A Deep Submergence Rescue Vehicle or DSRV is a marine vessel used for rescuing crew from downed submarines and other clandestine missions. These are specialized vessels that require highly skilled professionals to operate these vessels and successfully carry out complex rescue missions. There are a number of countries that operate DSRVs with different designations for these vessels operated by these countries. The general designation for these vessels are underwater submarine rescue vehicles and the importance of these vehicles for rescuing of submarine crew from a damaged submarine cannot be overstated. During the Second World War a lot of experienced submarine crew from various countries were lost due to hostilities between countries and accidents occurred onboard submarines. During the Cold war, many sailors onboard submarines being tested or during deployment were lost as the submarines lost power and could not emerge to the surface due to explosions onboard the submarines. These casualties could have been prevented if the DSRVs were fully operational at the time of these incidents. These incidents however gave impetus to the development of the DSRV technology to reduce loss of life to crew operating submarines and other submersibles.
The Deep Submergence Rescue Vehicle is designed to rescue up to 24 people at a time at depths up to 600m ( 1,0969ft) with a maximum operating depth of 1500m (4,921ft). Power is provided by two large batteries located fore and aft of the vessel. The DSRV uses mercury in a completely sealed system that allows it to match any angle (up to 45 degrees) in both pitch and roll so as to attach itself to the damaged submarine that may be resting at the seabed at an angle. The DSRV is usually transported by the large C-5 Galaxy air force transport plane to the designated country. It is then loaded unto the mother submarine which transports the DSRV to the rescue site. Several trips are made by the DSRV to the location of the damaged submarine to rescue the crew and bring them to the surface. The rescued crew are taken to the mother submarine or any surface support ship present in the vicinity of the rescue site. The interior of the DSRV consist of three spheres, the forward sphere which is the control sphere where the pilot and copilot of the vessel operate it. The two aft spheres known as the Mid sphere and Aft sphere are used to seat the rescuees or to install equipment for additional operations. Manoeuvering is achieved using four thrusters and one main propeller. Other countries carry their submarine rescue vehicles in large mother ships directly to the rescue site where the rescue vehicle is lowered from the mother ship into the sea floor to initiate the rescue of crew from the damaged submarine.
Italy, Sweden, the United Kingdom, France, Japan, Korea and Singapore are all believed to operate submarine rescue vehicles lowered from the mother ships into the sea for submarine rescue operations.