A method for converting a vehicle by exchanging its drive unit from an internal-combustion drive principle to an electrically operated drivetrain, whereby the drive unit with at least one electrically operated motor is provided as a replacement unit, whereby the replacement unit (i) is spatially compatible with the available installation space of the removed drive unit with an internal-combustion engine, (ii) is mechanically compatible with the interfaces and (iii) behaves functionally identically at all interfaces. The invention follows the form-fit-function idea and thus enables extremely rapid market access for converted vehicles because they can continue to use existing parts approvals for the largest possible part of their components, thus making new approval tests unnecessary as far as possible.

A hydrofoil vehicle comprises a frame and at least one foil. The vehicle comprises a moveable control surface configured to control a pitch of the vehicle, in use. A locking mechanism is provided for restricting movement of the control surface when the vehicle is not foiling, for example during launching. In examples, the locking mechanism activates automatically when the hydrofoil vehicle is not foiling. In examples, the vehicle is human powered.

A marine propulsion device includes a drive shaft, a propeller shaft, and a lower case that houses the propeller shaft. In the marine propulsion device, a power generator generates power using a torque of the drive shaft or the propeller shaft, and the generated power is supplied to an electric actuator to drive a driven unit through a first power line, wherein the electric actuator is controlled by a controller. At least a portion of the driven unit, at least a portion of the electric actuator, at least a portion of the power generator, and the first power line are located in the lower case.

A marine propulsion device includes a drive shaft, a propeller shaft, and a lower case that houses the propeller shaft. In the marine propulsion device, a power generator generates power using a torque of the drive shaft or the propeller shaft, and the generated power is supplied to an electric actuator to drive a driven unit through a first power line, wherein the electric actuator is controlled by a controller. At least a portion of the driven unit, at least a portion of the electric actuator, at least a portion of the power generator, and the first power line are located in the lower case.

A marine propulsion device includes: a propeller; a first power source for rotating the propeller, a second power source for rotating the propeller; a propeller shaft provided with the propeller; a first drive shaft connected to the first power source; a second drive shaft connected to the second power source; a transmission shaft connected to the propeller shaft; and a dog clutch that switches a connection mode of the first drive shaft, the second drive shaft, and the transmission shaft between at least two of: a first mode in which the first drive shaft and the transmission shaft are connected to each other; a second mode in which the second drive shaft and the transmission shaft are connected to each other; and a third mode in which both the first drive shaft and the second drive shaft are connected to the transmission shaft.

A marine propulsion device includes: a propeller; a first power source for rotating the propeller, a second power source for rotating the propeller; a propeller shaft provided with the propeller; a first drive shaft connected to the first power source; a second drive shaft connected to the second power source; a transmission shaft connected to the propeller shaft; and a dog clutch that switches a connection mode of the first drive shaft, the second drive shaft, and the transmission shaft between at least two of: a first mode in which the first drive shaft and the transmission shaft are connected to each other; a second mode in which the second drive shaft and the transmission shaft are connected to each other; and a third mode in which both the first drive shaft and the second drive shaft are connected to the transmission shaft.