A watercraft and a marine engine assembly for pivotably mounting to a watercraft about a tilt-trim axis are disclosed. The marine engine assembly includes an engine unit including: an engine unit housing; an engine disposed in the housing; and an exhaust conduit disposed in the housing, an exhaust inlet defined by the exhaust conduit being fluidly connected to the engine, the exhaust conduit extending forward and upward from the exhaust inlet and then subsequently extending downward and rearward to an exhaust outlet. The marine engine assembly also has a driveshaft operatively connected to the engine and a propulsion device operatively connected to the driveshaft. A center of mass of the engine is disposed below the tilt-trim axis at least when the driveshaft is vertically oriented.

A device and a method for controlling an electrical steering system in a marine vessel comprising at least one steerable propulsion unit, the electrical steering system comprising a main steering system (220; 220.1) that comprises a main electric motor (221; 221.1) and a main power source, e.g. a main battery (229; 229.1); a main steering angle sensor (226; 226.1) arranged to detect the steering angle of the propulsion unit; a main control unit (240; 240.1) arranged to steer the propulsion unit and to monitor the main steering system status; an auxiliary steering system comprising an auxiliary electric motor (231; 231.1) and an auxiliary battery (239; 239.1); and an auxiliary clutch (232; 232.1) arranged to connect a drive shaft of the auxiliary electric motor to the input shaft of the steering transmission (223; 223.1). The method involves the steps of engaging the auxiliary clutch at start-up of the propulsion unit; performing a diagnostic test of the main steering system during start-up; performing a calibration of an auxiliary steering angle sensor; and disengaging the auxiliary clutch upon completion of the diagnostic test.

A ship propulsion machine includes a ship propulsion machine main body and a propulsion module. The ship propulsion machine main body includes a power source, a tank storing cooling liquid, a heat sink cooling the cooling liquid, a cooling liquid passage connecting the power source and the heat sink, a pump causing the cooling liquid to flow in the cooling liquid passage, a first housing part housing the heat sink. The propulsion module includes a drive shaft rotated by the power source and a propulsion device converting rotation of the drive shaft into the propulsion force. A connection mechanism separably connecting an output shaft of the power source and the drive shaft is provided on the power source and on the drive shaft. The first housing part and the propulsion device are provided with an attachment mechanism detachably attaching the propulsion module.

A ship propulsion machine includes a ship propulsion machine main body and a propulsion module. The ship propulsion machine main body includes a power source, a tank storing cooling liquid, a heat sink cooling the cooling liquid, a cooling liquid passage connecting the power source and the heat sink, a pump causing the cooling liquid to flow in the cooling liquid passage, a first housing part housing the heat sink. The propulsion module includes a drive shaft rotated by the power source and a propulsion device converting rotation of the drive shaft into the propulsion force. A connection mechanism separably connecting an output shaft of the power source and the drive shaft is provided on the power source and on the drive shaft. The first housing part and the propulsion device are provided with an attachment mechanism detachably attaching the propulsion module.

An underwater vehicle having a hovering system using a tube type launcher. The underwater vehicle includes a streamlined body and a hovering system connected to a rear of the streamlined body to generate a kinetic force of the streamlined body. The hovering system includes an extension shaft extended to be connected to the rear, a connection assembly connected to the rear through the extension shaft, and an auxiliary propeller assembly connected to the connection assembly.

An outboard motor has a powerhead that causes rotation of a driveshaft, a steering housing located below the powerhead, wherein the driveshaft extends from the powerhead into the steering housing; and a lower gearcase located below the steering housing and supporting a propeller shaft that is coupled to the driveshaft so that rotation of the driveshaft causes rotation of the propeller shaft. The lower gearcase is steerable about a steering axis with respect to the steering housing and powerhead.

A propulsion device for a marine vessel. A base is configured to be coupled to the marine vessel. A shaft includes an upper segment and a lower segment each extending along a length axis, wherein the upper segment is coupled to the base. A propulsor is coupled to the lower segment, where the propulsor is configured to propel the marine vessel in water. A shock absorber includes a resilient member that resiliently couples the upper segment and the lower segment together, where the resilient member dampens impact forces received at the lower segment and reduces transfer of the impact forces to the upper segment.

A propulsion device for a marine vessel. A base is configured to be coupled to the marine vessel. A shaft includes an upper segment and a lower segment each extending along a length axis, wherein the upper segment is coupled to the base. A propulsor is coupled to the lower segment, where the propulsor is configured to propel the marine vessel in water. A shock absorber includes a resilient member that resiliently couples the upper segment and the lower segment together, where the resilient member dampens impact forces received at the lower segment and reduces transfer of the impact forces to the upper segment.

A vessel (1) comprises a hull (2) including a bow (3) and a stern (4) and has a length-to-beam ratio which is smaller than 10:1, preferably smaller than 5:1. The hull (2) has a vertical centre plane (CP) extending in a direction from the bow (3) to the stern (4). At each side of the centre plane (CP) the vessel (1) has at least two azimuth thrusters (6) including respective propellers (6a), which azimuth thrusters (6) are located next to each other in transverse direction of the centre plane (CP). Each azimuth thruster (6) drivably coupled to its own prime mover (7).

A vessel (1) comprises a hull (2) including a bow (3) and a stern (4) and has a length-to-beam ratio which is smaller than 10:1, preferably smaller than 5:1. The hull (2) has a vertical centre plane (CP) extending in a direction from the bow (3) to the stern (4). At each side of the centre plane (CP) the vessel (1) has at least two azimuth thrusters (6) including respective propellers (6a), which azimuth thrusters (6) are located next to each other in transverse direction of the centre plane (CP). Each azimuth thruster (6) drivably coupled to its own prime mover (7).