A propulsion device includes an upper case, a propulsion motor accommodated in the upper case, a lower case supported by the upper case so as to turn around a turning axis, a propulsor supported by the lower case and configured to rotate around a propulsion axis by a driving force of the propulsion motor, a deceleration mechanism provided on a driving force transmission path from the propulsion motor to the propulsor and configured to decelerate rotation of the propulsion motor, and a refrigerant supply mechanism configured to supply a refrigerant to the deceleration mechanism. The lower case includes a turning portion having a cylindrical shape centered on the turning axis, the deceleration mechanism and the refrigerant supply mechanism are arranged on an inner circumference of the turning portion, and a refrigerant suction port of the refrigerant supply mechanism is formed in the turning portion.

A computer-implemented method for maneuvering a boat provided with a single drive unit, includes: Obtaining net momentum direction data indicative of a target horizontal rotational movement of the hull, triggering a series of bursts of thrust by the drive unit, said series of bursts of thrust comprising a plurality of primary bursts and a plurality of secondary bursts directed differently than the primary bursts, The primary bursts and the secondary bursts are directed such that they provide a respective longitudinal thrust component parallel to a hull longitudinal axis. The primary bursts are directed such that the longitudinal thrust components of the primary bursts act in the opposite direction with respect to the direction of the longitudinal thrust components of the secondary bursts. The primary bursts and the secondary bursts are further directed such that they jointly provide a net momentum on the hull associated with said net momentum direction data.

An outboard motor includes a bracket, an outboard motor main body including an upper portion attachable to a hull via the bracket and a lower portion located below the upper portion and on which a propeller is provided, a first steering mechanism to rotate the upper portion in a right-left direction with respect to the hull, and a second steering mechanism to rotate the lower portion in the right-left direction with respect to the upper portion.

An outboard motor includes a cooling device which includes a supply passage supplying a cooling water taken into a lower unit to a cooling mechanism. A first shaft portion of the connecting mechanism has a cylindrical shape, is provided in an upper part of the lower unit, and has an axis coaxial with the axis of a drive shaft. A second shaft portion has a cylindrical shape, is provided in a lower part of an upper unit, and has an axis coaxial with the axis of the drive shaft. One shaft portion of the first and the second shaft portions is inserted into the other shaft portion to be pivotable relative to the other shaft portion. The drive shaft is inserted into the one shaft portion with a space. A part of the supply passage is formed of the space between the drive shaft and the one shaft portion.

A marine propulsion device includes a motor including an output shaft, a drive shaft extending in a vertical direction of the marine propulsion device, and a cooling device. The motor is disposed so that an extension direction of the output shaft is a direction perpendicular to the vertical direction. The cooling device includes an intake port taking water outside the marine propulsion device into the marine propulsion device, a motor water jacket provided in the motor and cooling the motor, a water pump disposed below the motor and sending water taken into the marine propulsion device from the intake port to the motor water jacket as cooling water, and a first cooling water passage connecting a discharge port of the water pump to an inlet port of the motor water jacket.

A marine propulsion device for propelling a boat is provided The marine propulsion device includes a motor including an output shaft, a drive shaft configured to rotate upon receiving a rotation of the output shaft, a propeller shaft provided with a propeller and configured to be rotated upon receiving a rotation of the drive shaft, and a cooling device. The cooling device includes a cooling mechanism configured to cool the motor, and a water pump configured to send water outside the marine propulsion device to the cooling mechanism. An impeller of the water pump is connected via a one-way clutch to the output shaft, the drive shaft, or a rotation transmission member other than the drive shaft provided in the marine propulsion device and configured to rotate by the rotation of the output shaft.

An outboard motor includes an upper unit including a drive motor and a first transmission mechanism, a lower unit including a propeller and a propeller shaft, a drive shaft extending from the upper unit to the lower unit, a connecting mechanism that connects the lower unit to the upper unit so that the lower unit is pivotable, a steering motor serving as a power source for pivoting the lower unit relative to the upper unit, and a third transmission mechanism that transmits rotation of the steering motor to the lower unit. The drive shaft is disposed in front of an output shaft of the drive motor and the steering motor is disposed below the drive motor and behind the drive shaft.

An outboard motor includes an upper unit including a drive motor and a first transmission mechanism, a lower unit including a propeller and a propeller shaft, a drive shaft extending from the upper unit to the lower unit, a connecting mechanism that connects the lower unit to the upper unit so that the lower unit is pivotable, a steering motor serving as a power source for pivoting the lower unit relative to the upper unit, and a third transmission mechanism that transmits rotation of the steering motor to the lower unit. The drive shaft is disposed in front of an output shaft of the drive motor and the steering motor is disposed below the drive motor and behind the drive shaft.

A tiller is for controlling a marine drive. The tiller has a base bracket assembly and a tiller arm which is extends outwardly from the base bracket assembly. The base bracket assembly is configured to facilitate yaw adjustment of the tiller arm, in particular into and between a variety of yaw positions relative to the base bracket assembly. The tiller arm has a grip restraining device which is located on the bottom of the middle portion of the tiller arm and is manually accessible from both sides of the tiller arm. The grip restraining device is specially configured to selectively restrain rotation of a hand grip on the outer end of the tiller arm. The tiller arm also has a tilt mechanism which facilitates tilting of the tiller arm relative to the base bracket assembly into and between a variety of tilt positions, including a straight upward tilt position and a straight downward tilt position.

A tiller is for controlling a marine drive. The tiller has a base bracket assembly and a tiller arm which is extends outwardly from the base bracket assembly. The base bracket assembly is configured to facilitate yaw adjustment of the tiller arm, in particular into and between a variety of yaw positions relative to the base bracket assembly. The tiller arm has a grip restraining device which is located on the bottom of the middle portion of the tiller arm and is manually accessible from both sides of the tiller arm. The grip restraining device is specially configured to selectively restrain rotation of a hand grip on the outer end of the tiller arm. The tiller arm also has a tilt mechanism which facilitates tilting of the tiller arm relative to the base bracket assembly into and between a variety of tilt positions, including a straight upward tilt position and a straight downward tilt position.