Nelson class battleship

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Nelson class Battleship
HMS Nelson in 1945
Class Overview
Type:	Battleship
Name:	Nelson
Number of ships:	Two ordered and commissioned
Preceded by:	Revenge-class
Succeeded by:	King George V-class
General characteristics
Displacement:	33,950 tonnes / 38,000 full load
Length:	710 ft (216.5 m)
Beam:	106 ft (32.3 m)
Draught:	33 ft (10 m)
Propulsion:	Two Brown-Curtis geared turbines; two screws
Speed:	23.8 knots
Protection:	Belt: 14 inches (356 mm) Deck: 6 inches (152 mm) 16 inch turret front 16 in. (406 mm) C turret: 18 in (457 mm) Turret sides: 9 in. (229 mm) Barbettes: 15 in. (381 mm) 6 inch turrets: 1.5 in. (38 mm) Citadel: 13.4 in. (330 mm)
Complement:	1,361 officers and enlisted
Armament:	9 × 16 inch (406 mm) /45 guns 12 × 6 inch (152 mm) guns 6 × 4.7 inch (119 mm) AA guns 14 × Bofors 40 mm AA 48 × 2 pdr (40 mm) pom-pom in multiple mounts 61 × 20 mm AA 2 × 24.5 inch (622 mm) torpedo tubes

For the Battleship class in the Cosmic Era of Gundam, see Nelson class battleship (Gundam)

The Nelson class were battleships of the British Royal Navy built shortly after the Washington Naval Treaty in 1922. They were the first British battleships built since the Revenge class of 1913, and the last until the King George V class of 1936. Because of the limitations of the treaty the structure of the ships had to be revised, which resulted in unusual design considerations.

Two ships of the class were produced, named after famous British admirals: HMS Rodney after George Brydges Rodney, 1st Baron Rodney of the Battle of Cape St. Vincent and Nelson after Horatio Nelson, 1st Viscount Nelson of the Battles of the Nile and Trafalgar.

[edit] History and design

The Battle of Jutland had shown the value of firepower and protection over speed and manoeuverability. Admiral Fisher's dictum that "speed is armour" had been tested in battle, and had been disproved in the context of the battle line for all their success at the battle of the Falklands. Thickness of armour and weight of shell were now seen as the keys to naval victory.

The next generation of British warships were to incorporate this lesson. After World War I, the Admiralty drew up plans for massive, heavily armoured battlecruisers and battleships, far larger and stronger than all previous vessels. The G3 battlecruisers would carry 16 inch (406 mm) guns, and the proposed N3 battleships would carry nine 18 in (457 mm) guns, and would be the most powerful vessels afloat. The Royal Navy would hold its superiority in the burgeoning arms race, despite the large warships planned in Japan and the US.

However, development was abruptly halted when the arms race was brought to a halt by the signature of the Washington Naval Treaty in 1922. Four battlecruisers were ordered but not actually laid down - some of the material acquired was used in Nelson and Rodney.

The Treaty limited all nations battleships to 35,000 tons and 16 in guns. This killed both the "battlecruisers" and projected super-battleships, and the Royal Navy was forced to scale down its designs.

They took aspects of the G3 and N3 designs - forward armament and blocky armoured superstructures - and liberal advantage of the text of the Treaty. The British had successfully ensured that the definition of maximum tonnage excluded fuel and boiler water. They had argued that policing the widespread British Empire meant their ships had to carry more of both and they should not be penalised against nations like the US that operated much closer to their naval bases. As a result water-filled anti-torpedo protection could be incorporated, contributing only its "dry" weight to the overall limit.

The result of this compromise was the Nelson class of battleships. These were well-armed and defended (nine 16 inch guns in three turrets), but light and small enough to conform to the Treaty terms. (Navy men referred to this as the "Cherry Tree Class", because it had been "cut down by Washington").

The limitations of the treaty against the need to increase firepower and armour, while keeping weight low, resulted in a radical new warship design. In order to reduce weight of armour, all the primary gun turrets were mounted on the foredeck, which shortened the necessary armored length. The G3 and N3 designs had put the gun turrets forward: two on the foredeck, one superimposed above the other, with the third between the bridge and stern structures. For the Nelsons all three could not be staggered in height, so No. 3 was level with No. 1 but behind and lower than No 2 and its angle of fire was obscured ahead and astern.

The secondary guns were all located near the stern - another element of the G3 design. The engines and superstructure were also placed aft. The boilers were placed aft of the engines in order to keep the funnel, and smoke, as far away from the bridge as possible and to allow the maximum protection against torpedo attack to the more voluminous turbine rooms.

Armour weight was also saved by using an internal, inclined armour belt. Inclined armour increases the effective thickness of the belt, and its internal disposition was intended to provide a low-resistance path to vent torpedo explosions out of the ship via displaceable plates (this feature was unsuccessful). The external hull of the ship was unarmoured: the outer plating was meant to initiate detonation of shells which would then explode outside the armour. Also, for the first time a British dreadnought was given thick decks to protect against plunging shells and aircraft-dropped bombs.

