The J-Class submarines: J1, J2, J3, J4, J5, J7 were all built between 1915-1917. The overall length was 274.7ft, beam 23ft and draught 14ft giving a displacement weight of 1210 tons surfaced. Their wartime complement was 5 officers and 40 men. The six British built submarines were transferred to the Royal Australian Navy on 25 March 1919. They had served for a short time with the Royal Navy’s 11th Submarine Flotilla, and although they proved to be the fastest submarines of their time, they were unreliable. So they ended up in Australia! The six submarines departed Portsmouth on 9 April 1919, arriving in Sydney on 10 July where they underwent a very necessary refit. By May 1922 all six submarines had been decommissioned and now we are fortunate to be able to dive some of them in Port Phillip Bay.  Contact us on 03 9579 2600 to find out more and book your place on the boat.