Calliope Class Cruiser (1914)

The two light cruisers of the Calliope Class were completed in 1915. Some contemporary sources regard them as a subclass of the Cambrian class.

Overview of 2 vessels
Citations for this data available on individual ship pages
Name	Builder	Laid Down	Launched	Completed	Fate
Calliope	Chatham Royal Dockyard	1 Jan, 1914	17 Dec, 1914	Jun, 1915	Sold 28 Aug, 1931
Champion	Hawthorn Leslie & Company	9 Mar, 1914	29 May, 1915	Dec, 1915	Sold 28 Jul, 1934

Performance

The ships' capacity for 895 tons of fuel, delivered the following endurance.

Knots	Tons / hour	Endurance (hours)	radius (nm)
14	2.7	326	4,564
16	3.2	375	6,000
18	3.8	332	5,976
20	4.7	188	3,760
22	5.8	152	3,344
24	7.4	119	2,856
26	10.0	88	2,288
28	13.4	57	1,596

Binoculars

In September 1914, the ships were allowed six additional pairs of Pattern 343 Service Binoculars.

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 possible that this description applies to this class.

Armament

Guns

The ships of Caroline, Calliope and Cambrian classes had their gun armament increased as the war went on.

Original:

• Two 6-in 45cal B.L. Mark XII guns aft on P. VII mountings (one source indicates P. VII*), able to elevate 15 degrees.
• Eight semi-automatic 4-in 45cal Q.F. Mark V guns; 2 in tandem forward, 3 on each beam

This configuration drew criticism and it was proposed in 1915 to place a third gun forward in lieu of the pair of 4-in guns originally situated there as:

• the 6-in guns had superior range and hitting power
• the German 4.1-in gun on the opposing light cruisers was found to outrange the British 4-in Q.F. Mark V guns
• intelligence indicated that the next German light cruisers might move to 5.9-in guns and the older ships may also get larger weapons
• it was desired to augment the firepower in closing actions

This resulted in the configuration, decided upon in June 1916 to effect the alteration (all completed by summer 1917) for the 12 ships described as the "Calliope class", but almost certainly indicating Calliope, Cambrian and Caroline classes:

• Two tandem 4-in guns forward replaced by third 6-in gun.
• one 4-in H.A. gun on an ad hoc "H.A. I" or "H.A. II" mounting to replace 3-pdr Vickers H.A. gun, with a second to appear when guns and proper H.A. III mountings became available.

The 6-in mountings were modified to a 20 degree elevation limit, increased from the original limit of 15 degrees, as the ships were refitted for director firing in late 1917-1918. It is not clear whether their elevation receivers, originally restricted to 15 degree indications, were updated.{DirectorH\p. 144}}

In October 1916, Commodore, Harwich Force recommended removing all 4-in guns but the forward-most pair which would be converted to H.A. mountings. By removing five 4-in guns, a fourth 6-in gun could be mounted abaft the funnel. A variation on this was to be applied in 1918, though logistics slowed the work:

• all 4-in guns removed except the single H.A. mounting (presumably, H.A. III. There is no solid evidence that the second one was ever shipped)
• Fourth 6-in gun on elevated CL platform abaft funnels (on P VII* mountings, as the P VII supplies were nil)

A final 1918 rearmament was to provide two 3-in H.A. guns in the positions where 4-in H.A. guns had previously been discussed. This plan was never was put into effect.

By the end of 1918, only Champion had four 6-in P. VII 20 degree mountings and one 4-in H.A. gun. Calliope had merely had her three 6-in mountings modified for 20 degree elevation, but was brought up to spec after the Armistice and prior to 1921.

Torpedoes

Two Service Bar 21-in submerged broadside tubes amidships depressed 2 degrees and bearing 90.

These could not be fired at speeds over 24 knots, as divergent waves would make depth-taking very uncertain.

Fire Control

Mechanical Aid-to-Spotter

By 1920, these ships were equipped with Mechanical Aid-to-Spotter Mark II*s with Evershed 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 began in June 1918.

Range Dials

As of 1920, none of the ships seem to have been equipped.

Rangefinders

A confusing decree from 1918 indicates that Calliope may have been the testbed for a modification in which the aft torpedo control position's roof would be lowered so that a 12-foot R.F. could be situated atop it.

Evershed Bearing Indicators

The Centaur class were the first light cruisers fitted with Evershed gear for gun control, but it is not clear whether older light cruisers were ever fitted.

Orders for Evershed installations for searchlight control from February 1917 first applied to the Danae class, but seem unlikely to have applied to earlier ships.

Directors

In 1916, it was approved that the ships of this class should be retrofitted with directors as time, resources and opportunity permitted. This intention was reiterated in 1917.

Circumstances being what they may ("don't you know there's a war on?"), both were fitted with directors in 1918.

The director was on a pedestal mounting without a tower. Likely, there was no directing gun.

In late 1917, at least, the ships had 6-in P. XIII Type Elevation Receivers with electrical tilt correction capable of indicating 15 degrees elevation, Pattern V.E. 3. Their Small Type Training Receivers were pattern number 22 on the 6-in gun #1, pattern number 23 on 6-in guns #2 and #3, pattern number 20 on the 4-in guns.

Dreyer Table

These ships probably had had no fire control tables during the war, but by 1930 each had Dreyer Turret Control Tables in her T.S..

Fire Control Instruments

In 1916, it was approved that the Calliope (and perhaps her class), should have range receivers in the fore top to show rangefinder ranges, presumably transmitted from the T.S.

By mid-1918, it had been approved to issue these ships, along with several other classes of light cruisers range repeat receivers for their fore bridge and control positions so that their captains and control officers could know the gun range.

Torpedo Control

Torpedo Control Circuits

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 C.T., and that a flexible voice pipe be fitted between these positions.

Additionally, in 1916, Birkenhead and Calliope classes were being fitted with Chadburn's Torpedo Telegraphs for torpedo order and gyro angle with one transmitter in the fore bridge position and one in the after position, operating separate instruments in the submerged torpedo flat. A mechanical reply was provided.

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, Technical History Section (1920). The Technical History and Index: Alteration in Armaments of H.M. Ships during the War. Vol. 4, Part 34. C.B. 1515 (34) now O.U. 6171/20. At The National Archives, Kew, United Kingdom.
• H.M.S. Vernon. (Jan 1916) Annual Report of the Torpedo School, 1915. C.B. 1166. Copy 1025 at The National Archives. ADM 189/35.
• 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.