The Lesser Antilles Case: A Lt. Valcour Mystery, by Rufus King (epub/Kindle/pdf)
Disaster at sea! When the yacht "Helsinor" strikes a reef in the Lesser Antilles, the passengers take to a lifeboat. Upon their return to the United States, accusations fly. Did one of the survivors drug the others and pitch the millionaire owner of the yacht, Lawrence Thacker, into shark-infested waters? Lt. Valcour begins an informal investigation. When one of the heirs to the Thacker millions is poisoned, Valcour's investigation becomes official. The only thing to do is gather the survivors aboard the "Helsinor II" and return to the scene of the wreck...