We have 42 active Los Angles class hunter-killer submarines

[HooptieWagon]

113. The number needed is fairly easy to estimate,

although there are some people whose agenda is to cease any military spending. There are 11 carrier task forces. They are currently operating with 2 sub escorts each. This is sufficient in peaceful waters, but should be 4 in possibly hostile waters... call it an average of 3, for 33 subs necessary for carrier task force missions. The Russians currently have 15 ballistic missle subs in service (3 Typhoons, 12 Deltas), The Chinese have 5 (1- 092 class, 4- 094 class). Each should have a tail, that adds another 20 attack subs. Maybe a dozen are needed for individual missions; sea patrol, blockade duty, or special ops. Perhaps about 10 would be out of service at any given time for repairs, overhaul, or training duty. So, my admittedly inexpert rough estimation shows a need for about 75 attack submarines. Obviously not all will be the newest classes, the most recently built LAs won't be retired for another 15+ years. And possibly the Navy can get by with a few less, but I think the current 52 is several boats too few.