Diver Propulsion Vehicle

Diver propulsion vehicle

Recreational diver using a lightweight diver propulsion vehicle
Acronym	DPV
Other names	Diver propulsion device, Underwater scooter
Uses	Reduce diver effort and increase speed and range during a dive

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.

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.

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. There are also DPV accessories that can be mounted to a DPV accessory board to make your DPV more useful. Dive gear such as compasses, cameras, lobster sticks and even spearguns can also be mounted to DPVs.

Military applications include delivery of combat divers and their equipment over distances or at speeds that would be otherwise impracticable.

DPV operation requires more situational awareness than simply swimming and operating a DPV requires simultaneous depth control, buoyancy adjustment, monitoring of breathing gas, and navigation. Buoyancy control is vital for diver safety: The DPV has the capacity to compensate for poor buoyancy control while moving, but on stopping the diver may be dangerously positively or negatively buoyant if adjustments were not made to suit the changes in depth while moving. If the diver does not control the DPV properly, a rapid ascent or descent under power can result in barotrauma. Many forms of smaller marine life are very well camouflaged or hide well and are only seen by divers who move very slowly and look carefully. The fast movement can frighten some fish into hiding or swimming away, and since the diver is not kicking for propulsion, they will generally get colder due to lower physical activity and increased water flow.