What is Underwater Propulsion?
In order to increase the range underwater of scuba and rebreather divers, they use an item of diving equipment called underwater propulsion vehicle, also known as underwater scooter or diver propulsion vehicle or DPV.
The definition of range covers three areas, and these are the restricted amount of breathing gas being carried, the rate of consumption of that breathing gas under exertion, and the time limit as regulated on the dive tables to prevent decompression sickness of divers.
A DPV has several structures, and these are a pressure-resistant watertight casing that contains a battery-operated electric motor, which drives a propeller. The design is made in such a way that the diver is not harmed by the propeller, the diving equipment, or the marine life, and that the vehicle cannot be accidentally turned on or run away from the diver, and it has to remain neutrally buoyant while use in underwater.
The usual uses of underwater propulsion vehicle are for cave diving and technical diving, where deep diving needs the help to move big equipment and making divers use better of the limited underwater time based on the decompression requirements. DPV accessories, if mounted on the accessory board of the DPV can make the vehicle more useful underwater. The accessories that can be mounted on to the DPV are compasses, cameras, lobster sticks and even spear guns.
Military applications also use a DPV to deliver combat divers and their equipment at speeds and distances that seem impossible.
Know that the use of DPV is more than simple swimming, but requires depth control, buoyancy adjustment, monitoring of breathing gas, and navigation.
There are various kinds of DPV, and the most common type tows the diver who holds onto the handles on the bow or stern. With the diver placed parallel to and above the propeller wash, this tow-behind scooter is at its most efficient operation.
The next kind of DPV is termed manned torpedoes, shaped like a fish, where the one or more divers can sit typically astride on it or in hollows inside.
The next kind of DPV is called a subskimmer which is described as a rigid-hulled inflatable boat, powered by a petrol engine when on the surface, and when being submerged, the petrol engine is sealed and the vehicle runs on battery-electric thrusters being attached on a steerable cross arm.
As DPVs get bigger, they now turn into the big vehicle called the submarines. There are also small submarines called wet subs, where the pilot’s seat is flooded that then requires the diver to wear diving gear.