The Marietta Dal was a 7500 tonne liberty ship built in the USA in 1944 and is one of the most interesting shipwrecks off Brisbane. On May 15 1950, the 140 metre long ship was carrying a cargo of sulphur, oil, tractors and other general cargo when it ran aground on Smith Rock. Any hopes of salvaging the ship and cargo were quickly abandoned when the vessel broke in two.
Completely broken up, the remains of the Marietta Dal are now found in 10 metres to 18 metres and make for a fascinating dive. Scattered over a wide area of Smith Rock the main section of wreckage contains a twisted pile of plates, beams and the long prop shaft. However, the most interesting part of the wreck is the cargo of tractors, which look like small tanks with their caterpillar tracks. Even without the remains of the ship this is a wonderful dive as there are ledges, caves and gutters packed with marine life.
Smith’s Rock has three pinnacles the highest rises to about 6m below the surface; their jagged granite beauty belies their treachery to the shipping fraternity. Not as pretty as Flinders Reef but it has a rugged honeycombed terrain and plenty of structure that attracts a profusion of fish. With a maximum depth of around 20m the most interesting features sit around 15m. Good visibility will reveal large schools of batfish and butter bream and a large range of coral species like cod, angelfish, beaked coralfish, clownfish, and damsels. If you like the big stuff then wobbegong sharks, turtles and spotted rays frequent the area. And of course during the migration season you will hear the whale song.