Passage of the Tangmar 1960 (ep1-10) Australian Serial 

The cargo ship Tangmar departs Sydney, destination Jamaica, with a small party of passengers, strangers who are to share the fortune of an inheritance.
Not all of them will survive the journey. Passage of the Tangmar is a riveting, adult mystery serial produced in Australia in 1960. Australian radio is on par with the British BBC productions - outstanding stories, impeccable acting and exceptional sound effects; Passage of the Tangmar is a superb example of that work.
The 52-episode program about the Tangmar and its cargo of death is unusual, first that it’s in a 15-minute serial format that is typically reserved for children’s shows and old-time radio soap operas. Second, unlike many children’s serials or soap operas, Passage of the Tangmar has a conclusion with a solution, a story that caters to mystery connoisseurs.