NAVYPEDIA

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Ships

Name	No	Yard No	Builder	Laid down	Launched	Comp	Fate
G1	IA3		Chatham DYd	10.1914	14.8.1915	12.1915	sold 2.1920
G2	IA4		Chatham DYd	10.1914	23.12.1915	3.1916	sold 1.1920
G3	IA5		Chatham DYd	10.1914	22.1.1916	3.1916	sold 11.1921
G4	IA6		Chatham DYd	10.1914	23.10.1915	2.1916	sold 6.1928
G5	IA7		Chatham DYd	10/1914	23.11.1915	1/1916	sold 10.1922
G6	IA8		Armstrong, Elswick	12.1914	7.12.1915	5.1916	sold 11.1921
G7	IA9		Armstrong, Elswick	12.1914	4.3.1916	8.1916	sunk 1.11.1918
G8	I0C		Vickers, Barrow	12.1914	1.5.1916	6.1916	sunk 14.1.1918
G9	I1C		Vickers, Barrow	12.1914	15.6.1916	8.1916	sunk 16.9.1917
G10	I2C		Vickers, Barrow	3/1915	11.1.1916	4/1916	sold 1.1923
G11	I3C		Vickers, Barrow	3.1915	22.2.1916	5.1916	wrecked 22.11.1918
G12	I4C		Vickers, Barrow	4.1915	24.3.1916	6.1916	sold 2.1920
G13	I5C		Vickers, Barrow	4/1915	18.7.1916	9/1916	sold 1.1923
G14	I6C		Scotts, Greenock	12.1914	17.5.1917	8.1917	sold 3.1921
G15			White, Cowes	1915	---	---	cancelled 4.1915

Technical data

Displacement standard, t
Displacement normal, t	703 / 837
Length, m	57.0
Breadth, m	6.94
Draught, m	4.07
No of shafts	2
Machinery	G1 - 13: 2 8-cyl Vickers diesels / 2 electric motors G14: 2 FIAT diesels / 2 electric motors G15: 2 MAN diesels / 2 electric motors
Power, h. p.	1600 / 840
Max speed, kts	14.5 / 9
Fuel, t	diesel oil 44
Endurance, nm(kts)	2400(12) / 95(3)
Armament	G1 - 8, 10, 11: 1 x 1 - 76/28 12pdr 8cwt QF Mk I, 1 - 533 TT (stern, 2), 4 - 450 TT (2 bow, 2 beam, 8) G9, 12, 13, 14: 1 x 1 - 76/30 10cwt QF Mk II, 1 - 533 TT (stern, 2), 4 - 450 TT (2 bow, 2 beam, 8)
Complement	30
Diving depth operational, m	30

Standard scale images

Graphics

Project history

The Admiralty, reacting to a rumour in 1913 that almost the whole German U-boat effort had been turned over to double-hulled overseas boats, was panicked into requesting a boat with displacement similar to the 'E' class, a partial double hull, a single 533mm TT forward and two 450mm beam tubes. Out of this emerged the 'G' class, 7 units being ordered under the 1914-15 Estimates: G1-7 were ordered pre-war and G8-13 ordered on 24 November 1914 as part of Fisher's expansion of the submarine force. The firms invited to tender for G6, G7, G14 and G15 were allowed to install their own diesels, so Armstrong Whitworth proposed to put MAN Nuremberg type in G6, and Sulzers in G7; Scott's proposed to put FIAT engines into G14 and White proposed to put their license-built MAN type into G15 (cancelled in 1915). The impossibility of getting German diesels led to G6 and G7 being engined with Vickers standard diesels. The standard 'G's had the same diesel as the 'E's, so to speed up production of existing 'E's Chatham DYd were allowed to divert the diesels ordered for G2-5 into E19-32. The engines were presumably replaced by engines built at Chatham. During construction the armament was changed. The 533mm tube was moved aft and two 450mm bow tubes were substituted. The 'G's thus introduced the 533mm torpedo to British submarines, although Swordfish had been ordered a year earlier.

Modernizations

1916-1917, G2-8, G10, G11: - 1 x 1 - 76/28; + 1 x 1 - 76/30 10cwt QF Mk II

1917-1918, 5 submarines: + 1 x 1 - 40/37 2pdr QF Mk III

Naval service

G7 and G8 were lost 1.11.1918 and 1.5.1916 by unknown causes in the North Sea. G9 was sunk 16.9.1917 off Norway in error by RN destroyer Petard. G11 wrecked during a storm off Harwich 22.11.1918.