Favorite scenes: When John Ritter's love interest accidentally falls overboard, he jumps in after her. A hilarious, unexpected turn of events to be sure; but also interesting in that the production actually filmed stunt doubles going overboard, on location, from the Pacific Princess (probably while docked in port, though). It was this extra step to make the production more realistic ... from soundstage to "on location" ... that makes the sequence really pop.
Also, Sherman Hemsley and LaWanda Page (a bickering husband and wife) who get into an argument on one of the ship's elevators. He wanted to go up, she wanted to go down. Both Hemsley and Page were in classic form. Every time one of them made a point in the argument, the corresponding elevator button was pushed, resulting in an electrical short circuit and a stalled elevator. Hi-jinx ensue as they try to escape, and then make up.