Torpedo belt
Encyclopedia
The torpedo belt was part of the armouring scheme in some warship
s of between the 1920s and 1940s. It consisted of a series of lightly armoured compartments, extending laterally along a narrow belt that intersected the ship's waterline
. In theory, this belt would absorb the explosions from torpedo
es and thus minimize internal damage to the ship itself.
Torpedo belts are also known as Side Protection Systems or SPS, or Torpedo Defense System or TDS.
and heavy
cruisers) of the early 20th century carried their main protective armour above the waterline – the "main belt
" – which was intended to stop flat-trajectory gunfire from piercing the hull. Below the belt, the armour generally tapered away, to reduce overall weight. This, however, makes a ship vulnerable to hits below the waterline from torpedoes; and the occasional large-calibre shell. Extending the belt downwards is impractical, since this increases displacement, which increases draught and can result in reduced speed, and decreasing seaworthiness.
. Some ships were fitted with underwater armour in vulnerable areas below the waterline. This stopped torpedoes from penetrating the ship but the shock from an underwater explosion
s could cause damage to weapon mountings and sensitive machinery, along with violently stressing the ships' structure.
increased the urgency to devise an effective torpedo defense system (TDS, thus the British
Director of Naval Construction
introduced the anti-torpedo bulge
. Originally retrofitted to older ships, this was soon added to ships already under construction. In 1915 the British Renown-class
battlecruiser
s and in 1917 American Tennessee-class
battleships, introduced anti-torpedo bulges. Most later capital ships would have at least one torpedo bulkhead
inboard of the external hull plating along the area of the ship protected by the armour belt. Most Battleships built after World War I had sophisticated and complex side-protection systems, as illustrated by the cross sectional drawing of Tirpitz and King George V.
that curtailed ship weights and with the introduction of the British Nelson class
battleships, that a true layered torpedo belt was introduced. The two Nelsons used a water-filled belt, which was written off in the tonnage limits, as water was not part of the calculations for allowed displacement. Over the next 20 years many innovative designs of TDS were tried by various nations.
By the end of World War II
torpedo belts, much like many of the warships they protected, were rendered obsolete by the widespread use of aircraft, and guided missile
s which attacked above the belt and a new generation of "smart", deep-diving torpedoes (such as the Mark 48
) which are designed to detonate under a ship's keel
and break its back.
Warship
A warship is a ship that is built and primarily intended for combat. Warships are usually built in a completely different way from merchant ships. As well as being armed, warships are designed to withstand damage and are usually faster and more maneuvrable than merchant ships...
s of between the 1920s and 1940s. It consisted of a series of lightly armoured compartments, extending laterally along a narrow belt that intersected the ship's waterline
Waterline
The term "waterline" generally refers to the line where the hull of a ship meets the water surface. It is also the name of a special marking, also known as the national Load Line or Plimsoll Line, to be positioned amidships, that indicates the draft of the ship and the legal limit to which a ship...
. In theory, this belt would absorb the explosions from torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...
es and thus minimize internal damage to the ship itself.
Torpedo belts are also known as Side Protection Systems or SPS, or Torpedo Defense System or TDS.
The problem
Armoured warships (dreadnought battleships, armoured cruisers and later lightLight cruiser
A light cruiser is a type of small- or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck...
and heavy
Heavy cruiser
The heavy cruiser was a type of cruiser, a naval warship designed for long range, high speed and an armament of naval guns roughly 203mm calibre . The heavy cruiser can be seen as a lineage of ship design from 1915 until 1945, although the term 'heavy cruiser' only came into formal use in 1930...
cruisers) of the early 20th century carried their main protective armour above the waterline – the "main belt
Belt armor
Belt armor is a layer of heavy metal armor plated on to or within outer hulls of warships, typically on battleships, battlecruisers and cruisers, and on aircraft carriers converted from those types of ships....
" – which was intended to stop flat-trajectory gunfire from piercing the hull. Below the belt, the armour generally tapered away, to reduce overall weight. This, however, makes a ship vulnerable to hits below the waterline from torpedoes; and the occasional large-calibre shell. Extending the belt downwards is impractical, since this increases displacement, which increases draught and can result in reduced speed, and decreasing seaworthiness.