As a compromise design, unsurprisingly it had some serious flaws. The rear location of the superstructure caused maneuverability problems in high wind: the superstructure acted as a sail, causing the ships to "weathervane" when steaming at low speeds. This was a particularly dangerous problem in crowded harbours, and the ships were notoriously difficult to dock and embark. They were also difficult to turn, and hard to steer when steaming astern. This is attributable to having twin screws and single centre rudder which was out of the propeller race. However at sea (and at speed?) they were reported to handle well.

The inclined armour disposition increased the danger of shells diving under the armour belt. With wave motion along the side of the ship, with the ship rolling, or with a list caused by damage, the ship would have been at risk of shells passing almost unhindered into the vitals of the ship. In publicly-released information, the Admiralty always showed the inclined armour to be much deeper than was actually the case. They were not the only ships to suffer from this defect.

These ships were very different from the rest of the British battle fleet. Their main armament of 16"/45 guns were mounted in triple turrets, the only RN battleships to do so. The guns themselves where a step away from standard British designs. Where previous RN weapons fired heavy shell at a low velocity, the Nelson class followed the German practice of a lighter shell at a higher velocity. This change in policy was due to British post-war tests of the German equipment, although subsequent testing proved contradictory and these weapons were never considered to be as successful as the previous 15"/42. The guns suffered considerable barrel wear and had a large dispersion pattern. As a result their muzzle velocities were lowered which reduced their penetrative power. A heavier shell was needed but the cost of producing new shells and modifying shell handling and storage equipment had come at a time when RN funding had been heavily reduced, and so they had to make do.

The need to reduce weight and the use of triple mount turrets led to problems with the ammunition handling and loading machinery. Incorporating many safety features but using lighter materials meant there were complex but relatively fragile equipment that gave problems that had to sorted out over the ships' lifetime.

Finally, the blast of the guns firing disrupted officers on the bridge to such an extent that the guns were usually prohibited from firing abaft of the beam. A great deal of effort was expended in correcting this problem, and no solution was ever found. They even placed tempered glass in the bridge window holes, but firing the guns shattered them and filled the bridge with flying debris. Weight-saving measures had included the use of light materials such as aluminium for fittings and fir instead of teak for deck planking. These were far more susceptible to the effects of the main armament firing and caused more maintenance work.

[edit] The Ships

Because of their unusual silhouette, HMS Nelson and her sister Rodney were sarcastically nicknamed Nelsol and Rodnol by the Royal Navy - their maneuverability problems and silhouettes reminded Navy men of oil tankers, not battleships. (A series of fleet oilers had been built during the First World War that bore names ending in "ol".)

The large superstructure, which was triangular in plan, was sometimes referred to as the "Queen Anne's Mansions", from its similarity to a 14-storey brick residential development of the same name, opposite St. James' Park Station in London.

The closeness of the primary turrets to each other was also a danger to the structural integrity of the ships. The crews were warned to never fire all the 16 inch (406 mm) guns at the same time, because this would damage the deck - clearly, a serious handicap on a fighting ship. This is a long-standing rumour, and was disproved at the final action with the German battleship Bismarck, where Rodney did fire the occasional full broadside without any adverse effect. In fact the problem had only affected the ships during their early careers when the wooden deck was of insufficient thickness to resist the blast. A thicker deck of teak fitted in the later 1920s proved able to resist the forces.

Another complication was the size of the forward gun deck. This area had to be kept clear of obstructions since any structures located there would be destroyed by the blast of the guns. However, this left a very large area of the deck where anti-aircraft guns could not be sited. The problem was partially solved by mounting AA guns on top of the turrets, though air defence remained a serious weakness with these vessels throughout their careers.

In theory, the "all-forward" design reduced the danger of an enemy "crossing the T" of the ship. However, this advantage was offset by the awkward location of the third ("C") turret. For structural reasons it was mounted lower on deck than the second ("B"), which severely limited its forward field of fire. This was bad enough, but "C" could also not fire in the aft quarters without damaging the superstructure. (The bridge was a particularly unpleasant place to be when firing on distant stern targets.)

When the Washington Treaty lapsed in 1936, the Royal Navy abandoned the "all-forward" arrangement and returned to traditional designs with the King George V class.

Despite these difficulties, both Nelson and Rodney had successful careers during World War II, the latter vessel helping to sink the Bismarck in 1941.

[edit] References

• Siegfried Breyer, Battleships and Battlecruisers 1905-1970 (Doubleday and Company; Garden City, New York, 1973) (originally published in German as Schlachtschiffe und Schlachtkreuzer 1905-1970, J.F. Lehmanns, Verlag, Munchen, 1970). Contains various line drawings of the ships in various configurations.
• Robert Gardiner, ed., Conway’s All the World’s Fighting Ships 1922 - 1946 (Conway Maritime Press, London, 1980)

Nelson-class battleship

Nelson | Rodney

Preceded by: N3 class (planned) - Followed by: King George V class

List of battleships of the Royal Navy