NAVYPEDIA

Photo

Sprat 1957  

Ships

Names	Builders	Completed	Losses	Transfers	Discarding
X51 Stickleback X52 Shrimp X53 Sprat X54 Minnow	Armstrong-Vickers, Barrow: X51 - 54	1955: X51 - 54	none	Sweden, 7.1958: X51 Stickleback (Spiggen)	1965: X52 Shrimp 1966: X53 Sprat, X54 Minnow

Technical data

Displacement standard, t	32
Displacement normal, t	35 / 39
Length, m	15.4 pp 16.4 oa
Breadth, m	1.80
Draught, m	2.30
No of shafts	1
Machinery	Perkins P6 diesel / electric motor
Power, h. p.	50 / 44
Max speed, kts	6.5 / 6
Fuel, t	diesel oil 1.2
Endurance, nm(kts)
Armament	2 detachable 2t side-charges
Electronic equipment	type 151 sonar
Complement	5
Diving depth operational, m	90

Graphics

Project history

It had previously been assumed that these craft were ordered merely as replacements for worn-out XE-craft, but research into declassified papers in 1994 showed a much more complex history. In 1954 the Royal Navy conceived the idea that a nuclear sea mine could be laid by 'sneak' craft in the approaches to Soviet naval bases such as Kronstadt. At first it was assumed that the payload would be the centre section of the RAFs Mk 1 'Blue Danube' 10,000lb 20kt bomb, but the following year the physics package of a modified 'Red Beard' 2000lb bomb was substituted.

Under the revised Staff Requirement the so-called 'Cudgel' sea mine was to be earned by one of the X51 class (given names in December 1954), and laid at depths down to 90m. Cudgel's timer allowed settings at half-hour intervals from 30 minutes to 12 hours after laying, or at 12-hour intervals from 12 hours to seven days after laying.

The project proved unaffordable because of the shortage of fissile material, and 'Cudgel' was cancelled sometime between late 1955 and mid-1956.

Modernizations

None.

Naval service

Stickleback was sold to the Royal Swedish Navy in 1958 and renamed Spiggen, and Sprat was lent to the US Navy at about the same time, to test harbour defences. Although stricken in 1970 the Spiggen was returned to the UK in 1977 for preservation at the Submarine Museum in Gosport.