J2 Broken Submarine

Wreck DiveWreck Dive | Boat access

Deep Rated Outside Port Phillip Slack Water Subject to Shipping Wreck Dive Site

Diesel Electric Submarine | Max Depth: 39 metres (128 feet) — Graveyard

J2 Submarine
J2 Submarine
© Unknown

Completed Nov 1915 at Portsmouth Dock Yard as the HMS J2. At the completion of the first World War in 1919, the British Government gave Australia a gift of six J class submarines and six navy destroyers, thus she became the HMAS J2. All of the submarines were eventually scuttled.

The J2 Submarine was scuttled by explosives on 1 June 1926 about three miles off Barwon Heads. She was found again by the Geelong Skindivers Club on 10 February 1974.

Also known as the J2 Sub, 39 Metre Sub, 130 Foot Broken Sub, Broken Sub or Deep Sub, the wreck lies on its keel running North-South with its bow pointing out to sea. During its scuttling the bow section broke off, exposing the forward torpedoes tubes and bow modifications.

The J2 Submarine is probably the most infrequently dived of the four J class submarines. It is the deepest, and it is also the closest to the Heads. It can, therefore, be uncomfortably close to the path taken by ships entering and leaving Port Phillip. Boat operators must be aware of the shipping traffic during the dive period.

During the Broken Sub's scuttling, explosive charges caused the vessel to break in two sections. The break occurs about 5 metres behind the conning tower. The front half lists to starboard at a 45-degree angle. Over the years the stern has worn down through the reef the wreck sits on.

The wreck is in 39 metres (128 feet) and is surrounded by many schools of fish. These along with the extensive marine growth covering the hull make this an interesting dive for photographers as well as wreck enthusiasts.

Being such a deep dive, it's recommended that divers spend the last few minutes of their limited bottom time at a slightly shallower depth around the conning tower before beginning the final ascent. This area is usually inhabited by large numbers of fish, so there is plenty to look at before returning to the surface.

The Broken Sub is a marvellous venue for the experienced diver. Obviously more than one dive is required to fully explore it. With good visibility, it is an outstanding dive.

Hazards and Precautions:

The 39 metres (128 feet) depth calls for experience and training, correct equipment and very careful planning. Begin your ascent with plenty of air remaining for the inevitable decompression stops. Even at this depth surge can be a problem, especially when penetrating inside the wreck.

If surge is present remain on the outside. If you just swim over the wreck from stern to bow most of the dive will be spent in 33 metres (108 feet).

J2 Submarine plaque, Victoria, Australia
J2 Submarine plaque, Victoria
© Mary Malloy & Allie Beckhurst

Penetration into the wreck is possible, at the point where the ship has been broken, but the need for extreme caution cannot be overemphasised. At 36 metres (118 feet) near the conning tower is a plaque in memory of a diver that died while penetrating the wreck.

In addition to the normal dangers involved in penetration diving at this depth, the Broken Submarine has the additional hazard of extensive jagged and twisted metal around the break.

Once inside the wreck, it can become very dark, so good torches are essential. Silting can occur very easily. Care must be taken to avoid stirring up silt on the bottom, thus further reducing visibility.

J1, J4, J2 alongside HMAS Platypus, circa 1920 
J1, J4, J2 alongside HMAS Platypus,
circa 1920
© Royal Australian Navy

Built in 1915 and scuttled on 1 June 1926, the overall length of the vessel was approximately 83.7 metres (275 feet), beam 7.2 metres (24 feet) and draught 4.3 metres (14 feet) giving a displacement weight of 1,092 tonne (1,204 short tons) surfaced.

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 Lesson To Be Learnt,
Wikipedia: HMS J2,
Australian National Shipwreck Database: J-2 Submarine, and
Heritage Council Victoria: J-2 Submarine.

Latitude: 38° 18.814′ S   (38.31357° S / 38° 18′ 48.85″ S)
Longitude: 144° 34.803′ E   (144.580048° E / 144° 34′ 48.17″ E)

Datum: WGS84 | Google Map
Added: 2012-07-22 01:00:00 GMT, Last updated: 2020-08-24 14:37:06 GMT
Source: Book - Victoria's Ships' Graveyard GPS (verified)
Nearest Neighbour: Lost Reef, 430 m, bearing 154°, SSE
J-Class Submarine, 1820 ton.
Built: Portsmouth, UK, 1915/1916.
Scuttled: 1 June 1926.
Depth: 31 to 39 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.

Suunto D5 at The Scuba Doctor Dive Shop