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J2 Broken Submarine

Wreck Dive Wreck Dive | Boat access Boat access

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

Diesel Electric Submarine | Max Depth: 39 m (128 ft) — Graveyard

J2 Submarine in Victoria
J2 Submarine in Victoria
Source: State Library Victoria

The J2 Submarine shipwreck, also known as the J2 Sub, 39 Metre Sub, 130 Foot Broken Sub, Broken Sub or Deep Sub, 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 diving period.

Diviving the J2 Submarine

Diving the J2 Submarine
Diving Diving the J2 Submarine
© Ian Scholey

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 m (128 ft) 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.

J2 Submarine Conning Tower
J2 Submarine Conning Tower
© Ian Scholey

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.

Dive charter boats sometimes schedule dives on the J2 Submarine, heading out from Portsea and Queenscliff. Private dive boats usually launch at the Sorrento Boat Ramp or the Queenscliff Boat Ramp.

Bass Strait Warning: Always keep an eye on sea conditions throughout any shore or boat dive in Bass Strait on Victoria's coastline. Please read the warnings on the web page diving-in-bass-strait before diving or snorkelling this site.

Hazards and Precautions Diving the J2 Submarine

The 39 m (128 ft) 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 there is surge present, remain on the outside. If you just swim over the wreck from stern to bow most of the dive will be spent at 33 m (108 ft).

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 m (118 ft) near the conning tower is a plaque in memory of a diver that died while penetrating the wreck. See also Lesson To Be Learnt about a fatality while diving the J2 Submarine.

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.

J2 Submarine History

J2 Submarine in the Suez Canal
J2 Submarine in the Suez Canal
Source: Australian War Memorial

Originally HMS J2, later HMAS J2, this is one of the J class submarines designed and built during WW1 by the British Royal Navy. The J class of submarines was a seven submarine class developed in response to claims that Germany was developing submarines that were fast enough (22 knots) to operate alongside surface fleets. The rumours were actually false.

The J Class design brief was for a submarine to operate on the wings of battle fleets, diving at the commencement of engagements, and picking off stragglers, damaged ships, and acting as an anti-submarine submarine.

This class of submarines were the only design of submarines ever to have had 3 screw propellers, and at the time were the fastest subs around with a surface speed of 19 knots (35 kpm). Six J class submarines were completed during mid-1916, while a seventh entered service in 1917.

HMS J2 commissioned in the Royal Navy on 1 June 1916 under the command of Lieutenant Commander AM Winser RN and was allocated to the 11th Submarine Flotilla based at Blyth, Northumberland. On 31 July 1916 J2 departed Portsmouth for Blyth. The wartime complement was 5 officers and 40 sailors.

HMS J2 Submarine Operations

J Class Submarine Control Room
J Class Submarine Control Room
Source: Royal Navy
In June 1917 it was decided to conduct a large scale operation using both destroyers and submarines to flush out enemy submarines either leaving for patrol or returning to their bases from the Atlantic. Known as Operation BB, it was planned to force enemy submarines to dive through certain areas heavily patrolled by destroyers so that they would be on the surface while passing through adjacent areas patrolled by British submarines. The British submarines employed included J1, J2, J4 and J5. During the ten days, 15 to 24 June, 19 German submarines passed in or out of the North Sea; 12 homeward bound and seven outward bound. There were 26 sightings and 11 attacks made, eight by destroyers and three by submarines. J2 was allocated to an area extending west south-west from the Norwegian coast off Stavanger but saw nothing of the enemy.

At 07:40 on 7 July 1917, when on the surface in position 58°N, 03°05'E, J2, at this time commanded by Lieutenant VM Cooper RN, sighted an enemy submarine also on the surface at 4500 yards, and fired four torpedoes. A column of black smoke appeared in the vicinity of the enemy's conning tower, the enemy remained in sight for a few seconds and then disappeared. No explosion was heard on J2's bridge or in the torpedo room though one was heard in the engine room. At the time a hit was not allowed, though U-99, which according to German records was in the area at that time, did not return from patrol.

On 2 August 1917, at about 08:00, J2 was on the surface proceeding to her patrol area at 15 knots when she sighted some ships. The submarine dived and the Commanding Officer commenced an attack. The weather was perfect and the sea a glassy calm. However, on discovering that the ships were British the attack was broken off and the Commanding Officer decided to bottom in 125 feet until they were clear. Even so, the destroyers gained contact and attacked with depth charges, several attacks were quite close and some damage was done. The submarine remained stationary and silent on the bottom and by 15:30 the surface ships had lost contact and gone away. J2 surfaced and resumed her patrol.

