Dive Site - J2 Submarine
| Dive Site - J2 Submarine | |||
| Dive Location: | City / Island: | ||
| J2 Submarine | The Heads, Bass Strait, VIC | ||
| Country: | Rating: | Max. Depth: | Difficulty: |
| Australia |  |
39 m | Advanced Open Water plus Deep |
| Aquatic Name: | Water: | Altitude: | |
| - | Salt | 0 m | |
| GPS Latitude: | GPS Longitude: | GPS Datum: | |
| 38° 18.814′ S 38.313567° S 38° 18′ 48.84″ S |
144° 34.803′ E 144.58005° E 144° 34′ 48.18″ E |
Google Map | WGS84 |
| 1 dive at this location: | |||
| 52 | |||
| Map: | |||
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| 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. DIVING THEE J2 SUBMARINE Entry/Exit: Boat. During the J2 Submarine's scuttling, explosive charges caused the vessel to break in two sections, hence the name Broken Sub. 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. 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 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). 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 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. J2 SUBMARINE DETAILS 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. 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. 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. 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. Location GPS coordinates from the book "Victoria's Ships' Graveyard" are GPS verified. See also: https://www.borrett.id.au/downloads/dive_article_lessons_to_be_learnt.pdf |
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