Lord Nelson Class Battleship (1906)

Overview of 2 vessels
Citations for this data available on individual ship pages
Name	Builder	Laid Down	Launched	Completed	Fate
Agamemnon	William Beardmore & Company	15 May, 1905	23 Jun, 1906	25 Jun, 1908	Sold 24 Jan, 1927
Lord Nelson	Palmer Shipbuilding and Iron Company, Jarrow	18 May, 1905	4 Sep, 1906	1 Dec, 1908	Sold 4 Jun, 1920

Binoculars

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

Armament

In early 1913, new pattern G. 329 trainer's telescopes of 2.5 power and 20 degree field were issued to these and many other capital ships, to replace the 5/12, 5/15 and 5/21 variable power G.S. telescopes that had previously been in use.

12-in Guns

This section is sourced in The Sight Manual, 1916.

The ten 12-in guns were Mark X mounted in B. VIII turrets. The mountings could elevate between 13.5 degrees and 5 degrees depression.

The gun sights were gear-worked sights with telescopes (periscopes would not debut until St. Vincent) with a range gearing constant of 32 and limited to 15 degrees elevation.

The deflection gearing constant was 82.66, with 1 knot equalling 2.40 arc minutes, calculated as 2700 fps at 5000 yards. Range drums were provided for full charge at 2650 fps, reduced charge at 2225 fps, as well as for 6-pdr sub-calibre guns and .303-in aiming rifles.

Muzzle velocity was corrected by adjustable pointer between +/- 75 fps. No explicit mention is made of temperature and C correctors, but they may have been identical to those in Dreadnought.

Drift was corrected by inclining the sight bracket by 2 degrees.

The side position sighting lines were 36.75 inches above and 41.35 inches abreast the bore, and the central scopes were 36.75 inches above and 42 inches abreast.

9.2-in Guns

This section is sourced in The Sight Manual, 1916, except as noted.

The ten 9.2-in guns Mark XI were arranged on the broadside in two single Mark VIII and four double Mark VII mountings able to elevate 15 degrees and depress 5 degrees. The turrets on each side were numbered 1-3, fore to aft, qualified by "port" or "starboard".

The sights (those in double turrets also used in Minotaur class) were gear-worked with a range gearing constant of 37.04 in the single turrets and 32 in the doubles, graduated to 15 degrees (likely 16,300 yards for 2 CRH projectiles). Range dials were provided for full charge at 2825 fps, reduced charge at 2425 fps, and 3-pdr sub-calibre and .303-in aiming rifle. MV was corrected by adjustable pointer to +/- 75 fps. The deflection was on a gearing constant of 78.12 in the single mount and 82.66 in the doubles, 1 knot being 2.49 arc minutes, calibrated for 2875 fps at 5000 yards for both.

Drift was corrected by inclining the sight carrier 1.5 degrees. Sighting lines were 12 inches above the bore and 42 inches to the side for the single mount. The double mounts had a side sighting position with sight lines 32.65 inches above the bore and 32 inches abreast whereas the central position was 38 inches abreast the bore.

A "C" corrector was fitted, presumably also a temperature corrector.

Other Guns

High velocity 12-pdr 18 cwt guns were mounted on P. IV* mountings, similar to those in the Minotaur, King Edward VII and Dreadnought classes.

The mounting could elevate to 20 degrees and depress to 10 degrees, but though its sight could match the 20 degree elevation, the range dial was only graduated to 14.5 degrees (7,900 yards). This was fine, as there was limited fire control support provided for them and the weapons proved to have little effectiveness at the ranges where torpedo attack became deeply worrying.

The gear-worked sights were similar to the P. IV type, but added a cross-connected trainer's sight. They had a range gearing contant of 54 and range dials for 2550 fps, 1962 fps, and 1-in and .303-in aiming rifles. The first series produced corrected for M.V. with detachable cams for 2600, 2575, 2550, 2525 and 2500 fps. The second series replaced these with an adjustable pointer for +/- 50 fps.

