J Class Submarine SCUBA Dive Sites

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Since 10-03-02

Updated 11-01-03 dead links culled

J Class Submarines: There are six World War I, J Class submarines located in Victorian waters J1, J2, J3, J4, J5 and J7.   The six subs were presented to Australia by the British Admiralty on 25 March 1919 and arrived in Australia in July 1919, eventually being disposed of between 1926 and 1930 due to their high operating costs and lack of reliability.

Specs:

Class Displ't BHP EHP Speed Surface Speed Submerged Endurance Tubes Comp't
J7 1200/1760 3600 hp 1400 hp 19.5 kts 9.5 kts 4,000 m
at 12 kts		 6: 4 bow, 2 beam 44
J1 - J5 1260/1820 3600 hp 1400 hp 19.5 kts 9.5 kts 4,000 m
at 12 kts		 6: 4 bow, 2 beam 44

The J class subs had six 18 inch torpedo tubes and one 4 inch gun. The 4 inch guns on J1 - J5 were on the conning tower and J2 - J5 had revolving breast work to the gun. J1s gun platform was mounted on pillars and old photos of J7 show the gun located forward of the conning tower on the deck.

Dimensions: 270 feet (p.p), 274.75 feet (o.a) x 23.5 feet x 14 feet

Engines: 3 sets of Vickers 12 cylinder solid injection, direct reversing 4 cycle 1200 B.H.P Diesel engines (14.5 in bore x 15 in stroke), 380 r.p.m.

Fuel: oil 80/91 tons.

When completed the J class were the fastest submarine in the world and were built to counter the erroneous reports that Germany was building subs with a top speed of 18-20 kts.

J1 (36 Metre Sub, 120 Foot Sub, Winged Sub or Deep Intact Sub): Completed Nov 1915 at Portsmouth Dock Yard.

GPS: S 38° 18.741 E144° 34.053 (AUS66)

J2 (38 Metre Sub, Broken Sub or Deep Sub): Completed Nov 1915 at Portsmouth Dock Yard. The Broken Sub lies in 38 metres of water and is broken in half about 5 metres behind the conning tower. The front half lists to stb at 45 degrees and the stern has worn down through the reef the wreck sits on over the years. At 36 metres near the conning tower is a plaque in memory of a diver that died while penetrating the wreck. Penetration is possible at the break but care should be taken when entering the wreck as silting can occur very easily. If you just swim over the wreck from stern to bow most of the dive will be spent in 33 metres. The wreck site is subject to currents and should only be dived by experienced divers. 

GPS: S 38° 18.893 E144° 34.737 (AUS66)

J4 (26 Metre or 90 Foot Sub): Completed Feb 1916 at Pembroke Dock Yard. J4 is broken in half and is the shallowest of the subs located outside Port Phillip Bay.

GPS: S 38° 18.096 E144° 33.749 (AUS66)

Image of a J4 Sub    Old photo of J4 next to J1 (showing J1s gun on pillar deck)

J5 (Intact Sub): Completed Sept 1915 at Devenport Dock Yard.

J3 (Swan Island Sub): Completed Dec 1915 at Pembroke Dock Yard and is now located on the northeast end of Swan Island with the conning tower clearly visible above water.

J7 (Sandringham Yacht Club Sub): Completed Feb 1917 at Devenport Dock Yard and is now located at Sandringham Yacht Club. J1 to J5 have the same hull shape, although the conning towers are different. J7 has a different hull shape and the conning tower is set further aft than the other J’s.

J6 was sunk by friendly fire during WWI.

For further info take a look at the following weblink J Class Subs