![]() 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. High speed travel in confined spaces, or limited visibility can increase the risk of impact with the surroundings at speeds where injury and damage are more likely. If the diver does not control the DPV properly, a rapid ascent or descent under power can result in barotrauma or decompression sickness. Buoyancy control is vital for diver safety: The DPV has the capacity to dynamically compensate for poor buoyancy control by thrust vectoring while moving, but on stopping the diver may turn out to be dangerously positively or negatively buoyant if adjustments were not made to suit the changes in depth while moving. Operating a DPV requires simultaneous depth control, buoyancy adjustment, monitoring of breathing gas, and navigation. Limitations ĭPV operation requires greater situational awareness than simply swimming, as some changes can happen much faster. ![]() Use of a DPV on deep dives can reduce the risk of hypercapnia from overexertion and high breathing rate. ![]() There are accessories that can be mounted to a DPV to make it more useful, such as lights, compasses, and video cameras. Military applications include delivery of combat divers and their equipment over distances or at speeds that would be otherwise impracticable. 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. 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 approximately neutrally buoyant while in use underwater.ĭPVs are useful for extending the range of an autonomous diver that is otherwise restricted by the amount of breathing gas that can be carried, the rate at which that breathing gas is consumed, which is increased by exertion and diver fatigue, and the time limits imposed by decompression obligation, which depend on the dive profile. The earliest recorded DPVs were used for military purposes during World War II and were based on torpedo technology and components.Ī DPV usually consists of a pressure-resistant watertight casing containing a battery-powered electric motor, which drives a propeller. DPVs have recreational, scientific and military applications.ĭPVs include a range of configurations from small, easily portable scooter units with a small range and low speed, to faired or enclosed units capable of carrying several divers longer distances at higher speeds. Time limits imposed on the diver by decompression requirements may also limit safe range in practice. Range is restricted by the amount of breathing gas that can be carried, the rate at which that breathing gas is consumed, and the battery power of the DPV. Two divers scootering with heavy duty DPVsĪ diver propulsion vehicle ( DPV), also known as an underwater propulsion vehicle, sea scooter, underwater scooter, or swimmer delivery vehicle ( SDV) by armed forces, is an item of diving equipment used by scuba divers to increase range underwater.
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