What is an Underwater Propulsion Vehicle
Scuba and rebreather divers are using an underwater propulsion vehicle, or called diver propulsion vehicle (DPV) or underwater scooter, as one of their diving equipment items that increases their range underwater.
The meaning of range can be explained in three situations, and these are the restricted quantity of breathing gas that can be carried, the rate of breathing gas consumed under exertion, and the time limits stated by the dive tables in order to avoid decompression sickness of divers.
A DPV has its basic features of a watertight casing that is pressure-resistant that contains an electric motor being battery powered, that leads to driving a propeller. When the design was made for this vehicle, it was in such a way that the vehicle should not harm the diver, diving equipment, or marine life, and that it cannot be accidentally started nor will run away from the diver, and that the vehicle has to remain neutrally buoyant while it is used 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. To make a DPV more useful, some accessories can also be mounted to the DPV accessory board. These accessories are dive gears like 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 several types of DPV, and the most common type is that which tows the diver while holding onto the handles on the stern or bow. This so called tow-behind scooters are most efficient with the diver placed parallel to and above the propeller wash.
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.
Described as a submersible rigid-hulled inflatable boat, this another kind of DPV is called a subskimmer that is powered by a petrol engine if on the surface, and when submerged, the petrol engine is sealed, and the vehicle then runs on battery-electric thrusters that are located ona a cross-arm that is steerable.
By now, you would have realized that as DPVs get larger, they gradually become 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.