J Class

Group One and Group Two

Overseas Submarine

  • J Class Submarine
  • J1
  • J2
  • J3
  • J5
  • J7
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These boats resulted from an Admiralty theory that submarines should have the capability to operate with the main fleet, this obviously required a much higher surface speed than submarines of the time were capable of. These submarines would be referred to as 'Fleet Submarines'.

On completion they were only able to achieve 19 knots which was deemed to be too slow to work with the fleet and as a result they were reclassified as 'Overseas' Submarines.

6 Built

J1, J2.
HM Dockyard, Portsmouth.
1915 - 1916

J3, J4.
HM Dockyard, Pembroke.
1915 - 1916

J5, J6.
HM Dockyard, Devonport.
1915 - 1916

Technical Information

1,210 sf
1,820 sm

Length (ft):

Breadth (ft):

Draught/Height (ft):

Vickers-Admiralty Diesel engines 3,600 hp
2 Electric Motors 1,350 hp.
3 screws.

Speed (kts):
19 knots sf
9.5 knots sm

Oil Supply (tons):
91 max

6 x 18 inch tubes (bow), 2 beam.
1 x 3 inch QF, 1 x 2 pdr pom-pom.

5,000 nm at 12.5 kts sf

44 Officers and Ratings