Schwojen
Schwojen (also: schwoien ) refers to the turning of a ship to and fro in the wind at anchor or at an anchor buoy .
A ship at anchor is not fixed at a certain point, but moves within an arc around the anchor due to changes in the wind and / or current direction. Also, a ship is not always exactly leeward of its anchor. Depending on its hull shape and all superstructures, it can happen that a ship swings back and forth over a wide area: As soon as the ship is not exactly in the wind, its bow is pushed to leeward and the ship is slightly inclined to the wind. This pushes the ship leeward until the side pull of the anchor line is sufficient to pull the bow over to the other side. The ship begins to move to the other side until the other turning point is reached there in a similar way and the game begins again. The ship moves almost a third of a circle around the anchor even with a constant wind direction.
The size of the Schwoje circle depends on the length of the anchor chain and the wind and current conditions. The distance from the anchor to the ship is therefore by no means fixed - an increase in wind or electricity increases the tension on the anchor line or chain, which stretches as a result. On roadsteads and anchorages is therefore to ensure that adequate room between the ships, also because the ships do not necessarily move simultaneously to the same side. Particularly in areas where, in addition to the wind, the ships are also moved by electricity, particular care must be taken to ensure sufficient distance. Because of their deep and slender lateral plan , sailing ships tend to turn in the direction of the current, while motor boats with their high superstructures and catamarans, because of their small lateral plan, tend to orient themselves more towards the wind. So if sailing and motor boats are close to each other at the same anchorage, then they can orientate themselves very differently with changing wind and current conditions.
This is especially true in waters that are exposed to the tidal currents . Here a single anchor can break out particularly easily due to the change in the direction of flow and the ship can drift away. This can be counteracted by Vermuren . The ship is moored with a second anchor opposite the first. The Vermuren also reduces the Schwojkreis considerably.
literature
- Seamanship. Yachting manual. 30th edition, Delius Klasing Verlag , Bielefeld 2013, ISBN 978-3-7688-3248-9 .
