Cruise ships have 4 or 5 giant engines. Two of them run giant big generators

Last cruise ship I was on, an engineer at our table was explaining that cruise ships now are mostly diesel electric, much like a railroad locomotive. That means that all their diesel engines run generators, and then electric traction motors turn the propellers.

He said this allows the traction motors and propellers to be mounted on swivels. That makes the ship far more maneuverable. They can now dock without the need for tugboats.

A group of us asked for an engine tour (at the "pursers desk--the main hotel desk). After a day or so, we were declined in a formal note. Tours of the helm may still be possible if you ask. They do say after the problem with pirates some years ago, engine room tours are now rare. But kitchen tours and back stage tours are still available if you ask and some are even offered.