I like to do something similar once marines come on the scene. I'll load up 1-3 transports with them, covered by enough escorts to remove cultural defense and a carrier or two for softening up any defenders present. This strike force will then terrorize the enemy coast, but deliberately never take a city until the enemy's army is broken. My marines destroy all the units but one, and as long as the AI has available reserves, he'll pour them into the city for me to repeat the drill the next turn. This works great with SEALs due to their free march promotion. Once his counterattack capability is utterly destroyed, I'll take a beachhead city and pour in my land forces through it.My favorite naval warfare tactic is to get astronomy or combustion and build a invasion stack with 10 or so galleons/transports + support from destroyers... then use them to invade and hop between your target's coastal cities without penetrating so much on land... the AI is good at predicting how many defensive forces to pile up when they see your stack approaching on land... but navies move so quickly (especially transports), they have a hard time compensating. I can get capitulations quickly like this on prince.