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
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
138
USN about 250.
1. Ballistic submarines 2. Attack submarines
52 US submarines were lost in WW2. This was about 1 in every 5 submarines that the US had in WW2
the military and navy use it for war and combat. Many submarines are made for launching missels and taking down ships and other subs.
Females have been riding submarines for many years, but primarily only as riders (e.g., Contractors, Intelligence analysts, etc.). Up until recently, females serving aboard U.S. Navy submarines was restricted - however, with recent changes in policy, female officers will begin serving aboard FBM submarines within the next few years. Most navies with nuclear submarines (e.g., Royal Navy) don't allow women to serve aboard submarines due to the unique health risks that women are exposed to if serving aboard for long periods of time.