Torpedo nets
Encyclopedia
Torpedo nets were a passive naval warship
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...

 defensive device against 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. Their use was common practice from the 1890s through 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 Torpedo nets were superseded by the anti-torpedo bulge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:...

 and torpedo belt
Torpedo belt
The torpedo belt was part of the armouring scheme in some warships 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...

s.

Origins

With the introduction of the Whitehead torpedo
Robert Whitehead
Robert Whitehead was an English engineer. He developed the first effective self-propelled naval torpedo. His company, located in the Austrian naval centre in Fiume, was the world leader in torpedo development and production up to the First World War.- Early life:He was born the son of a...

 in 1873, and the subsequent development of the torpedo boat
Torpedo boat
A torpedo boat is a relatively small and fast naval vessel designed to carry torpedoes into battle. The first designs rammed enemy ships with explosive spar torpedoes, and later designs launched self-propelled Whitehead torpedoes. They were created to counter battleships and other large, slow and...

, new means were sought to protect capital ship
Capital ship
The capital ships of a navy are its most important warships; they generally possess the heaviest firepower and armor and are traditionally much larger than other naval vessels...

s against these underwater attacks. In 1876 the British Admiralty Torpedo Committee came up with a number of recommendations for combating torpedoes, which included "... nets of galvanised iron hung around each battleship from projecting 40ft spars" . Experiments were conducted in 1877, with HMS Thunderer
HMS Thunderer (1872)
HMS Thunderer was a British Royal Navy Devastation-class battleship.Thunder was an ironclad turret ship designed by Edward James Reed with revolving turrets, launched in 1872...

 becoming the first operational ship to be fitted with the nets.

Early nets were referred to as the "Bullivant type" after the London-based company that produced them. They were constructed from 6+1/2 in steel hoops linked by smaller hoops to form a mesh, with an approximate weight of one pound per square foot (5 kg/m²). These nets were projected out from the sides of the ship on 40 feet (12.2 m) wooden poles. Extensive tests were conducted, with the nets proving capable of stopping the contemporary 14 inches (355.6 mm) torpedo without being damaged. A 16 inches (406.4 mm) torpedo with a 91 pounds (41.3 kg) warhead proved capable of causing limited damage to the net.

A heavier net was introduced in 1894 consisting of 2+1/2 in hoops with a weight of five pounds per square foot (25 kg/m²).

Torpedo net cutter

The adoption of these nets resulted in the introduction of the torpedo net cutter on the nose of torpedoes,
either in the form of scissors in Japanese designs, or a French pistol-powered version.

Later heavier, denser nets used by the German and British navies were regarded as "torpedo-proof".

Design and use

In addition to new tactical measures (e.g., greater harbor
Harbor
A harbor or harbour , or haven, is a place where ships, boats, and barges can seek shelter from stormy weather, or else are stored for future use. Harbors can be natural or artificial...

 security and rotation of moored vessels out to sea), beginning in 1904 major navies sought a device for protection against torpedo boat attack.

Torpedo nets were the favoured solution. These were heavy steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 mesh nets that could be hung out from the defending ship, when moored or otherwise stationary in the water, on multiple horizontal steel booms. Each boom was fixed to the ship at one end at or below the edge of the main deck, by a steel pin that permitted the boom to be swung against the ship and secured when the ship sailed. A series of such booms were so fixed at intervals along each side of the ship. When the ship was moored, the free ends of the booms could be swung out with the net hung on the outer ends, thus suspending the net at a distance from the ship equal to the length of the boom, all around the ship. With the net mounted, a torpedo aimed at the ship would hit the mesh net and explode at a sufficient distance from the hull to prevent serious damage to the ship.

Russo-Japanese War 1904-1905

The first major use of torpedo nets was during the destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

 torpedo attack on the Imperial Russian Navy
Imperial Russian Navy
The Imperial Russian Navy refers to the Tsarist fleets prior to the February Revolution.-First Romanovs:Under Tsar Mikhail Feodorovich, construction of the first three-masted ship, actually built within Russia, was completed in 1636. It was built in Balakhna by Danish shipbuilders from Holstein...

 (IRN) stationed at Port Arthur on 08 February 1904; these were the opening shots of the Russo-Japanese War
Russo-Japanese War
The Russo-Japanese War was "the first great war of the 20th century." It grew out of rival imperial ambitions of the Russian Empire and Japanese Empire over Manchuria and Korea...

, conducted by the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...

 (IJN). Although it was a surprise attack, Russian naval intelligence had somewhat prepared for such an attack by conducting naval maneuvers, in which Russian destroyers practiced attacks against their battleships, however, the IRN didn't know when that attack would actually come. Consequently, the IJN had planned on the IRN battleships to have had their torpedo nets deployed when they launched their attack, and ordered "net cutters" to be attached to their torpedoes.

