A method for controlling the hybrid drive system of a water craft, comprising a combustion engine (1), an electric engine/generator (2), a drive train (5) having a propeller (7) and a storage battery (3), a control unit (8) and a clutch (4). In order to increase efficiency, during travel in the upper power range the electric engine (2) is additionally operated as a generator, and during travel in the middle and lower power ranges the electric engine (2) is operated with current from a storage battery (3). The drive train is designed so that the characteristic (20) thereof lies by a defined charging capacity below the point of minimum specific fuel consumption (e.g. 25), or is steeper than the characteristic (16) of a conventional construction.

Vehicles are disclosed which have a lower center of gravity than existing all-terrain, amphibious, and unmanned ground vehicles due to the location of propulsion units and other vehicle components inside the wheels of the vehicle. The vehicles can climb over large obstacles yet are also able to corner at high speeds. The vehicles can be configured for direct manual operation or operation by remote control, and can also be configured for a wide variety of missions.

A modular bicycle and board apparatus having a buoyant board, a front wheel, a rear wheel and handlebars mountable and usable in a first configuration as a bicycle in which the buoyant board is the bicycle's frame and in a second configuration as a surfboard by changing the orientation of the front wheel and handlebars with 90 degrees with respect to the buoyant board, the surfboard being steerable from the handlebars.

Vehicles are disclosed which have a lower center of gravity than existing all-terrain, amphibious, and unmanned ground vehicles due to the location of propulsion units and other vehicle components inside the wheels of the vehicle. The vehicles can climb over large obstacles yet are also able to corner at high speeds. The vehicles can be configured for direct manual operation or operation by remote control, and can also be configured for a wide variety of missions.

A fuel overfill recovery apparatus for recovering fuel from a watercraft's overflowing fuel tank includes a container with a first wall and a second wall. A reservoir is defined between the first and second walls. An aperture extends through the first wall, and a connector is provided for connecting the container to the watercraft such that a fuel tank of the watercraft is in fluid communication via the aperture. Vents extend into the second wall so that gases may freely flow out of the reservoir without taking up space that may be used for overflow fuel. A spout is provided at the bottom of the container to selectively release fuel from the reservoir.