The deflection gearing constant was 63.38 with 1 knot equal to 2.96 arc minutes, corresponding to 2600 fps at 2000 yards. Drift was corrected by inclining the sight carrier arm 2 degrees.

The layer's and trainer's sight lines were 10 inches above the bore, and 10.25 inches abreast.

The sight lacked a "C" corrector. There do not seem to be temperature correctors or open sights.

Torpedoes

The ships carried five submerged 18-in tubes:

• two forward, depressed 1 degree and angled 10 degrees before the beam, axis of tube 11 feet below load water line and 2 foot 5 inches above the deck.
• two aft, depressed 1 degree and angled at 25 degrees abaft the beam; axis of tube 11 feet below load water line and 2 foot 5 inches above the deck.
• one in the stern, depressed 1 degree; axis of tube 7 feet below load water line and 1 foot 6 inches above the deck.

In 1909, it was decided that ships of this class were to carry 10 heater torpedoes, distributed with six in the forward submerged flat, two in the aft, and two at the stern tube. The goal, when supplies were made good, was to have the ten heaters be Mark VI* H. or Mark VI** H..

In 1913, it was approved as part of a general reallocation of 18-in torpedoes, to replace the torpedoes on these ships with Mark VI** H. or Mark VI*** H. torpedoes.

In early 1914, the ships had four Torpedo Director Pattern 2006s and were to have them exchanged for -A models which supported gyro angling.

Fire Control

The general system of wiring between the T.S.es is illustrated in Handbook for Fire Control Instruments, 1914.

Rangefinders

In 1918, as part of a general desire to add rangefinders for torpedo control, it was approved to add a 9-foot rangefinder on a fixed mounting at an unstated position.

Evershed Bearing Indicators

Installed by late 1914, these ships appear to have had but a single transmitter with all-around training, addressing the fore and aft turrets as receiving stations.

Gunnery Control

The ship's guns were organized in 3 groups:

1. Two 12-in turrets
2. Starboard 9.2-in turrets
3. Port 9.2-in turrets

Local Control in Turrets

There was no provision in these ships for local turret control wherein the receivers in the turret could be driven by transmitters in the officer's position at the back of the turret.

Directors

These ships never received directors for main or secondary batteries.

Transmitting Stations

These ships had fore and aft T.S.es.

A C.O.S. allowed control options of

1. Fore
2. After
3. Separate

Each control group had Barr and Stroud Mark II transmitters with a pair of receivers, one wired directly to the transmitter as a tell-tale, and the other fed off the wires going to the distant guns (i.e., the aft guns for the fore T.S. and vice-versa) as a repeat. "These repeat receivers are necessary to keep the idle transmitters in step; when changing back from separate control they are required to enable both halves of the group to be set alike before being paralleled on to one transmitter."

Dreyer Table

These ships never received Dreyer tables.

Fire Control Instruments

By late 1909, these ships were equipped with Barr and Stroud Mark II equipment for range, orders and deflection.

The Handbook for Fire Control Instruments, 1909 lists the Barr and Stroud Mark II equipment on this class as:

• Combined Range, Order, Deflection: 8 transmitters, 32 receivers
• Group Switches: 4
• Rate: 4 transmitters, 12 receivers

Additionally, this class had the following Graham fire control equipment:

• Turret fire gongs: 22 with 8 keys (pushes in lamp box; 16 keys in Lord Nelson)
• Fire Gongs: none
• Captain's Cease Fire Bells: 14 with 1 key

This was the first battleship class in the Royal Navy to have Target Visible and Gun Ready signals, with indications of which turret could see the target and which guns were ready being visible in the TSes and control positions.

See Also

• Wikipedia

Bibliography

• 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 (1914). Handbook for Fire Control Instruments, 1914. G. 01627/14. C.B. 1030. Copy 1235 at The National Archives. ADM 186/191.
• 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 (1918). Handbook of Captain F. C. Dreyer's Fire Control Tables, 1918. C.B. 1456. Copy No. 10 at Admiralty Library, Portsmouth, United Kingdom.