Cattling

This article or the following section is not adequately provided with supporting documents ( e.g. individual evidence ). Information without sufficient evidence could be removed soon. Please help Wikipedia by researching the information and including good evidence.

So much criticism of a process found in all textbooks urgently needs a source

As a nautical term, kattening describes a special arrangement of the anchor gear . The procedure is often mentioned in the specialist literature and taught in sailing schools, but is of at most theoretical value due to a lack of correct feasibility.

If the anchorage is poor or in a laying wall situation (anchoring off a coast with an onshore wind), there are ways to increase the holding power of the anchor gear.

Chatting here means attaching another (mostly smaller) anchor to the main anchor of the ship. The smaller anchor is dropped first and should be a little more than a water depth from the main anchor. Then the main anchor is dropped. Now the tensile force of the ship can be distributed on the one hand to both anchors, on the other hand the ship is still secured by the second if one anchor breaks.

Comment on the theory

In shipping practice, this method is ignored today and has probably never been used successfully, as handling an anchor chain with two anchors is problematic and only possible if the harness is light enough to be carried by hand. In addition, the goal of increased safety and holding force can hardly be achieved in practice, since the load is only distributed to both anchors when both anchors are pretensioned in the pulling direction and buried one behind the other. However, this is not the case with wind, currents and swell.

If there are two anchors in a row on a chain, usually only one will dig itself in, as the other becomes powerless and motionless at that moment and has to finish his own digging. The second cannot dig in until the first fails. This is extremely dangerous because in the current overload situation both anchors do not engage. It is uncertain whether, when and which anchor will dig in again. In addition, the chance of success is reduced by interaction. The first anchor cannot swing freely because the second one is dragged along in order to find a soft place to dig in, while the second one drags in the churned-up furrow of the first.

The use of a large and a small anchor worsens the security situation from the outset. It is unlikely that the secondary anchor that has not yet been buried will replace the main anchor that is currently failing. It is grossly negligent to hope that the main anchor, which has not yet been buried, will replace the second anchor, which is initially held, by spontaneous burial if it fails. In addition, if the chain fails, both anchors and probably also the ship are lost, unless you have another anchor gear lying around, which also holds better than the first.

Katten today

For the safe and long-term anchoring of floating objects such as light ships or drilling platforms, however, catenation is the usual method. Two identical modern plate anchors (Danforth, Bruce, Delta, etc.) weighing up to 100 tons are placed one behind the other on the seabed via a short connecting chain (approx. Five anchor lengths). Both anchors, monitored by divers or cameras, are pulled into the bottom with large tugs and simultaneously flushed in with pumps. Usually, the anchors are then several meters deep in the ground with pre-tensioning and develop up to fifty times greater holding force with a constant pulling direction than they would do as a single anchor lying on the ground with a slightly changing pulling direction. So it's worth the effort.

Seamanship

In the opinion of the circumnavigator Wolfgang Hausner , the clogging in the nautical specialist literature represents a kind of running gag, since no author can afford not to mention this virtuoso anchoring technique, to praise it as a high school and, for lack of practical experiences of success, to copy it from a previous author. The public would consider such a book incomplete and dubious. The same applies to the dimensioning recommendations for the anchor gear. Although a modern combination of 6 mm chain feed and 10 mm polyamide hawser is superior in all respects to a pair of 6 mm chain and 16 mm (corresponds to 2 inch circumference) natural fiber hawser from 1900 in all respects, the recommended rope strength has been constant since imperial times, but now with high-strength polyamide. No author wants to be accused of making uncertain recommendations or guessing that “a lot helps a lot”.

Practical two-anchor techniques, however, are:

• Vermuren : Two equivalent anchors are relatively far apart, the chains / cables are connected in the middle and attached to the ship together. Suitable for changing directions of pull and little space or steep ground.

• Warp anchor: A second, possibly smaller anchor is deployed approx. 60 ° to the side of the main anchor and then pulled so close that the ship no longer swings (oscillates) around the main anchor. The method is suitable for unsteady winds and currents around one main direction.

• Two anchors: Two equivalent anchors are deployed approx. 30 ° to the main load direction in such a way that both anchors essentially bear evenly and are only loaded asymmetrically in the case of wind shifters, but remain loaded. For a refreshing wind from a known direction.