When they were built in 1917, the J Class Submarines were the fastest in the world. They boasted a surface speed of 19 knots, and a submerged speed of 10 knots. They were 85m long, with a displacement of 1260 tons, and carried a crew of 44. Seven vessels were built. The J6 was lost during W.W.1.
The remaining 6 submarines were a gift from the British Government to the Royal Australian Navy in 1919. However due to their high operating costs, and subsequent budget cuts, they saw little service. In 1924 four vessels, designated as JI, J2, J4, and J5 were sold to a salvage company which stripped them of valuable fittings. The submarines were then scuttled outside the Heads in 1926.
Some confusion exists among different organizations as to the naming of the submarines. We have referred to them by the names they are commonly known. A dive on any of the four scuttled submarines is both challenging and rewarding. They play host to a huge variety of marine life, and are sufficiently large to require more than one visit if the diver is to fully explore them. Divers should approach them with caution, however, owing to their depth.
Penetration inside these vessels should only be attempted by experienced and competent buddy pairs, who are both properly equipped for this type of diving. The submarines offer spectacular diving in good conditions, and many interstate divers visit our region specifically to dive them. For competent and experienced divers, they are highly recommended.