Provided is a ship propelling apparatus including a rotation shaft on which a rear propeller is fixed; a front propeller rotatably supported on the rotation shaft in front of the rear propeller; and a counter-rotating device through which the rotation shaft passes, which includes a gear box including therein a plurality of gears configured to reverse rotation of the rotation shaft and transfer the reversed rotation to the front propeller, and which is installed in an installation space formed at the rear of a ship. The rotation shaft includes a measurement hole formed to pass through a center of the rotation shaft for centering of the counter-rotating device installed in the installation space; and an individual lubricant path separated from the measurement hole.

Provided is a ship propelling apparatus including a rotation shaft on which a rear propeller is fixed; a front propeller rotatably supported on the rotation shaft in front of the rear propeller; and a counter-rotating device through which the rotation shaft passes, which includes a gear box including therein a plurality of gears configured to reverse rotation of the rotation shaft and transfer the reversed rotation to the front propeller, and which is installed in an installation space formed at the rear of a ship. The rotation shaft includes a measurement hole formed to pass through a center of the rotation shaft for centering of the counter-rotating device installed in the installation space; and an individual lubricant path separated from the measurement hole.

Transmission systems and methods are for a marine propulsion device having an internal combustion engine that drives a propulsor. An input shaft is driven into rotation at a non-zero first rotational speed by the internal combustion engine. An output shaft drives the propulsor into rotation at a non-zero second rotational speed. A planetary gearset transfers power from the input shaft to the output shaft. A band brake is on the planetary gearset. Actuation of the band brake effects a gear change in the planetary gearset. A band brake actuator actuates the band brake to effect the gear change. A controller controls the band brake actuator. Based upon one or more operational characteristics of the marine propulsion device the controller is programmed to control the band brake actuator so that the second rotational speed is less than the first rotational speed.

A distributed propulsion system is described that includes at least one turbine engine including an engine shaft and at least one mechanically driven propulsor, wherein a propulsor shaft of the at least one mechanically driven propulsor is not co-axial with the engine shaft of the at least one turbine engine and is driven by the engine shaft of the at least one turbine engine. The distributed propulsion system further includes at least one generator driven by rotation of at least one of the engine shaft of the at least one turbine engine or the propulsor shaft of the at least one mechanically driven propulsor. The distributed propulsion system also includes at least one electrically driven propulsor, wherein a propulsor motor of the at least one electrically driven propulsor drives a propulsor fan of the at least one electrically driven propulsor based on electricity produced by the at least one generator.

A distributed propulsion system is described that includes at least one turbine engine including an engine shaft and at least one mechanically driven propulsor, wherein a propulsor shaft of the at least one mechanically driven propulsor is not co-axial with the engine shaft of the at least one turbine engine and is driven by the engine shaft of the at least one turbine engine. The distributed propulsion system further includes at least one generator driven by rotation of at least one of the engine shaft of the at least one turbine engine or the propulsor shaft of the at least one mechanically driven propulsor. The distributed propulsion system also includes at least one electrically driven propulsor, wherein a propulsor motor of the at least one electrically driven propulsor drives a propulsor fan of the at least one electrically driven propulsor based on electricity produced by the at least one generator.

A transmission (14) for connecting a propeller (15) to an engine (13) having a drive shaft (2), comprising: a first gear (3) driven by the drive shaft (2) in a first rotational direction; an idler gear (4) driven by the first gear; a third gear (5) driven by the idler gear (4); and an output shaft (6) driven by the third gear in the first rotational direction.

A method for operating a ship propulsion system. A setpoint rotational speed is determined for a propeller shaft and a setpoint pitch angle for an adjustable propeller on a control side based on an adjustable propeller characteristic diagram and an operator. An engine is determined based on a ship's engine characteristic diagram and the setpoint rotational speed for the propeller shaft. An actual engine operating point is determined as a function of a measured actual rotational speed and a measured actual torque, so that when the drive power is constant, the set-point rotational speed for the propeller shaft and the pitch angle for the adjustable propeller can be varied while reducing fuel consumption of the ship's engine and, when this is possible, the setpoint rotational speed for the propeller shaft, the setpoint pitch angle for the adjustable propeller and the setpoint operating point of the ship's engine are adapted.

A method for operating a ship propulsion system. A setpoint rotational speed is determined for a propeller shaft and a setpoint pitch angle for an adjustable propeller on a control side based on an adjustable propeller characteristic diagram and an operator. An engine is determined based on a ship's engine characteristic diagram and the setpoint rotational speed for the propeller shaft. An actual engine operating point is determined as a function of a measured actual rotational speed and a measured actual torque, so that when the drive power is constant, the set-point rotational speed for the propeller shaft and the pitch angle for the adjustable propeller can be varied while reducing fuel consumption of the ship's engine and, when this is possible, the setpoint rotational speed for the propeller shaft, the setpoint pitch angle for the adjustable propeller and the setpoint operating point of the ship's engine are adapted.

A strut mounted gear box for counter rotating propellers. The gear box is strut mounted for securement to the hull of a boat. A main input shaft is coupled to a propulsion component of a boat with a distal end secured to an idler gear cage assembly located within the gear box. The main input shaft transfers torque and rotation from the propulsion component to an idler gear cage assembly. An inner tail shaft is coupled to the main input shaft and arranged to rotate the inner tail shaft in a first direction. A counter shaft is coupled to the idler gear cage assembly and arranged to rotate the counter shaft in a second direction. A first propeller is secured to the inner tail shaft providing rotation in the first direction; and a second propeller is secured to the counter shaft allowing rotation in the second direction.

A gear unit including a gear, a hub, and a support ring configured to reduce the maximum stress on the gear teeth and, in particular, the toe of the gear teeth.