While the U.S. Navy has developed larger mini-subs for SEAL commandoes (to go from a nuclear submarine to an enemy beach), they have given the British three of the older SDV (Swimmer Delivery Vehicles). Britain built an 9x9x40 foot pressurized enclosure that can quickly be mounted on the deck of a British nuclear submarine to house the SDVs and enable British SBS (the British naval commandos that the U.S. SEALs were based on) to easily go from a nuclear sub, several kilometers off shore, to a beach. The DSV looks like a torpedo, and is propelled by batteries. About a dozen men in scuba gear can hang onto a DSV as it is driven to shore, where the commandos swim the rest of the way in with their gear. The SBS got the DSVs in 1999, and it took over three years to build the enclosure for the nuclear subs. The enclosure, and the SBS commandoes, can be flown anywhere in the world where there is a British nuclear submarine to use it.