The blades of the propeller are characterized by a blade center axis which corresponds to a generator line of a cone to which the blade, or blade thrust surface, conforms. The propeller hub is fixed to the blade at the root, in line with the blade center axis, such that the hub axis and blade center axis lie in the same plane, and the leading edge of the blade is positioned forward (referring to the upstream direction of movement caused by the propeller) of the trailing edge of the blade.

The blades of the propeller are characterized by a blade center axis which corresponds to a generator line of a cone to which the blade, or blade thrust surface, conforms. The propeller hub is fixed to the blade at the root, in line with the blade center axis, such that the hub axis and blade center axis lie in the same plane, and the leading edge of the blade is positioned forward (referring to the upstream direction of movement caused by the propeller) of the trailing edge of the blade.

A propeller includes a bushing that rotates together with the propeller shaft, and a propeller damper disposed around the bushing, and an inner cylinder that surrounds the bushing via the propeller damper. The bushing includes a first cylindrical portion surrounding the propeller shaft, and a first protrusion protruding outward from the first cylindrical portion and integral with the first cylindrical portion. The inner cylinder includes a second cylindrical portion surrounding the bushing via the propeller damper and a second protrusion protruding inward from the second cylindrical portion. The inner cylinder is rotatable with respect to the bushing between a noncontact position and a contact position.

A propeller includes a bushing that rotates together with the propeller shaft, and a propeller damper disposed around the bushing, and an inner cylinder that surrounds the bushing via the propeller damper. The bushing includes a first cylindrical portion surrounding the propeller shaft, and a first protrusion protruding outward from the first cylindrical portion and integral with the first cylindrical portion. The inner cylinder includes a second cylindrical portion surrounding the bushing via the propeller damper and a second protrusion protruding inward from the second cylindrical portion. The inner cylinder is rotatable with respect to the bushing between a noncontact position and a contact position.

A propulsion system comprises a propeller and a driving device coupled with the propeller. The propeller comprises a hub having a receiving hole, a plurality of blades connected to the hub, and a connecting surface. The driving device comprises a body portion, an elastic abutting member disposed on the body portion and configured to abut against the connecting surface, and a lock portion disposed on the body portion and including a first snap-fitting portion. A second snap-fitting portion is arranged on an inner wall of the receiving hole and is configured to snap with the first snap-fitting portion.

A propulsion system comprises a propeller and a driving device coupled with the propeller. The propeller comprises a hub having a receiving hole, a plurality of blades connected to the hub, and a connecting surface. The driving device comprises a body portion, an elastic abutting member disposed on the body portion and configured to abut against the connecting surface, and a lock portion disposed on the body portion and including a first snap-fitting portion. A second snap-fitting portion is arranged on an inner wall of the receiving hole and is configured to snap with the first snap-fitting portion.

A marine propeller includes a plurality of blades attached to a hub, with a disk area ratio of approximately 50%, a blade area ratio of approximately 61%, a blade rake angle of approximately 26.5 degrees, a blade skew angle of approximately 0 degrees, and wherein the angle between the chord line at any given radius r on said blades with a line that is parallel to the propeller axis of rotation and intersects the chord line, is equal to tan.sup.−1(2πNr/Vo)−α, where N is the rotational speed of the propeller at a selected design condition, Vo is the speed of the water entering the propeller (i.e. the speed of the vessel) at the design condition, and α is the angle of attack at the radius r at said design condition, and where a is generally constant across most or all of the span of the blades at the design condition, and where the value of α may be selected to be lower near the hub than for the remainder of blade, and where additional camber is provided in the leading edge region, such that leading edge camber line angle of attack is reduced relative to the chord line angle of attack for the overall blade section.

A marine propeller includes a plurality of blades attached to a hub, with a disk area ratio of approximately 50%, a blade area ratio of approximately 61%, a blade rake angle of approximately 26.5 degrees, a blade skew angle of approximately 0 degrees, and wherein the angle between the chord line at any given radius r on said blades with a line that is parallel to the propeller axis of rotation and intersects the chord line, is equal to tan.sup.−1(2πNr/Vo)−α, where N is the rotational speed of the propeller at a selected design condition, Vo is the speed of the water entering the propeller (i.e. the speed of the vessel) at the design condition, and α is the angle of attack at the radius r at said design condition, and where a is generally constant across most or all of the span of the blades at the design condition, and where the value of α may be selected to be lower near the hub than for the remainder of blade, and where additional camber is provided in the leading edge region, such that leading edge camber line angle of attack is reduced relative to the chord line angle of attack for the overall blade section.

A driving device includes a body portion, a driving shaft disposed on the body portion and configured to rotate relative to the body portion, a lock portion disposed on the body portion and including a snap-fitting portion configured to snap with the propeller, and an elastic abutting member disposed on the body portion and configured to be pressed down and deformed along a direction parallel to the driving shaft to abut against a propeller in response to the snap-fitting portion being snapped with the propeller.

A driving device includes a body portion, a driving shaft disposed on the body portion and configured to rotate relative to the body portion, a lock portion disposed on the body portion and including a snap-fitting portion configured to snap with the propeller, and an elastic abutting member disposed on the body portion and configured to be pressed down and deformed along a direction parallel to the driving shaft to abut against a propeller in response to the snap-fitting portion being snapped with the propeller.