On a cruise, you see the Pilot Boat at every port you stop in. The Pilot boards the cruise ship before it enters the port to help guide it in. The Pilot is the expert on all the hazards in a port and keeps the cruise ship captain out of trouble. The use of a Pilot is pretty much mandated by maritime law. As the cruise ship leaves the port, the Pilot jumps from it to his little boat while both ships are in motion. He waves good-bye to all the passengers on deck and then the two ships trade a few blows on the horn before separating. Fun to watch.
Even though the cruise ship is large, it can turn on a dime. As a matter of fact, it can stay in one spot and spin using thrusters built into the bow and stern of the ship. You can see the turbulence in the water as the thruster operates.