Murder on the QE2 by Jessica Fletcher

Bestselling mystery writer and amateur sleuth Jessica Fletcher is invited to travel to London on the grand dame of ocean liners, the "Queen Elizabeth II", as one of seven guest lecturers. She's done it before in these novels - speak on mystery writing. This time she has also written a short mystery play, to be performed one act-a-day during the crossing. The other lecturers will make guest appearances. Sounds like fun.

During the evening of the very day they set sail, a fellow speaker is found brutally murdered. She was going to play one of the characters in Jessica's mystery play but she died even before the first act! Now Jessica has just four days at sea to find the killer before she finds more of her colleagues, or even herself, dead in the water!

Librarian's note #1: the first 15 books in the current Jessica Fletcher / Donald Bain "Murder She Wrote" series are #1, Gin & Daggers (1989) with a 2nd edition in (2000); #2, Manhattans & Murder (1994); #3, Rum & Razors (1995); #4, Brandy & Bullets (1995); #5, Martinis & Mayhem (1995); #6, A Deadly Judgment (1996); #7, A Palette for Murder (1996); #8, The Highland Fling Murders (1997); #9, Murder on the QE2 (1997); #10, Murder in Moscow (1998); #11, A Little Yuletide Murder (1998); #12, Murder at the Powderhorn Ranch (1999); #13, Knock 'Em Dead (1999); #14, Trick or Treachery (2000); and #15, Blood on the Vine (2001).

Librarian's note #2: there is an earlier MSW series by James Anderson and David Deutsch. Novelizations of TV episodes. This original series has 4 volumes: #1, The Murder of Sherlock Holmes (1985); #2, Hooray for Homicide (1985); #3, Lovers and Other Killers (1986); and #4, Murder in Two Acts (1986).