Anchorage selection. Preparation of a vessel for lying at anchor
The choice of a place of anchoring is defined by its purposes, duration, hydrometeorological conditions and a condition of the vessel.
In the inner roadstead anchoring is carried out in strictly certain place under the instruction of the pilot or according to rules of port and it is not represented to the navigator to choice a place of anchoring.
Places of anchoring in the outer roadsteads of large ports are usually charted. In this case the duty of the navigator is reduced only to choice a place of dropping anchor on specified anchoring place which should be made in view of free water area of roadstead and possible changes of vessel’s positions in case of change of direction and wind or current force.
Considerably wider requirements to choice anchoring place should be showed when anchoring is made for a long sediment in the big roadsteads or in separate bays.
Such anchoring should settle down in the places whenever possible closed from prevailing winds and currents, to be safe in the navigating attitude. The special attention should be given for nature of a ground and a bottom’s relief.
The greatest holding ability has clay. However at long parking it is possible anchor locking and a part of an anchor chain lying on a ground that will create significant difficulties of weighing anchor. Therefore optimum for anchoring are considered grounds are oozy, silt with sand which possess satisfactory holding ability and where anchors attach well. The sandy ground, gravel hold anchors worse. Anchors in such grounds can smoothly creep, that does not allow finding out drift of a vessel at once.
Anchoring on a stony or shelly ground is extremely undesirable. On such grounds holding capacity will be equal only to its weight and weight of the chain laying on a ground. Besides on a stony ground the anchor can get in a crevice that will result or in loss of an anchor and a part of an anchor chain, or at the best will make shooting from an anchor very difficult and long. The flat and equal bottom is always better, than with sharply varying depths.
Expected anchoring place should be closely investigated using port’s rules and charts. Using charts of the largest scale, it is necessary mark most convenient in the navigating attitude approaching ways, to mark on chart existing dangers, to take off from a chart marking dangers bearings and distances, to choose the most convenient reference points which would serve for the course control during approaching anchoring place.
At the approach to a place of anchoring it is necessary to transfer the main engine to work in a maneuverable mode, to check up work of machine telegraph and communication of an engine room with the bridge, to verify indications of ship hours on the bridge and in an engine room, to warn the watch in an engine room about expected time of anchoring.
Directly before of anchoring the work of windlass and the position of anchor chain in chain locker are checked.
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