Final resting place? Deck chair

Sheila Mackey has a secret. To the world, she’s author of a blockbuster book. Her wily great-aunt, the actual author, orchestrated this mutually beneficial masquerade. Now the aunt’s retiring and Sheila must draft Act Two of her own life. This cruise is supposed to be the perfect time to do that.
Crossing the Atlantic on the Diversion, Sheila finds a dead body on deck.
She realizes she knows a whole lot more about the interactions of the victim and suspects than the ship’s officials do. She’s drawn into sleuthing, but finds herself hampered by a well-meaning but overprotective would-be Dr. Watson.

This murder mystery with humor is the first book in the Secret Sleuth series. In later books, amateur sleuth Sheila returns to dry land in the Midwest, where mysteries abound in her new home in small-town Kentucky.