IJN destroyer captains had used net cutters during maneuvers and considered that net cutters were ineffective and caused stability problems for their torpedoes. Regardless, the order was given to install them, and the destroyers were to close onto their targets (the Russian battleships) at maximum speed before launching their "yellow cigars" at a range of about 200 meters.

During the actual attack on 08 February, three of the four destroyers planted their torpedoes into the waiting torpedo nets, as none of the net cutters had worked. Destroyer captains reported seeing "bubbles rising from the water alongside the net which held the torpedoes firmly suspended by their heads." The primary targets, the cruiser Pallada
Russian cruiser Pallada (1899)
The RUS Pallada was the lead ship in the of protected cruisers in the Imperial Russian Navy. It was built in Admiralty Shipyard, Saint Petersburg, Russia...

and the battleships Tsesarevich and Retvisan
Russian battleship Retvizan
Retvizan was a Russian pre-dreadnought battleship built before the Russo-Japanese War of 1904–05 for the Imperial Russian Navy in the United States. She was built by the William Cramp and Sons Ship & Engine Building Company of Philadelphia, although the armament was made at the Obukhov works in...

, received only moderate damage as the nets had protected their vital areas, leaving primarily their bows and stern sections unprotected. Destroyer captains reported that, if the Japanese net cutters had worked or the Russian nets had not been deployed, the Japanese torpedoes would have sunk all three Russian warships. After the attack, the IJN issued a new style net cutter, but it was already known that the Russian navy would not be caught by surprise again; and, if a ship was underway, it would not use torpedo nets.

During other actions later in the war nets were used effectively by the battleship Sevastopol
Russian battleship Sevastopol (1895)
Sevastopol was the last of three ships in the Petropavlovsk class of pre-dreadnought battleships built for the Imperial Russian Navy in the 1890s...

. At the end of the siege of Port Arthur, that vessel was anchored outside the harbor in a position where she was sheltered from the fire of the Japanese batteries but became exposed to persistent attacks from torpedo boats. From 11 to 16 December 1904, Sevastopol was exposed to numerous night attacks. The Japanese employed no less than 30 torpedo-boats, of which two were lost, and it was estimated that altogether 104 torpedoes were fired against the ship. One torpedo exploded in the nets near the bow and produced a leak in the torpedo room; another damaged the compartment forward of the collision bulkhead, because the nets yielded to such an extent that the explosion took place near the hull. The last two torpedoes that struck the ship were fired at close range against the unprotected stern: they damaged the rudder and produced a serious leak under the quarterdeck, so that the aft end of the ship sank until it touched the bottom. The leak was repaired. The ship again floated and on the last day of the siege she was taken out to deep water and sunk.

Decline

The sinking by torpedo of three Allied
Allies of World War I
The Entente Powers were the countries at war with the Central Powers during World War I. The members of the Triple Entente were the United Kingdom, France, and the Russian Empire; Italy entered the war on their side in 1915...

 battleships during the 1915 Dardanelles Campaign
Naval operations in the Dardanelles Campaign
The naval operations in the Dardanelles Campaign of the First World War were mainly carried out by the Royal Navy with substantial support from the French and minor contributions from Russia and Australia. The Dardanelles Campaign began as a purely naval operation...

, all with torpedo nets deployed, demonstrated that the increased speed of newer torpedoes and the tactic of firing several torpedoes at the same location on the target had made the torpedo net ineffective.

Torpedo nets were superseded by 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:...

 and torpedo belt
Torpedo belt
The torpedo belt was part of the armouring scheme in some warships 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...

s.

However, torpedo nets continued in use during 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...

 to protect ships at anchor, especially as obstacles against submarines, human torpedo
Human torpedo
Human torpedoes or manned torpedoes are a type of rideable submarine used as secret naval weapons in World War II. The basic design is still in use today; they are a type of diver propulsion vehicle....

es, and frogmen
Anti-frogman techniques
Anti-frogman techniques are security methods developed to protect watercraft, ports and installations, and other sensitive resources both in or nearby vulnerable waterways from potential threats or intrusions by frogmen or other divers....

. They were also used to protect dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

s, and led to the development of bouncing bomb
Bouncing bomb
A bouncing bomb is a bomb designed specifically to bounce to a target across water in a calculated manner, in order to avoid obstacles such as torpedo nets, and to allow both the bomb's speed on arrival at the target and the timing of its detonation to be pre-determined...

s to defeat them, as in Operation Chastise
Operation Chastise
Operation Chastise was an attack on German dams carried out on 16–17 May 1943 by Royal Air Force No. 617 Squadron, subsequently known as the "Dambusters", using a specially developed "bouncing bomb" invented and developed by Barnes Wallis...

.
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