London, United Kingdom — The Special Boat Service (SBS) will be getting new mini-subs from the United States.

After the budget announcements for the next year, the British government approved the purchase of three MK 11 Shallow Water Combat Submersibles (SWCS) to replace the ageing MK VIII Mod 1 Swimmer Delivery Vehicle (SDV). The SWCS are manned mini-submarines that can hold up to six operators and their equipment. They can be launched and recovered by both surface warships and submarines that are fitted with the necessary dry dock shelter (DDS) apparatus. SWCS can also be attached underneath a helicopter.

SDVs are used to clandestinely transport operators to their target. The U.S Navy SEALs also use the SWCS. They can remain underwater for many hours and can avoid most detection systems. The use of midget subs and SDVs goes back many decades. During the Second World War, Italian frogmen utilised SDVs to successfully attack the British fleet in Alexandria. The British, for their part, utilised midget submarines to seriously damage the fearsome German battleship Tirpitz.

Whereas the Navy SEALs have a specific unit tasked with operating SDVs — the SEAL Delivery Vehicle Team — the SBS has only one dedicated squadron. Z Squadron specializes in underwater insertion and attack operations using the SDVs.