Capetown Class Cruiser (1918)

The five light cruisers of the Capetown Class (or, sometimes, Cairo Class) were completed between 1919 and 1922. They were follow-on units of the Ceres class, and generally completed after their design successors, the Danae class.

Overview of 5 vessels
Citations for this data available on individual ship pages
Name	Builder	Laid Down	Launched	Completed	Fate
Capetown	Cammell Laird	23 Feb, 1918	18 Jun, 1919		Sold Apr, 1948
Cairo	Cammell Laird	28 Nov, 1917	19 Nov, 1918	10 Oct, 1919	Sunk
Calcutta	Vickers	18 Oct, 1917	9 Jul, 1918		Sunk
Carlisle	Fairfield Shipbuilding and Engineering Company	2 Oct, 1917	9 Jul, 1918		Sold 1948
Colombo	Fairfield Shipbuilding and Engineering Company	8 Dec, 1917	18 Dec, 1918	18 Jun, 1919	Sold 22 Jan, 1948

Machinery

Generators

In 1916, it was stated that ""C" and "D" class light cruisers" have three 52.5 kw dynamos at 105 volts. It is unclear whether this outfit was still deemed sufficient for this later class.

Armament

The ships were armed as follows.

Guns

• Five 6-in 45cal B.L. Mark XII guns on the centre-line with a maximum elevation of 30 degrees. The guns had armoured shields of 1/4 inch on the face, 3/16 inch on sides and top, weighing 1.25 tons.
• Two 3-in 20cwt Q.F. on H.A. mountings
• Four 3-pdr
• Two 2-pdr pom-poms

Torpedoes

• four 21-in D.R. Mark II* (?) above water tubes (4x2) disposed in pairs abreast, bearing 60-120 degrees.

As the 6-in guns fired over these, they proved untenable for manned firing as the 6-in guns would have necessitated a blast shield projecting fully 18 feet from the muzzle. The ugly expedient taken was to train the tubes to a pre-arranged bearing on coming to action stations and to use remote firing from the primary and secondary control positions.

In 1918, the Capetown class was one of several light cruiser classes ordered to receive refits so that their A.W. torpedo tubes would use two impulse charges firing in a cascade to increase the torpedo discharge velocity and thus reduce the angle at which the torpedoes entered the water. However, the Capetowns may have later been excluded from this alteration, as Mark II* tubes were found not to be suitable candidates for the re-work.

Fire Control

Mechanical Aid-to-Spotter

By 1919, all the ships were likely equipped with four Mechanical Aid-to-Spotter Mark II*s with Elliott's Bearing Transmitters. The installations generally consisted of placing one on each side of the foretop, driven by flexible shafting from a gearbox on the director tower.

Supplies of these devices begane in June 1918.

Range Dials

As of 1920, all five ships had two Range Dial Type Cs with 10 foot dials and a Range Dial Type L.

Rangefinders

They were to be supplied an additional 9-foot rangefinder aft, specifically to augment torpedo control.

By 1921, the ships were equipped as follows:

• Fore bridge, port and starboard: two 12ft F.Q. 2 on M.Q. 12 mountings
• After control: 12ft F.Q. 2 on M.Q. 1
• High Angle: 2m F.T. 29 on M.T. 10

Evershed Bearing Indicators

These ships almost certainly had Evershed gear for gun control from delivery, and would also feature Evershed installations for searchlight control after orders for such installations from February 1917.

Directors

All ships were completed with gunnery directors in place.

The director was in a tower on a pedestal mounting and was probably augmented by use of their 'X' gun as a directing gun. ^[Inference]

Dreyer Table

All five ships are listed in the Dreyer Handbook of 1918 as having a Dreyer Table Mark III*. As of 1930's pamphlet on this table, they are all still so equipped.

Torpedo Control

In 1916, it was decided that all light cruisers of Bristol class and later should have torpedo firing keys (Pattern 2333) fitted on the fore bridge, in parallel with those in the CT, and that a flexible voice pipe be fitted between these positions.

By 1917, modifications to the torpedo control voice pipe system were desired. The voice pipes (port and starboard) to the CT were ordered to be removed in 1917, and in 1918, stop cocks were to be added to permit the after control position to be chopped out to improve the acoustic efficiency of the networks to the remaining rangefinder platform control position forward.

In mid-1920, it was decided that the ships in this class should each receive a Renouf Torpedo Tactical Instrument Type A.

See Also

• Wikipedia

Bibliography

• Admiralty, Gunnery Branch (1917). The Director Firing Handbook. O.U. 6125 (late C.B. 1259). Copy No. 322 at The National Archives. ADM 186/227.
• Admiralty, Gunnery Branch (1910). Handbook for Fire Control Instruments, 1909. Copy No. 173 is Ja 345a at Admiralty Library, Portsmouth, United Kingdom.
• Admiralty, Gunnery Branch (1918). Handbook of Captain F. C. Dreyer's Fire Control Tables, 1918. C.B. 1456. Copy No. 10 at Admiralty Library, Portsmouth, United Kingdom.
• Admiralty, Technical History Section (1919). The Technical History and Index: Fire Control in H.M. Ships. Vol. 3, Part 23. C.B. 1515 (23) now O.U. 6171/14. At The National Archives. ADM 275/19.
• Admiralty, Gunnery and Torpedo Division (July, 1919). Progress in Naval Gunnery, 1914-1918. C.B. 902. The National Archives. ADM 186/238.