VES system

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A VES system ( advance self-protection or advance self-protection system ) was a protection of their ships against magnetic mines developed by the German navy .

development

After the advent of mines with magnetic detonation attempts were made to either further magnetize or demagnetize the hulls of iron or steel ships. With the latter, attempts were made to reduce the ship's magnetism to such an extent that the mine’s magnetic detonator did not respond at all (MES = magnetic self-protection ). With the VES method, on the other hand, an attempt was made to move the ship's magnetic field so far in front of the bow that the detonator of the magnetic mine responded well in front of the ship, causing the mine to explode prematurely. For this purpose, one or more cable loops charged with electricity were placed around the outer skin of the ship's hull , which increased the magnetic field forwards, in width and in depth. In addition, especially in the case of barrier breakers , the ship was loaded in the front part with iron ballast , the so-called core stowage (not to be confused with protective stowage), which increased the magnetic field by about seven times.

In 1938, the Navy tested the VES system on the light cruiser Nürnberg . For this purpose, the ship's hull was wrapped around the fore , midships and aft with three vertical VES windings, which were magnetized with 300 kW. The test was successful: a German magnetic mine at a depth of 28 m detonated 50 m in front of the ship. After the beginning of the Second World War , the system was installed in particular on the naval lock breakers . When Great Britain used the first magnetic mines in April 1940, the Navy already had a barrier breaker with VES, the barrier breaker IV Oakland , which was put into service on September 30, 1939 , and had the others equipped with it immediately.

technology

The cable loop consisted of a 6 to 10 km long and 30 cm thick rubber- sheathed copper cable, which was mounted around the hull in a so-called round winding (also called straight winding or bar winding) transversely to the ship's longitudinal axis. At first it was laid in one length as a continuous winding, later on the so-called single winding was used, as this made it easier to locate the fault. For protection, the cables were covered with a wooden panel. To supply the system with electricity, a special electrical system, mostly diesel generators, with an output of 100 to 300 kW was installed.

The core stowage, which is also part of the VES system, consisted of 500 to 2,000 t of iron, which were mostly stowed in the form of scrap (hence scrap stowage) over a distance of 18 to 30 m in the front cargo hold . However, since this impaired the center of gravity and the ship's stability and also meant a considerable demand for raw materials, in 1942 a much more efficient tank stowage was used, which only required 250 to 600 t of scrap iron.

Further developments

When Great Britain started using a double-contact fuse from 1942, in which the first contact made the mine armed and only the second detonated it, the Navy responded with the so-called "Aptierungsanlage", a polarity reversal device (UPV) that changed the polarity of the current in the VES -Winding reversed every 8 to 10 s. This triggered the second contact far enough in front of the bow of the barrier breaker.

A further development was then the cross winding. The previous cable winding was split and the two cable loops were mounted in a cross shape on the forecastle. The protective distance in front of the bow was still a sufficient 40 m.

Targeted at lock breakers, Great Britain then introduced the very blunt “lock breaker mine”. It required the full magnetic field of the barrier breaker for ignition and therefore responded exactly under the PVC winding. Because of its insensitivity, it could not be removed by any other clearing means. The German answer to this was the additional winding, also known as the compensation winding, consisting of two windings connected against one another, which counteracted the VES field and reduced it accordingly. The disadvantage of a slight reduction in the clearance width compared to conventional magnetic mines was accepted.

Canona Antimagnetica

The Italian " Canona Antimagnetica " was initially used on small barrier breakers that were supposed to keep port entrances, estuaries and inland waterways mine-free . It consisted of two iron rods laid in a cross shape on the upper deck, weighing a total of 90 t, through which electricity flowed and which were alternately polarized. The positive experience with it and the advantages over the VES system (no core stowage, only mounted on deck, easier assembly and repair) ultimately led to the development of the slightly modified German cross pole device (KPG), later also called cross bar device.

Other systems

Other attempts to clear magnetic mines directly in the direction of travel were two swiveling magnetic bars at the bow, each weighing 100 t, the transverse dipole system (QD system) weighing 100 t, and an inclined core stowage (called angled core or inclined stowage) with a weight of 400 t, could not prevail for various reasons.

literature

  • The Second World War - on the front lines of the Kriegsmarine: The tasks of the barrier breakers in naval warfare. In: Gerhard Bracke: Service on famous and on particularly endangered ships. Books on Demand, 2008, ISBN 978-3-8370-6161-1 , pp. 137-138 ( limited preview in Google book search)
  • Peter Arndt: German barrier breakers 1914 - 1945; Construction - Equipment - Armament - Tasks - Use. 2nd edition, Bernard & Graefe, Bonn 2004, ISBN 3763762574 .