In 1940, during the early days of the Second World War, German U-boats patrolled the North Atlantic, successfully attacking merchant ships steaming to and from England. The British Admiralty needed a warship to escort the convoys across the Atlantic and it had to be very proficient in anti-submarine warfare. So, the River Class frigate was born. In total, 151 frigates were built, 133 during World War 2, mainly in Great Britain (57) and Canada (70). Eight were built in Australian shipyards. Diamantina was built by Walkers in Maryborough.

Diamantina served in the Pacific Campaign in 1945, operating in the Solomon Sea, conducting escort duties and supporting the Allied operations ashore on Bougainville. It’s believed that she was the last Australian naval vessel to bombard enemy positions in 1945.

She also took the surrenders of the Japanese garrisons of Nauru and Ocean Islands on her quarterdeck. The surrender of Ocean Island was the last surrender to be signed at the end of World War 2.

Following service in the Pacific Campaign, Diamantina was placed in reserve in August, 1946. She rested in Williamstown, Victoria until 1959, when she became the first of two warships dedicated by the Australian Navy to oceanographic research. Diamantina did some of her most important work in the Indian Ocean. In 1960, while working off Cape Leeuwin (the most south-westerly point of mainland Australia), she charted what was then the greatest depth ever recorded on the Indian Ocean’s floor, dropping to over 4 000 fathoms or 7.3 km below the surface. It was named the Diamantina Fracture Zone.

Diamantina first commissioned in April, 1945. She was 91.82 m (301 feet 4 inches) long and 11.13 m (36 feet 6 inches) wide. She was powered by two boilers supplying steam to two 4 cylinder triple expansion engines to two propellers. Top speed was about 19 knots (35 km per hour). She carried a crew of nine officers and up to 150 ratings. All officers were reservists.

From the bow of the ship, we have the foredeck with the anchor windlass. This is followed by the superstructure, containing cabins, the wireless office and galley, with the wheelhouse above and the bridge at the top. Also, we see the forward 4″ gun with a Bofors 40mm anti-aircraft gun on the shelter behind.

In the middle of the ship is the funnel and the ship’s boats. At the after end is the aft 4″ gun with its gun shelter. At the stern is the aft deck, with two more 40mm Bofors anti-aircraft guns and Diamantina’s anti-submarine weapons; the depth charge throwers and the depth charge rails.