In 1918 J2 was sent to Liverpool to refit, and was there when the Armistice was signed.

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. The J6 Submarine had been sunk in error in 1918 by a British ship.

HMAS J2 Submarine Operations

J2 alongside HMAS Platypus in Aden
J2 alongside HMAS Platypus in Aden
Source: Royal Australian Navy

Following the conclusion of hostilities in World War I, the Admiralty in 1918 presented the six remaining boats of the J Class, plus six navy destroyers, to the Australian Government. All the submarines commissioned into the Royal Australian Navy at Portsmouth on 25 March 1919, as tenders to the submarine depot ship HMAS Platypus. The Commanding Officer of J2 was Lieutenant Claud B Barry DSO, RN.

The beam tubes were removed from all six J Class submarines before they sailed for Australia. The tubes were despatched separately to Garden Island. The reasons given for the removal were that the beam tubes were not a success and that increased accommodation was required.

J2 Submarine on passage to Australia
J2 Submarine on passage to Australia
Source: Royal Australian Navy

On 9 April 1919, HMAS Platypus and the submarines, escorted by the light cruiser HMAS Sydney, sailed from Portsmouth for Australia, their first two ports of call being Gibraltar and Valetta. Other ports of call included Port Said, Aden, Colombo, Singapore, Thursday Island, and Brisbane. When they arrived in Sydney, Australia on 15 July 1919, the six submarines were all in poor condition. They were taken in hand at Garden Island Dockyard for refitting.

After her refit was completed in May 1920, HMAS J2 sailed on 3 May 1920, in company with J5, for the submarine base at Geelong, Victoria. Osborne House, previously a rest home for nurses, was used as the base for the six submarines. The ironclad Cerberus was renamed HMAS Platypus II on 1 April 1921 and acted as a depot ship to the J Class submarines whilst stationed at Geelong. The HMAS Platypus II is not to be confused with the HMAS Platypus which was one of the six gift vessels which escorted the J submarines from England to Australia.

The J1, J2, J4 and J5 submarines carried out a major cruise in Tasmanian waters in January 1921.

After uneventful service, little of which was spent at sea, J2 and her five sisters paid off into Reserve and decommissioned at Western Port on 12 July 1922. The boats had become victims of the worsening economic conditions of the time, coupled with their high cost of maintenance.

J2 Submarine Details

J-class Submarine General Arrangement
J-class Submarine General Arrangement
Source: Royal Australian Navy

The J2 Submarine was built in 1915 at Portsmouth Naval Dockyard, England, launched on 6 November 1915 as a double-hulled type, triple screw submarine. At that time the J class were the fastest subs in existence.

It's commonly believed that the J-class submarines were identical in dimensions and layout, but this is not so. Royal Navy drawings placed the J class into two groups of J1–4 and J5–7, and that the bridge of J7 was moved 60 feet aft compared to J5–6. Plans show a difference in overall length between the two groups, with J5–7 at 274 feet 9 inches being 9 inches shorter than J1–4 which were 275 feet 6 inches.

The overall length of the J2 Submarine was approximately 275.5 ft (84 m), beam 23.25 ft (7.09 m) and draught 16 ft (4.88 m) giving a displacement weight of 1,210 t (1,334 s-ton) surfaced and 1,820 t (2,006 s-ton) submerged.

Inside a J-class Submarine
Inside a J-class Submarine
Source: Royal Australian Navy

The J-class submarines were powered by three 12-cylinder Vickers solid injection, direct reversing, 4-cycle, diesel engines of 14.5-inch bore and 14-inch stroke, producing a total of 3,600 HP at 380 rpm. For submerged running there were two Mather & Platt 700 HP electric motors, for a total of 1,400 HP, powered by four banks of 58 cell batteries.

The vessel had a maximum speed of 19 knots (35 kpm) surfaced and 9.4 knots (17 kpm) submerged, with a range of 4,000 nm (7,408 km) at 12 knots (22 kpm) and 2,250 nm (4,167 km) at full speed surfaced. The maximum safe diving depth was 300 ft (91 m). The J-class submarines were equipped with a powerful long-range wireless and were ideally suited to reconnoitre in enemy water.

