Who Killed Davidian Jonas?

A shipping tycoon's corpse is discovered draped over his yacht's anchor when it is hoisted out of the water. The tycoon's intended merger would ruin several of the guests on his current cruise. A large earring is a major clue - did it belong to the victim's brother (a gypsy king), or the maharanee, or perhaps to the ship's sexy radio operator? Or was the killer the rival shipping magnate, the boozy hanger-on, or his ever-so-pleasant PR man? When Burke finally realizes the importance of whose stateroom was where and how much alcohol was drunk on the night of the fatal party, he knows who the killer is.