NAVYPEDIA

Photo

H27 1919

Ships

Name	No	Yard No	Builder	Laid down	Launched	Comp	Fate
H21			Vickers, Barrow	3.1917	20.10.1917	1.1918	sold 7.1926
H22			Vickers, Barrow	3.1917	14.11.1917	11.1918	sold 2.1929
H23			Vickers, Barrow	3.1917	29.1.1918	4.1918	sold 5.1934
H24			Vickers, Barrow	3.1917	14.11.1917	5.1918	sold 5.1934
H25			Vickers, Barrow	3.1917	27.4.1918	7.1918	sold 2.1929
H26			Vickers, Barrow	3.1917	15.11.1917	3.1918	sold 4.1928
H27			Vickers, Barrow	3.1917	25.9.1918	1.1919	sold 8.1935
H28	28H, N28		Vickers, Barrow	3.1917	12.3.1918	6.1918	sold 9.1944
H29			Vickers, Barrow	3.1917	8.6.1918	9.1918	foundered in dock 9.8.1926
H30			Vickers, Barrow	3.1917	9.5.1918	10.1918	sold 8.1935
H31	31H, N31		Vickers, Barrow	4.1917	16.11.1918	2.1919	sunk 24.12.1941
H32	32H, N32		Vickers, Barrow	4.1917	19.11.1918	5.1919	sold 10.1944
H33	33H, N33		Cammell Laird, Birkenhead	11.1917	24.8.1918	5.1919	BU 10.1944
H34	34H, N34		Cammell Laird, Birkenhead	11.1917	5.11.1918	9.1919	BU 7.1945
H35			Cammell Laird, Birkenhead	1917	---	---	cancelled 10.1917
H36			Cammell Laird, Birkenhead	1917	---	---	cancelled 10.1917
H37			Cammell Laird, Birkenhead	1917	---	---	cancelled 10.1917
H38			Cammell Laird, Birkenhead	1917	---	---	cancelled 10.1917
H39			Cammell Laird, Birkenhead	1917	---	---	cancelled 10.1917
H40			Armstrong, Elswick	1917	---	---	cancelled 10.1917
H41			Armstrong, Elswick	1917	26.7.1918	---	cancelled 1918
H42			Armstrong, Elswick	10/1917	21.10.1918	5/1919	collision 23.3.1922
H43	43H, N43		Armstrong, Elswick	10.1917	3.2.1919	11.1919	BU 11.1944
H44	44H, N44		Armstrong, Elswick	10.1917	17.2.1919	3/1920	BU 2.1945
H45			Armstrong, Elswick	1917	---	---	cancelled 10.1917
H46			Armstrong, Elswick	1917	---	---	cancelled 10.1917
H47			Beardmore, Dalmuir	11.1917	19.11.1918	2.1919	collision 9.7.1929
H48			Beardmore, Dalmuir	11/1917	31.3.1919	6/1919	sold 8.1935
H49	49H, N49		Beardmore, Dalmuir	7.1917	15.7.1919	9.1919	sunk 27.10.1940
H50	50H, N50		Beardmore, Dalmuir	1.1918	25.10.1919	2.1920	BU 7.1945
H51			Pembroke DYd	10/1917	15.11.1918	9/1919	sold 6.1924
H52			Pembroke DYd	1.1918	31.3.1919	12/1919	sold 11.1927

Technical data

Displacement standard, t
Displacement normal, t	423 / 510
Length, m	52.4
Breadth, m	4.80
Draught, m	4.03
No of shafts	2
Machinery	2 NLSE diesels / 2 electric motors
Power, h. p.	480 / 620
Max speed, kts	11.5 / 10.5
Fuel, t	diesel oil 16
Endurance, nm(kts)	2975(7.5) / 130(2)
Armament	4 - 533 TT (bow, 6 - 8)
Complement	22
Diving depth operational, m	30

Standard scale images

Graphics

Project history

In January 1917 an order was placed with Vickers for 12 boats similar to the 'H' class but with 533mm TT. Engines, main motors and major fittings were obtained from the United States. In June 1917 a second batch was ordered, 6 from Cammell Laird, 8 from Armstrong Whitworth, 4 from Beardmore, 2 from Pembroke DYd and 2 from Devonport DYd, using engines and motors made in England to US designs, but otherwise identical to those in H1-20 and H11-32. The order was cut back when it was decided in October 1917 to build 12 'R' class (using many of the H21 class components). Another was cancelled shortly after the Armistice, so only 22 out of 34 were completed. The main differences between these and the earlier 'H' class resulted from fitting 533mm TT; the hull was 6.4m longer but the diameter of the pressure hull was the same. Displacement went up by 16%. Despite their small reserve of surface stability, inherent in a single-hulled design, they were most successful and some survived to serve in the Second World War, although nominally restricted to training duties.

Modernizations

1922 - late 1920s, some survived: + type 113 sonar

1942- 1944, survived: + type 286W or type 291W radar

Naval service

Н49 was sunk 18.10.1940 by German trawlers UJ116 and UJ118 off Dutch coast. Н31 was lost for the unknown reason in Bay of Biscay 24.12.1941. H29 foundered 9.8.1926 in dock at Devonport, raised and sold in October 1927. H42 collided with destroyer Versatile 23.3.1922 off Gibraltar and sunk. H47 collided with L12 and sunk 9.7.1929.