Solutions
Another solution was needed. Originally, torpedo nets were tried. These were heavy metal mesh nets hung out on booms at some distance from the sides of ships to catch or detonate torpedoes short of the ship. These proved largely ineffective against torpedoes, since they could only be deployed when ships stationary, were useless against shell hits below the waterline, and were ineffective against minesNaval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
. Some ships were fitted with underwater armour in vulnerable areas below the waterline. This stopped torpedoes from penetrating the ship but the shock from an underwater explosion
Underwater explosion
An underwater explosion, also known as an UNDEX, is an explosion beneath the surface of water. The type of explosion may be chemical or nuclear...
s could cause damage to weapon mountings and sensitive machinery, along with violently stressing the ships' structure.
Anti-torpedo bulges
The outbreak of World War IWorld War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
increased the urgency to devise an effective torpedo defense system (TDS, thus the British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
Director of Naval Construction
Director of Naval Construction
The Director of Naval Construction was a senior British civil servant post in the Admiralty, that part of the British Civil Service that oversaw the Royal Navy. The post existed from 1860 to 1966....
introduced the anti-torpedo bulge
Anti-torpedo bulge
The anti-torpedo bulge is a form of passive defence against naval torpedoes that featured in warship construction in the period between the First and Second World Wars.-Theory and form:...
. Originally retrofitted to older ships, this was soon added to ships already under construction. In 1915 the British Renown-class
Renown class battlecruiser
The Renown class consisted of a pair of battlecruisers built during the First World War for the Royal Navy. They were originally laid down as improved versions of the s. Their construction was suspended on the outbreak of war on the grounds they would not be ready in a timely manner...
battlecruiser
Battlecruiser
Battlecruisers were large capital ships built in the first half of the 20th century. They were developed in the first decade of the century as the successor to the armoured cruiser, but their evolution was more closely linked to that of the dreadnought battleship...
s and in 1917 American Tennessee-class
Tennessee class battleship
The Tennessee class was a class of battleships of the United States Navy. The class comprised two ships: and the . They were modified versions of the featuring improved underwater armor for better torpedo protection and 30 degree elevation on their main batteries, as opposed to 15 degrees for...
battleships, introduced anti-torpedo bulges. Most later capital ships would have at least one torpedo bulkhead
Torpedo bulkhead
A torpedo bulkhead is a type of armor common on the more heavily armored warships, especially battleships and battlecruisers of the early 20th century. It is designed to keep the ship afloat even if the hull was struck underneath the belt armor by a shell or by a torpedo...
inboard of the external hull plating along the area of the ship protected by the armour belt. Most Battleships built after World War I had sophisticated and complex side-protection systems, as illustrated by the cross sectional drawing of Tirpitz and King George V.
Torpedo belts
It was not until 1922, in the wake of the Washington Naval TreatyWashington Naval Treaty
The Washington Naval Treaty, also known as the Five-Power Treaty, was an attempt to cap and limit, and "prevent 'further' costly escalation" of the naval arms race that had begun after World War I between various International powers, each of which had significant naval fleets. The treaty was...
that curtailed ship weights and with the introduction of the British Nelson class
Nelson class battleship
The Nelson class was a class of two battleships of the British Royal Navy, built shortly after, and under the terms of, the Washington Naval Treaty of 1922...
battleships, that a true layered torpedo belt was introduced. The two Nelsons used a water-filled belt, which was written off in the tonnage limits, as water was not part of the calculations for allowed displacement. Over the next 20 years many innovative designs of TDS were tried by various nations.
By the end of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
torpedo belts, much like many of the warships they protected, were rendered obsolete by the widespread use of aircraft, and guided missile
Guided Missile
Guided Missile is a London based independent record label set up by Paul Kearney in 1994.Guided Missile has always focused on 'the underground', preferring to put out a steady flow of releases and developing the numerous GM events around London and beyond....
s which attacked above the belt and a new generation of "smart", deep-diving torpedoes (such as the Mark 48
Mark 48 torpedo
The Mark 48 and its improved ADCAP variant are heavyweight submarine-launched torpedoes. They were designed to sink fast, deep-diving nuclear-powered submarines and high-performance surface ships.-History:...
) which are designed to detonate under a ship's keel
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...
and break its back.