Us capital warships

[CCIP]

You'll have better luck looking for them at sea than in harbors, on convoy escort (particularly in arctic waters), as well as a few specific operations (like D-Day). You might have some luck with ships transiting along the US coast, as many were built and repaired in eastern shipyards (most notably New York and Philadelphia), but once there they'd be spending most of their time docked. Otherwise the bases aren't the smartest thing to go for. Norfolk is probably a decent bet, being the main base for the Atlantic fleet, but I'm not sure what there is in the game.