Historical Procurement Assumptions
Two ships for each Carrier Battle Group (12 CVBGs x 2 = 24 ships)
One ship for each Surface Action Group (3 SAGs x 1 = 3 ships)
Total Procurement: 27 ships.
U.S. SLBM Procurement and Deployment
The reason the U.S. Navy wanted forty-five SSBNs in the Sixties was because they would break down nicely and provide a neat structure of five squadrons containing nine submarines each.
From Polaris to Trident: The Development of US Fleet Ballistic Missile Technology by Graham Spinardi