Torpedo nets

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Torpedo nets were a passive naval warship defensive device against torpedoes, whose use was common practice from the 1890s through World War I. Torpedo nets were superseded by the anti-torpedo bulge and torpedo belts.

1 Origins
2 Design and use
3 Decline
4 See also
5 References

[edit] Origins

Following the introduction of the Whitehead torpedo, in 1873 and later the development of the torpedo boat, new means were sought to protect capital ships against attack by this new weapon. In 1876 the British Admiralty Torpedo Committee came up with a number of recommendations for combatting torpedoes, which included "... nets of galvanised iron hung around each battleship from projecting 40ft spars" ^[1]. Experiments were conducted in 1877 with HMS Thunderer becoming the first operational ship to be fitted with the nets.

The early nets were referred to as the "Bullivant type" after the London-based company that produced them. They were constructed from six and a half inch diameter (150 mm) steel hoops linked by smaller hoops to form a mesh, with a weight of approximately one pound per square foot (5 kg/m²). These were projected out from the sides of the ship on forty foot long (12 m) wooden poles. Extensive tests were conducted, with the nets proving capable of stopping the contemporary 14 inch (350 mm) diameter torpedo without being damaged. A 16 inch torpedo with a 91 pound warhead (41 kg) proved capable of causing limited damage to the net.

A heavier net was introduced in 1894 with consisting of two and a half inch (63 mm) hoops with a weight of five pounds per square foot (25 kg/m²).

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".

[edit] Design and use

In addition to new tactical measures (e.g., greater harbor 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 favored solution. These were heavy steel 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.

[edit] Decline

The sinking by torpedo of three Allied battleships during the 1915 Dardenelles Campaign, 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 as a ship defense when underway were largely abandoned after the 1916 Battle of Jutland in World War I. This battle showed that the nets could get tangled in the propeller when damaged by naval gunfire.

Torpedo nets were superseded by the anti-torpedo bulge and torpedo belts.

However, torpedo nets continued in use through World War II to protect ships at anchor, especially as obstacles against submarines, human torpedos, and frogmen. They were also used to protect dams, and led to the development of bouncing bombs to defeat them, as in Operation Chastise.