Disclosed are a propulsion device for a ship and a ship having the same. The propulsion device may include a rotational shaft, a rear propeller fixed to the rotational shaft, a front propeller rotatably supported by the drive shaft in front of the rear propeller, a counter rotation unit disposed in an installation space of a stern of a ship body and including a plurality of gears configured to reverse rotation of the rotational shaft and transmit the reversed rotation to the front propeller and a gear box configured to receive the plurality of gears, a coupling unit configured to separably connect the rotational shaft with the counter rotation unit and cut off power transmission from the rotational shaft to the counter rotation unit upon disconnection therebetween, and a rotation preventing unit configured to prevent rotation of the front propeller when the coupling unit is separated.

The outboard motor includes a lower unit that rotatably supports a propeller shaft and a shift unit that switches a shift position. A drive shaft that transmits rotational power to the propeller shaft has upper and lower drive shafts provided coaxially and in series, end to end. The shift unit has an upper gear rotating in synchronization with the upper drive shaft, a lower gear provided rotatably with respect to the lower drive shaft, an intermediate gear that transmits rotation of the upper gear to the lower gear, and a bearing that rotatably supports the middle shaft provided with the intermediate gear. The intermediate gear and the bearing are modularized and are detachably installed to the lower unit.

Disclosed are a propulsion device for a ship and a ship having same. The propulsion device, according to an embodiment of the present invention, comprises: a rear propeller fixed to a driveshaft; a front propeller positioned in front of the rear propeller, and supported rotably on the driveshaft; and a counter rotation device for reversing and transmitting the rotation of the driveshaft to the front propeller; a motor for rotating the driveshaft; and an housing, which extends from to the lower part of the hull, and which is installed so as to envelope the counter rotation device and the motor.

A system for providing marine propulsion is provided including an input shaft driven by a prime mover, a pinion gear coupled to the input shaft, a plurality of planet gears coupled to the pinion gear, a planet carrier having the plurality of planet gears rotationally mounted thereto, and a ring gear surrounding the planet gears and coupled thereto. The planet carrier and ring gear are coupled to internal and external output shafts that are coaxially aligned, which are coupled to aft and forward propulsor elements. The ring gear and planet carrier rotate in opposite directions to provide contra-rotating forward and aft propulsor elements. The ring gear and planet gear are each coupled to rotation altering devices that, when at least one is activated, the rotation of both the planet carrier and ring gear will be altered, thereby altering the rotation of the propulsor elements.

A duo propeller disclosed having a forward propeller having increased loading distribution and high swirl near the tip. The duo propeller has an aft propeller with a more optimal loading distribution that can cancel the high tip swirl from the forward propeller. The duo-propeller an enhanced ability for the aft propeller to capture the energy lost to the swirling flow of the forward propeller's outflow.

A duo propeller disclosed having a forward propeller having increased loading distribution and high swirl near the tip. The duo propeller has an aft propeller with a more optimal loading distribution that can cancel the high tip swirl from the forward propeller. The duo-propeller an enhanced ability for the aft propeller to capture the energy lost to the swirling flow of the forward propeller's outflow.

The purpose of the present disclosure is to provide a hull-directed propulsion system of a contra-rotating propeller and a method for manufacturing the same, in which the contra-rotating propulsion unit mounted on an electric propulsion vessel is directly connected to the hull, thereby significantly improving the propulsion efficiency of the electric propulsion vessel. In order to achieve the purpose, the present disclosure provides a hull-directed propulsion system of a contra-rotating propulsion unit, comprising: a contra-rotating propulsion unit including a front propeller and a rear propeller; a dual-rotor electric motor configured to generate rotational directions of the front propeller and the rear propeller, respectively; and a dual shaft connecting the contra-rotating propulsion unit and the dual-rotor electric motor.

A marine propeller combination for a marine propulsion unit includes a first propeller and a second propeller arranged to rotate simultaneously in opposite directions about a common rotational axis. The marine propeller combination is configured such that the first and second propellers are angularly positioned such that during one revolution one of the blades of the first propeller is aligned with a drive leg of the marine propulsion unit when a blade gap of the second propeller is aligned with the drive leg, or one of the blades of the first propeller is aligned with the drive leg when one of the blades of the second propeller is aligned with the drive leg. The disclosure further relates to a marine vessel and to a method of operating a marine propeller combination.

A marine drive unit for a marine vessel has a shaft housing having a housing face and a rotatable shaft having an outer shaft face. The rotatable shaft is rotatable arranged within the shaft housing whereby an annulus is defined between the housing face and the outer shaft face. The shaft housing has an inlet being in fluid communication with the annulus so that a lubrication can be introduced in the annulus. One or more spacer element(s) is/are arranged at the inlet for at least dividing the annulus up in several parts around the inlet.

A marine drive assembly has a housing extending along a central axis and defining a gearbox section and a driveshaft section. A bevel gear assembly is housed in the gearbox section and has a first bevel gear rotatable about a central axis, a second bevel gear rotatable about the central axis, and a third bevel gear rotatable about a radial axis and operatively engaging the first bevel gear and the second bevel gear. A mounting flange is connected to and extends around at least part of the gearbox section. An inner shaft extends along the central axis and is operably connected to the first bevel gear for rotation in a first rotational direction about the central axis. An outer shaft is coaxially arranged with the inner shaft and operably connected to the second bevel gear for rotation in an opposite second rotational direction about the central axis.