Clearing otter

The Räumotter (engl. Paravane also Otter reamer (ORG), or only Otter ) is a technical tool for the minesweeping and the mine clearance .

An original paravane is an underwater glider pulled by a ship over a towline, which in 1917 was equipped with an explosive charge as Type Q (or High Speed Submarine Sweep ). This explosive charge could be detonated by touch or from the towing ship via the tow cable. The construction was later simplified by eliminating the explosive device and adding a cutting tool to the slider. For use as a so-called Räumotter the slider could through the towline the anchor chains of sea mines ( moored mines capture), these slid on the tow line along to the cutting tool on the side or in the head region of the Räumotter and the anchor chain has been cut by this. The sea mine rose to the surface and could be defused there.

The underwater glider has a teardrop shape with a mostly passive tail unit at the stern and two lateral "wings" in the front area. To protect the clearing otter or to guide the anchor chain to the cutting tool, a guard bar could also be attached to the bow. The construction weighed around 480 kg in total.

history

A clearing otter on the deck of the USS Texas museum ship , 2014

The original design was by the English officer, inventor and later politician Dennistoun Burney 1917. Patent registered and found in the Royal Navy in the First World War application. The idea is given to the commander ; later Vice Admiral and Politician; Attributed to Cecil Usborne .

In October 1914, Burney submitted the first plans, in May 1915 a test phase started on a British destroyer and in August 1915 the construction was certified as having a satisfactory effect, so that widespread use of the various types of paravans in the Royal Navy was envisaged. From 1916 the more simplified Type M or Otter came into use. A total of at least 20 different types were designed for the Royal Navy, all of which were sorted with a type designation under the name Mark , such as. B. Type T, Mark I . During the First World War, different types were used in parallel and were characterized, among other things, by the different weights of the Paravane and thus the possible uses.

In the German language of the Kriegsmarine , the device is called a clearing otter or just an otter and was used on the minesweepers of the minesweeping flotilla. The naming is associated on the one hand with the body shape of an otter . Another derivation of the name refers to the so-called otter crane, which the clearing otter could bring out from the deck.

Insert form

The device was originally used for self-protection as a bow protection device on larger war or merchant ships, such as. B. the Centaur , used. Usually a paravane was used on both sides of the ship and could keep sea mines from detonating near the ship's side.

Paravans were also attached to the bow for mine hunting and clearing. In addition, the defense against submarines was carried out by deployed paravans. During the First World War, it was mainly destroyers who used the paravans for these two methods.

The paravane, equipped with explosives, was preferred against submarines. B. used in the British destroyers of the Acheron class . Drag lines with explosive charges or friction points were also used to separate the anchor chain earlier.

From 1929, paravans were also used as a rear-mounted device to search for and clear mines. This became the preferred application in World War II .

handling

Description of the use of a clearing otter, 1943

Depending on the use of the hot eyes / eyes of the clearing otter, it was possible to switch between port and starboard . On the discharge side, the clearing otter was lowered into the water by crane.

After the clearing otters are released, the wings pull them sideways away from the tug and thereby tension the towline. A track buoy could be used on the water surface to mark the position of the clearing otters. The clearing otter was able to maintain the depth automatically without a float over the length of the towline and an extra kite was no longer necessary. This meant that the clearing otter could be used more universally than the classic clearing gear. In most cases, a depth of 1.5 m below the maximum depth of the ship is kept. In addition to a tight towline, the towing angle must be kept at an obtuse angle to the ship's course. The usual speed when searching for mines is 9 knots .

If a sea mine was detected under water, the anchor chain of the mine touched the towline and the anchor chain runs along the towline to the clearing otter. At the end of the towline, the anchor chain goes into the cutting tool, which is attached to the clearing otter. The sea mine rises to the surface. If the anchor chain cannot be cut, the clearing otter is moved to the mine by the ship's movements and the mine is triggered by the clearing otter. A sea mine brought to the surface was z. B. blown up by gunfire.

literature

Description and operating instructions for the clearing otters: DV-453/4 . Naval Command, 1959.
The Year 1919 Illustrated: The Paravane . Stokes, 1919, p. 136 ff.

Web links

Commons : Paravane (weapon) - Collection of images, videos and audio files

Historical drawings of paravans and their use on Institution of Mechanical Engineers

Individual evidence

↑ ^a ^b ^c ^d Marine-Rundschau . 1940, p. 83 ( google.com [accessed August 4, 2020]).
↑ ^a ^b ^c ^d Reinhart Ostertag: German minesweepers: 80 years of anti-sea mine defense . Koehler, 1986, ISBN 978-3-7822-0394-4 , pp. 54 ( google.com [accessed August 4, 2020]).
^ Apparatus for offense or defense against submerged or partially submerged orstructions . US1358358A, 1917.
↑ ^a ^b ^c ^d Arthur Marder: From the Dreadnought to Scapa Flow: Volume II: To The Eve of Jutland 1914-1916 . Pen and Sword, 2014, ISBN 978-1-4738-2657-1 , pp. 73 ( google.com [accessed August 4, 2020]).
↑ ^a ^b ^c Arthur Marder: From the Dreadnought to Scapa Flow: Volume II: To The Eve of Jutland 1914-1916 . Pen and Sword, 2014, ISBN 978-1-4738-2657-1 , pp. 74 ( google.com [accessed August 4, 2020]).
^ ^A ^b ^c Hermann Franke: Handbook of the modern military sciences: Volume 1. The Navy. 2. The Air Force . W. de Gruyter & Company, 1938, p. 211 ( google.com [accessed August 4, 2020]).

[:0-1] Marine-Rundschau . 1940, p. 83 ( google.com [accessed August 4, 2020]).

[:3-2] Reinhart Ostertag: German minesweepers: 80 years of anti-sea mine defense . Koehler, 1986, ISBN 978-3-7822-0394-4 , pp. 54 ( google.com [accessed August 4, 2020]).

[3] Apparatus for offense or defense against submerged or partially submerged orstructions . US1358358A, 1917.

[:1-4] Arthur Marder: From the Dreadnought to Scapa Flow: Volume II: To The Eve of Jutland 1914-1916 . Pen and Sword, 2014, ISBN 978-1-4738-2657-1 , pp. 73 ( google.com [accessed August 4, 2020]).

[:2-5] Arthur Marder: From the Dreadnought to Scapa Flow: Volume II: To The Eve of Jutland 1914-1916 . Pen and Sword, 2014, ISBN 978-1-4738-2657-1 , pp. 74 ( google.com [accessed August 4, 2020]).

[:4-6] A ^b ^c Hermann Franke: Handbook of the modern military sciences: Volume 1. The Navy. 2. The Air Force . W. de Gruyter & Company, 1938, p. 211 ( google.com [accessed August 4, 2020]).