Fenster

Fenster may refer to:

Scooter

Scooter may refer to:

Vehicles

Ground

Human or gravity powered

Motorized

Air

Water

Scooter (motorcycle)

A scooter or motor scooter is a motorcycle with step-through frame and a platform for the rider's feet. Elements of scooter design have been present in some of the earliest motorcycles, and motorcycles identifiable as scooters have been made from 1914 or earlier. Scooter development continued in Europe and the United States between the World Wars.

The global popularity of scooters dates from the post-World War II introductions of the Vespa and the Lambretta. These scooters were intended to provide low-power personal transportation (engines from 50 to 250 cc or 3.1 to 15.3 cu in). The original layout is still widely used in this application. Maxi-scooters, with engines from 250 to 850 cc (15 to 52 cu in) have been developed for Western markets.

Scooters are popular for personal transport, partly due to being cheap to buy, easy to operate and convenient to park and store. Licensing requirements for scooters are easier and cheaper than for cars in most parts of the world, and insurance is usually cheaper.

Diver propulsion vehicle

A diver propulsion vehicle (DPV, also known as an underwater propulsion vehicle or underwater scooter) is an item of diving equipment used by scuba and rebreather divers to increase range underwater. Range is restricted by the amount of breathing gas that can be carried, the rate at which that breathing gas is consumed under exertion, and the time limits imposed by the dive tables to avoid decompression sickness. DPVs can have military application.

Structure

A DPV usually consists of a pressure resistant watertight casing containing a battery-powered electric motor, which drives a propeller. The design must ensure that the propeller cannot harm the diver, diving equipment or marine life, the vehicle cannot be accidentally started or run away from the diver, and it remains neutrally buoyant while in use underwater.

Application

DPVs are useful for extending the range of a diver that is otherwise restricted by the amount of breathing gas that can be carried, the rate at which that breathing gas is consumed under exertion, diver fatigue, and the time limits imposed by the dive tables to avoid decompression sickness. Typical uses include cave diving and technical diving where the vehicles help move bulky equipment and make better use of the limited underwater time imposed by the decompression requirements of deep diving.