NAVYPEDIA

Photo

R4

Ships

Name	No	Yard No	Builder	Laid down	Launched	Comp	Fate
R1			Chatham DYd	2/1917	25.4.1918	10/1918	sold 1.1923
R2			Chatham DYd	2/1917	25.4.1918	12/1918	sold 2.1923
R3			Chatham DYd	2/1917	8.6.1918	3/1919	sold 2.1923
R4			Chatham DYd	2.1917	8.6.1918	8/1919	sold 5.1934
R5			Pembroke DYd	1917	---	---	cancelled 1919
R6			Pembroke DYd	1917	---	---	cancelled 1919
R7			Vickers, Barrow	11/1917	14.5.1918	6/1918	sold 2.1923
R8			Vickers, Barrow	11/1917	28.6.1918	7.1918	sold 2.1923
R9			Armstrong, Elswick	12/1917	12.8.1918	10.1918	sold 2.1923
R10			Armstrong, Elswick	12/1917	5.10.1918	4/1919	sold 2.1929
R11			Cammell Laird, Birkenhead	12/1917	16.3.1918	8/1918	sold 2.1923
R12			Cammell Laird, Birkenhead	12/1917	9.4.1918	10/1918	sold 2.1923

Technical data

`	6 - 450 TT (bow, 12)
Displacement standard, t
Displacement normal, t	410 / 503
Length, m	49.9
Breadth, m	4.65
Draught, m	3.51
No of shafts	1
Machinery	1 NLSE diesel / 2 electric motors / 1 electric motor for slow running
Power, h. p.	240 / 1200 / 25
Max speed, kts	9.5 / 15
Fuel, t	diesel oil 13
Endurance, nm(kts)	2000(8) / 240(4)
Complement	22
Diving depth operational, m	75

Standard scale images

Graphics

Project history

This class, the first anti-submarine 'hunter-killers', were 30 years ahead of their time. In March 1917 the DNC's department submitted a design of submarine fast enough to overtake enemy submarines and sink them with torpedoes, rather than gunfire. The design was not approved, but later that year when Commodore (S) suggested the idea should be developed, it was resurrected and orders were placed in December (armament increased from four to six TT). The hull reverted to the 'spindle' shape of the 'Hollands' and 'A' to 'C classes, and hull-sections were the same as the H21 class to save time (they were ordered in place of cancelled 'H' boats). The propulsion unit was a single 'H' engine, but a 'J' class 220-cell battery was used to boost underwater speed. An unusual step was the provision of a small 25hp auxiliary motor mounted on the shaft, for slow running. The bow compartment contained five powerful and sensitive hydrophones, with bearing measurement lo allow torpedoes to be fired underwater. Although the single shaft made them hard to manoeuvre on the surface, the streamlined hull and large rudder gave them good underwater performance. Unfortunately the only engagement in which their unique capabilities could be used - R8's October 1918 attack on a U-boat - was marred by a faulty torpedo, and they were discarded early.

Modernizations

None

Naval service

No significant events.