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J3 Swan Island Submarine

Wreck DiveWreck Dive | Boat access

Inside Port Phillip Wreck Dive Site

Diesel Electric Submarine | Max Depth: 8 metres (26 feet)

J3 Submarine
J3 Submarine
© Unknown

The HMS J3, later HMAS J3, submarine was scuttled off Swan Point to act as a breakwater and power source for the naval base. It settled almost on top of the wreck of the 961 ton coal hulk S.F. Hersey.

The J3 sub is within the Prohibited Area of Swan Island (Department of Defence) and is therefore out of bounds.

The J3 submarine, also known as the Swan Island Sub, lies in 5 to 8 metres with parts of the hull above surface.


The J class of submarines was a seven submarine class developed by Britain's Royal Navy prior to the First World War in response to claims that Germany was developing submarines that were fast enough (22 knts) to operate alongside surface fleets. The rumours were actually false. Six J class submarines were completed during mid-1916, while a seventh entered service at the end of 1917.

The J class Submarine Number 3 was built in 1915/1916 and scuttled in January 1926, the overall length of the vessel was approximately 83.7 metres (275 feet), beam 7.2 metres (24 feet) and draught 4.7 metres (15 feet) giving a displacement weight of 1,092 tonne (1,204 short tons) surfaced. When launched the J class were the fastest subs in existence.

Although larger and more powerful than previous British submarines, the J class could not keep up with surface vessels, and operated independently during the war. Between them, the submarines sank a U-boat, and heavily damaged two battleships, with the loss of one, the J6, to friendly shelling. They were equipped with a powerful long-range wireless they were ideally suited to reconnoiter in enemy water.

Following the war, the six surviving submarines were gifted to the Royal Australian Navy. When they arrived in Australia, they were all in poor condition. The boats were not refitted in England before being handed over and sailing to Australia, and had to undergo extensive refits. They were immediately refitted (from 1920) at the Garden and Cockatoo Island Commonwealth Naval Dockyards.

The ironclad Cerberus acted as a depot ship to the J Class submarines whilst they were stationed at Geelong.

Four subs, J1, J2, J4, and J5, were scuttled in the ship graveyard. Two were scuttled as breakwaters: J3 near Swan Island, and J7 at Sandringham Yacht Club.

See also Wikipedia: HMS J3,
Australian National Shipwreck Database: J-3 Submarine, and
Heritage Council Victoria: J-3 Submarine.

Latitude: 38° 14.640′ S   (38.244° S / 38° 14′ 38.4″ S)
Longitude: 144° 42.120′ E   (144.702° E / 144° 42′ 7.2″ E)

Datum: WGS84 | Google Map
Added: 2012-07-22 01:00:00 GMT, Last updated: 2019-03-23 02:05:23 GMT
Source: GPS
Nearest Neighbour: S.F. Hersey, 149 m, bearing 185°, S
J-Class Submarine, 1820 ton.
Built: Dyfed, Wales, 1916.
Scuttled: January 1926.
Depth: 0 to 8 m.

DISCLAIMER: No claim is made by The Scuba Doctor as to the accuracy of the dive site coordinates listed here. Should anyone decide to use these GPS marks to locate and dive on a site, they do so entirely at their own risk. Always verify against other sources.

The marks come from numerous sources including commercial operators, independent dive clubs, reference works, and active divers. Some are known to be accurate, while others may not be. Some GPS marks may even have come from maps using the AGD66 datum, and thus may need be converted to the WGS84 datum. To distinguish between the possible accuracy of the dive site marks, we've tried to give each mark a source of GPS, Google Earth, or unknown.

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