Could an army ambush a fleet inside a port?

Could a camouflaged land army lure a fleet into a deep inland port and destroy it?

Theoretically, but suspicion, reconnaissance and sailors' local contacts would make the trap difficult.

An army could attack ships after luring them into harbour and approaching while much of the crew slept. The first difficulty is why the fleet would enter. An enemy port would invite suspicion, and an uncertain harbour might receive only one ship or reconnaissance boats while the fleet stayed outside. Port size also limits which ships can enter. In the Age of Sail, wartime crews often included men with merchant-service experience of the port. Those sailors might notice unusual conditions or receive warnings from local acquaintances.