A water drone capable of navigating on the surface, or below the surface, of a body of water. In some embodiments such a vehicle is light-weight, electric-powered, and propeller-driven, and may be operated by remote control from the shore and guided with simple autopilot commands. The vehicle may have two actuators at the rear of the vehicle, each including a motor and a propeller, and each capable of producing forward or reverse thrust. The vehicle may be capable of travelling horizontally through the surf zone and diving vertically through the water column to the seafloor. The vehicle may monitor its own location and depth and may measure environmental conditions such as water temperature; such measurements may be communicated back to the operator using a telemetry system.

A water drone capable of navigating on the surface, or below the surface, of a body of water. In some embodiments such a vehicle is light-weight, electric-powered, and propeller-driven, and may be operated by remote control from the shore and guided with simple autopilot commands. The vehicle may have two actuators at the rear of the vehicle, each including a motor and a propeller, and each capable of producing forward or reverse thrust. The vehicle may be capable of travelling horizontally through the surf zone and diving vertically through the water column to the seafloor. The vehicle may monitor its own location and depth and may measure environmental conditions such as water temperature; such measurements may be communicated back to the operator using a telemetry system.

A marine vessel comprising a command module, first and second buoyant tubular foils, and first and second struts for connecting the first and second buoyant tubular foils to the command module, respectively, wherein the first and second buoyant tubular foils provide substantially all buoyancy required for the marine vessel, and wherein the marine vessel further comprises first and second engines enclosed within the first and second buoyant tubular foils, respectively, and first and second propulsion units connected to the first and second engines, respectively, for moving the marine vessel through water, and means for reducing drag on the vessel as the vessel moves through water.

A marine vessel comprising a command module, first and second buoyant tubular foils, and first and second struts for connecting the first and second buoyant tubular foils to the command module, respectively, wherein the first and second buoyant tubular foils provide substantially all buoyancy required for the marine vessel, and wherein the marine vessel further comprises first and second engines enclosed within the first and second buoyant tubular foils, respectively, and first and second propulsion units connected to the first and second engines, respectively, for moving the marine vessel through water, and means for reducing drag on the vessel as the vessel moves through water.

The present disclosure provides a vessel, thrust of which is less likely to be lost. A vessel includes a hull having a vessel bottom, and a propulsion device. The propulsion device has a propeller that can rotate about a propeller shaft penetrating a shaft hole in the vessel bottom, and generates thrust for sailing the hull by rotation of the propeller. The hull has the groove section, which is long in the front-rear direction, around the propeller in the vessel bottom. The shaft hole is arranged in the groove section.

The present disclosure provides a vessel, thrust of which is less likely to be lost. A vessel includes a hull having a vessel bottom, and a propulsion device. The propulsion device has a propeller that can rotate about a propeller shaft penetrating a shaft hole in the vessel bottom, and generates thrust for sailing the hull by rotation of the propeller. The hull has the groove section, which is long in the front-rear direction, around the propeller in the vessel bottom. The shaft hole is arranged in the groove section.

This propeller propulsion apparatus for a ship includes a first propeller, a second propeller disposed coaxially with the first propeller and rotating in a direction opposite to the first propeller, a first electric motor configured to drive the first propeller, a second electric motor configured to drive the second propeller, a control unit configured to control each of the first electric motor and the second electric motor, and a memory unit configured to store a combination of rotational frequencies of the first propeller and the second propeller at each vessel speed where total power consumption of the first electric motor and the second electric motor is an optimum value, and the control unit controls the first electric motor and the second electric motor on the basis of the data of the memory unit such that the total power consumption at each vessel speed is the optimum value during an operation of a ship.

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 watercraft propulsion system includes a bow thruster to generate a lateral propulsive force, a propulsion device on a stern of a hull and having a variable steering angle, and a controller configured or programmed to control the bow thruster and the propulsion device to perform a fixed point holding control to maintain a position and an azimuth of the hull. The fixed point holding control includes a translation mode in which the hull position is maintained by controlling the propulsive force of the propulsion device with the steering angle set to a translation mode steering angle and the hull azimuth is adjusted by controlling the propulsive force of the bow thruster, and a bow turning mode in which the hull azimuth is adjusted by controlling the propulsive forces of the bow thruster and the propulsion device with the steering angle set to a bow turning mode steering angle.

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.