Depending on the budget situation, typically between 3-5 years.
During WW2 the US Navy built 126 submarines.
at present 16 of the submarines are in duty. 20 submarines are planned to submurge into sea in the forthcoming years.
At the beginning of 1917 the German navy had 111 submarines. This was a large increase from 1916 when they had only 68.
75
In the later years of the Cold War, under President Ronald Reagan, the U.S. Navy commissioned and built the Los Angeles-class submarines and designed and manufactured the Tomahawk cruise missile. Reagan's administration emphasized military buildup and modernization as part of its overall defense strategy. The Los Angeles-class submarines were pivotal for stealth and deterrence, while the Tomahawk missile enhanced the Navy's strike capabilities.
The US Navy currently has 14 active duty Trident (Ohio Class) Ballistic Missile Submarines. They are scheduled for replacement beginning in 2028.
The PLA navy has more than 225,000 personnel and is thought to have as many as 70 submarines, 10 of them nuclear-powered
USN about 250.
138
52 US submarines were lost in WW2. This was about 1 in every 5 submarines that the US had in WW2
1. Ballistic submarines 2. Attack submarines
the military and navy use it for war and combat. Many submarines are made for launching missels and taking down ships and other subs.