A watercraft steering system includes a reverse reduction transmission and an obstacle detector. The reverse reduction transmission is configured to convert power from a main engine into an output for causing a watercraft to make forward travel, neutral, or reverse travel, so as to control navigation of the watercraft. The obstacle detector is disposed at a hull of the watercraft and is configured to detect an obstacle. The watercraft steering system is configured to, based on a location of the obstacle with respect to the hull, a travel direction of the watercraft, a travel speed of the watercraft, and a distance between the hull and the obstacle, select from among the forward travel, the neutral, and the reverse travel, and maintain the travel speed or change the travel speed.

Power transmission systems including clutch arrangements and systems are adapted to be used in marine and other environments. Such power transmission systems may include clutch arrangements that provide more effective power transmission capabilities as well as greater durability and longer life. Slipping clutch arrangements may effectively vary the output speed of a clutch arrangement from the speed of the engine or other driver as desired for the particular application. Various clutch arrangements also provide for greater flexibility and drive options, lighter weight, and diverse types of capabilities.

Power transmission systems including clutch arrangement and control systems are adapted to be used in numerous different operational environments. Such power transmission systems may include clutch arrangements that provide more effective power transmission capabilities, reduced vibration, greater durability and longer life. Control arrangements are provided to more effectively control and monitor clutch operation in ways that provide for greater system flexibility and drive options. Structures that minimize vibrations may be included in a clutch housing as well as in clutch and separator discs of a disc pack.

In a marine propulsion apparatus that transmits power of at least one of an internal combustion engine (ICE) and a generator motor (GM) mounted on a ship to a propeller via a forward reverse switching mechanism, the marine propulsion apparatus can be downsized as a whole. The marine propulsion apparatus includes a connection switching mechanism capable of selectively connecting the GM to an upstream side and a downstream side of the power transmission from the ICE in the forward reverse switching mechanism. Then, the forward reverse switching mechanism is interposed between the ICE and the connection switching mechanism, and a large torque from the ICE is not directly transmitted to the connection switching mechanism. As a result, it is not necessary to increase the capacity of the connection switching mechanism, and the connection switching mechanism and thus the marine propulsion apparatus can be downsized.

A saildrive arrangement (1) which comprises an upper unit (13) to be positioned inside a hull (5) of a sailboat (7) and a lower unit (14) which is arranged to protrude from the bottom (6) of the hull (5). The upper unit (13) comprises an input shaft (4) to be connected to an engine (2) and the lower unit (14) comprises a propeller shaft (9). A brake (15), for locking the rotational movement of the propeller shaft (9), is located in the upper unit (13). The saildrive arrangement (1) is incorporated into a sailboat (7) with a hull (5) and an engine (2).

A method of operating a marine propulsion system (1) in a trolling mode. The marine propulsion system (1) comprises at least one propeller shaft (6) which can be driven by an engine (2), via a pressure operated forward clutch (4), in a forward direction or, via a pressure operated reverse clutch (5), in a reverse direction. A forward pressure is applied to engage the forward clutch (4) to a certain extent and, at the same time, a reverse pressure is applied to engage the reverse clutch (5) to a certain extent. A value of the forward pressure is different from a value of the reverse pressure so that the propeller shaft (6) is caused to rotate in a desired rotational direction. A control unit with mechanism to operate the marine propulsion system according to the method and a marine propulsion system with such a control unit are also disclosed.

A saildrive arrangement (1) which comprises an upper unit (13) to be positioned inside a hull (5) of a sailboat (7) and a lower unit (14) which is arranged to protrude from the bottom (6) of the hull (5). The upper unit (13) comprises an input shaft (4) to be connected to an engine (2) and the lower unit (14) comprises a propeller shaft (9). A brake (15), for locking the rotational movement of the propeller shaft (9), is located in the upper unit (13). The saildrive arrangement (1) is incorporated into a sailboat (7) with a hull (5) and an engine (2).

Power transmission systems including clutch arrangements and systems are adapted to be used in marine and other environments. Such power transmission systems may include clutch arrangements that provide more effective power transmission capabilities as well as greater durability and longer life. Slipping clutch arrangements may effectively vary the output speed of a clutch arrangement from the speed of the engine or other driver as desired for the particular application. Various clutch arrangements also provide for greater flexibility and drive options, lighter weight, and diverse types of capabilities.

A propulsion system includes an electric motor assembly having an electric motor, a driveshaft, and a disconnect clutch. The disconnect clutch is structured to couple the driveshaft to an engine output shaft. The propulsion system further includes a fluid system having a cooling and lubrication fluid circuit fluidly connected to a first pump, and a clutch actuation fluid circuit fluidly connected to a second pump. The cooling and lubrication fluid circuit is fluidly connected to the clutch actuation fluid circuit via at least one of respective pump outgoing conduits from the first pump and the second pump or respective pump supply conduits to the first pump and the second pump. Related operating methodology is also disclosed.

A reverse gear for watercrafts includes an input shaft that receives rotational power of a main engine. A forward/reverse switching mechanism includes a reduction function and switches the rotational power of the input shaft among forward, neutral, and reverse states. An output shaft outputs the rotational power of the forward/reverse switching mechanism and rotates at a rotational speed that differs from a rotational speed of the input shaft due to the reduction function of the forward/reverse switching mechanism. A reduction mechanism includes a fixed reduction ratio, and reduces the rotational power of the output shaft and transmits the reduced rotational power to a propeller shaft. A forward/reverse housing accommodates the forward/reverse switching mechanism. A reduction housing accommodates the reduction mechanism. The forward/reverse housing and the reduction housing are detachably coupled one behind the other in an axial direction of the output shaft.