The J Class submarines principal weapons originally were:

  1. 6 x 18-inch (457 mm) torpedo tubes (4 bow, 2 beam)
  2. 1 x 4-inch (102 mm) gun
  3. The J1, for a brief period, was fitted with Depth charges

J2 Submarine Scuttling

The decision to scrap the submarines J1 to J5 was taken on 19 November 1923 following a cut in the defence budget by some 500,000 pounds. In January 1924 the Melbourne Salvage Company purchased the J1, J2, J4 and J5 submarines for 10,500 pounds. The purchasers were under a bond of 1,000 pounds to the Defence Department as a guarantee of the final destruction of the submarines. The contract also included the sinking in deep water or breaking up or otherwise disposing of the submarines to the satisfaction of the government contract board.

The J2 Submarine was scuttled on Tuesday 1 June 1926 in 120 feet of water three miles off The Heads. The submarine was towed down Port Phillip by the tug Minah which left Williamstown at 3:30 am. The Air Force, hearing that the vessel was to be sunk, considered that the submarine would be a good target for bombing practice. When the tug, with her tow, arrived at the dumping ground, the seacocks of the J2 were opened, and the Minah then steamed away to a safe distance. Meanwhile, seaplanes, equipped with a number of TNT bombs, circled around at a height of 3,000 feet. One bomb fell close alongside, and the submarine turned up on end and sank in the Victorian Ships' Graveyard, Bass Strait.

There are accounts that during the scuttling target practice was made of the J2 Submarine, as above. Other accounts say this happened during the scuttling of the J5 Submarine.

J2 Submarine Wheel
J2 Submarine Wheel,
HMAS Castlemaine Museum ship
© Royal Australian Navy

The wheel from the J2 Submarine is on display at the ex HMAS Castlemaine at Williamstown.

The J2 Submarine was found again by the Geelong Skindivers Club on 10 February 1974.

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

See also Lesson To Be Learnt about a fatality while diving the J2 Submarine,
Heritage Council Victoria: J-2 Submarine,
Australian National Shipwreck Database: J-2 Submarine,
Royal Australian Navy: HMAS J2,
WW1 J Class Submarines,
WW1 J Class Subs,
Wikipedia: HMS J2, and
Wikipedia: J-class submarine.

Heritage Warning: Any shipwreck or shipwreck relic that is 75 years or older is protected by legislation. Other items of maritime heritage 75 years or older are also protected by legislation. Activities such as digging for bottles, coins or other artefacts that involve the disturbance of archaeological sites may be in breach of the legislation, and penalties may apply. The legislation requires the mandatory reporting to Heritage Victoria as soon as practicable of any archaeological site that is identified. See Maritime heritage. Anyone with information about looting or stolen artefacts should call Heritage Victoria on (03) 7022 6390, or send an email to

Finding the J2 Broken Submarine

Over the years we've been provided with many GPS marks for the J2 Broken Submarine. The GPS marks we know of in circulation for the J2 Broken Submarine are:

  • Book - Victoria's Ships' Graveyard GPS (verified):
    Latitude: 38° 18.814′ N   (38.31357° N / 38° 18′ 48.85″ N)
    Longitude: 144° 34.803′ E   (144.580048° E / 144° 34′ 48.17″ E)
  • Geoff Rodda:
    Latitude: 38° 18.817′ S   (38.313616666667° S / 38° 18′ 49.02″ S)
    Longitude: 144° 34.831′ E   (144.58051666667° E / 144° 34′ 49.86″ E)

    41 m, bearing 97°, E
Wathaurong (Wadda-Warrung) country
Wathaurong (Wadda-Warrung) country

Traditional Owners — This dive site is in the traditional Country of the Wathaurong (Wadda-Warrung) people of the Kulin Nation. This truly ancient Country includes the coastline of Port Phillip, from the Werribee River in the north-east, the Bellarine Peninsula, and down to Cape Otway in the south-west. We wish to acknowledge the Wathaurong as Traditional Owners. We pay respect to their Ancestors and their Elders, past, present and emerging. We acknowledge Bunjil the Creator Spirit of this beautiful land, who travels as an eagle, and Waarn, who protects the waterways and travels as a crow, and thank them for continuing to watch over this Country today and beyond.


J2 Broken Submarine Location Map

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 09:00:00 GMT, Last updated: 2022-04-28 15:49:55 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.
Victorian Ships' Graveyard, Bass Strait.
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.


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