The second largest expansion of the Base occurred during World War II, when it grew from 112 acres to . The Submarine Force leaped in size, and the Base accommodated thousands of men to serve the growing combat fleet. Immediately after World War II, the Submarine Force was significantly reduced and many submarines were sent into storage. Most of the World War II fleet was sold for scrap metal during the early 1960s. From 1930 to 1994, the most recognizable structure on the base was the Escape Training Tank. Generations of submariners learned to escape in up to of water using buoyant ascent, and were trained in the use of the Momsen lung or Steinke hood. In 2007, the Escape Training Tank was replaced by the Submarine Escape Trainer, which has two types of escape trunks in up to of water. The Steinke hood was replaced by the Submarine Escape Immersion Equipment in the 2000s. The New London Base is homeport to 16 attack submarines and full Navy base situated in Groton, Connecticut. The Base is also neighbor to the major submarine construction yard of General Dynamics' Electric Boat Division. All officer and enlisted submariners are stationed at Groton during their training, with the exception of nuclear trained Electronics Technicians (ETs), Electrician's Mates (EMs), and Machinist's Mates (MMs). Enlisted sailors attending sub school will first go through Basic Enlisted Sub School (BESS), an eight-week program that teaches the rigors of undersea life. BESS includes training in shoring, patching leaks and ruptured pipes, firefighting, and boat handling techniques. After BESS, sailors will either go to a boat or to follow-on schools. The main base occupies more than plus over of family housing. It also supports more than 70 tenant commands, including Naval Submarine School (NAVSUBSCOL), Naval Submarine Support Facility (NSSF), three Submarine Squadron staffs, and the housing and support facilities for more than 21,000 civilian workers, active-duty service members, and their families. On 13 May 2005, the Pentagon recommended that the base be closed. After review, the 2005 Base Realignment and Closure Commission voted on 24 August 2005 to strike New London from the list of possible closures, thus allowing the base to remain open.