A part of the US Strategy concerning the Battle of the Atlantic must include a plan to Search & Destroy the German U-Boats.
A German U-Boat unit costs 4 IPC.
A US Battleship unit - or even a Super Heavy Battleship unit (supported by a Destroyer unit) - can take damage hits in a Naval Battle against German U-Boat units.
A Damage Hit on a Battleship unit can be repaired each at a cost of 3 IPC.
With sufficient US Battleship units - supported by a limited number of Destroyer units - and massive support by Air units - the USA is able to counter any threat from German U-Boat units - and win the Battle of the Atlantic economically.
This is the most popular US strategy concerning the battle against German U-Boat units in the Atlantic.