I guess you're asking for a quick history of the Sub Force, following W.W.II.
Immediately after the war, the world, once again (Remember W.W.I?) assumed that this was the war that would end all wars. So the politicians (never known for their foresight or deep thinking) decided that there was no need for a large Navy, never mind a large sub force. The majority of the Boats went into "Mothballs", at New London, and other ports. But the Navy had kept a few to play with.
AND, they'd gotten a couple of Type XXIs, from Germany.
Their reaction to these Boats was, "WOW !! I want some of those."
Then came the "Cold War". What a surprise, there were still tyrants and crazy people in the world.
The people woke up, kicked the politicians out of their "Dream World" and money was allocated for weapons. Now the Navy could have their Type XXI boats, American style. These would become the "Tang" Class.
But it takes time the design a new Submarine, from the ground up. What to do?
Well, we've got all these fleet boats, why not modernize and streamline them? And so was born the "Greater Underwater Propulsion Power" (GUPP) program. US Submarine sailors, long known for their respectful, hard nosed attitude towards all things military, called the resulting subs "Guppys".
Note: Jim Christley did a write up of the GUPP program in his "United States Naval Submarine Force Information Book". They were published by Graphic Enterprises of Marblehead, Ma. And are only slightly easier to find than copies of the Gutenberg Bible.
All three Classes of Fleet Boat (Gato, Balao & Tench) were use in the GUPP program, with many variations. The final, and predominant, version had enlarged batteries, and streamlined bow, superstructure and fairwater. There were three, main types, of fairwater, EB (Electric Boat) Sail, Portsmouth Sail and North Atlantic (or Glass) sail.
Did it extend their lives? Well the last of the Guppies went out in '73. You be the judge.
As for the Tangs, they weren't begun until 49 and the last one, USS Gudgeon (SS-567), was sold to Turkey in '87. USS Trout was decommissioned in '78 and last seen in Key West, in 2000, being used as a sonar target. All had decommissioned by 1980.
The last US diesel-electric sub built was USS Blueback (SS-581), Commissioned in 1959, decommissioned in 1990. She was the last US Diesel Boat in service.
If anyone has more question, drop me a line, I'll give you anything I have.
DBF !! Mike K