanes are integrated formed on an outer peripheral surface of the outer shaft. The stream-guiding ring is assembled to the casing of the gear box to house the impeller. The stream-shaping nozzle is connected to a rear end of the stream-guiding ring for providing stream-shaping effects. Thereby, the boat propeller has its water inlet diameter maximized, which helps to improve propulsive efficiency.

To provide a propeller for a boat propulsion apparatus, which propeller is excellent in maintainability including easy assembly and easy disassembly and reliably reduces the impact force caused by colliding with an obstacle and transmitted to the hub and the output shaft of the boat propulsion apparatus. The propeller includes: a shaft sleeve insertably and removably fixed to an output shaft of the boat propulsion apparatus; a plurality of blade components that are individually supported by the shaft sleeve and are arranged at intervals in a rotation direction of the output shaft; and a plurality of dampers disposed in such a manner that each of the plurality of dampers is disposed between adjacent two of the plurality of blade components.

To provide a propeller for a boat propulsion apparatus, which propeller is excellent in maintainability including easy assembly and easy disassembly and reliably reduces the impact force caused by colliding with an obstacle and transmitted to the hub and the output shaft of the boat propulsion apparatus. The propeller includes: a shaft sleeve insertably and removably fixed to an output shaft of the boat propulsion apparatus; a plurality of blade components that are individually supported by the shaft sleeve and are arranged at intervals in a rotation direction of the output shaft; and a plurality of dampers disposed in such a manner that each of the plurality of dampers is disposed between adjacent two of the plurality of blade components.