A certain piece of Ronald Reagan's military buildup was the promise of a 600 ship navy. This was an increase from about 530 ships at the end of Carter's administration. This went down further to 521 ships in 1981 before reaching a peak of 594 ships in 1987.
The world war 2 peak was 6768 ships. There were about 2500 Amphibious landing ships to achieve actions like the D-Day invasion. There was a peak of 833 major surface ships. 377 Destroyers. 361 Frigates. 28 aircraft carriers. 23 Battleships. 232 submarines.
From 1950 to 1953 there was a renewed buildup for the Korean war that reached a peak of 1122 ships. 20 aircraft carriers. 326 major surface ships. 108 submarines
From 2005-2015 there have been 271 to 289 ships.
Military Analyst Jerry Hendrix is happy and believes most of the US Navy's problems will be solved with more ships and budget
The last time the US Navy had 350 ships in its inventory was in early 1998, at which time it had twelve carriers, 30 cruisers, 53 destroyers, 40 frigates and 70 fast attack submarines. Five years later the Navy crashed through the 300 ship mark on its way to the 272 ships it has today, which includes 10 carriers, 22 cruisers, 62 destroyers, no frigates and 54 fast attack submarines. Much of this decline has been driven by the fact that individual ship costs have gone up owing to new advanced technologies while the Navy’s ship construction spending account has remained flat, driving the number of ships that can be purchased downward.
The Navy’s budget today should be around $190 billion per year according to the last threat-based budget proposed by then Secretary of Defense Robert Gates in 2011, but instead it struggles with a $155 billion budget imposed by the administration he left in disappointment.
Defending the carrier in the new anti-access / area denial environments that the Navy increasingly found itself in around the world. A 272 ship Navy simply does not have enough cruisers and destroyers to surround and protect each of the carriers it deploys, but a 350 ship Navy can generate enough platforms to protect a twelve carrier strike force. However, the key vulnerability of our carriers to attack is driven not by the threat or even the ships that surround them, but rather it is a product of the present composition of the carrier’s air wing, which forces these large capital vessels to operate ahistorically close to land. Changing the composition of the carrier’s embarked air wing is the key improvement the Navy can make in the near term to guarantee the success of its carrier strike groups in the future.
SOURCES- Wikipedia, US Navy history, National Interest