When arriving on a cruiseship and leaving same day. does that qualify for the 72 hour visa?

The premise for 72 hours free transit is that the passengers must fly into and fly out. So you are not ok for 72 hours free transit. However, you still needn't apply one if you stay less than 24 hours because you are still ok with 24 hours free transit. It hasn't any requirement on how you enter and exit mainland China.