The basic anchoring technique is to use a single anchor. However, special circumstances exist in which additional anchors may be used or solutions have previously been established.
A Mediterranean moor is setting the anchor from the bow, reversing, and then docking stern to a berth. The anchors should be dropped well out from the pier while at a Mediterranean moor to permit the ship to maneuver in the stream while weighing anchors, and the anchor chain should be kept moderately taut to prevent damage to the stern in the event of a headwind.
Mooring with two bow anchors has an advantage over anchoring with one bow anchor in that the radius of the vessel’s swing will be greatly shortened. The best way to lay out two anchors is to have them so that their lines form an angle with the scope being equal.
This will reduce the yaw of the vessel. The disadvantage is if the current flows from the opposite direction, forcing the vessel to swing, you may end with a fouled or crossed hawse in which your anchor cables become twisted.
In this, the ship’s boats can be sent off carrying the ship’s kedge anchors, which are one size down from the larger primary anchors used on the bow, which are the bower anchors. Once set, the kedge anchor would be hauled back until the vessel lay nearly atop it, and the second kedge anchor would be sent out and the process repeated.
This has practical modern applications. If a vessel is grounded with an outgoing tide it is judicious to set an anchor in deeper water to prevent the ship from being washed higher ashore. When the tide comes back in this anchor can be tensioned to help float the ship free into deeper water.
The first thing that you should do after the anchor has been let go is to take bearings of fixed objects onshore to obtain ship’s position and plot the vessel’s position on the chart. This position should be referenced throughout the watch and verified.
A precaution that can be taken is dropping a lead line over the side of the vessel, referred to here as a drift lead. If the drift lead line tends forward and is taut it is an indication of dragging anchor. Another indication of dragging anchor is the anchor able coming taut then slacking again. This is the anchor skipping over the seabed.
Vessels do not always scribe a perfect arc around the anchor with the changing of the tide. Depending on the vessel design and the weather conditions, the ship may be more greatly affected by the tide or by the wind. A vessel is tide rode when it is at anchor and stemming the current and is wind rode when it is at anchor and heading into the wind. This is why in an anchorage vessels may be facing different directions.
Veering out more chain is typically the best initial response to a dragging anchor. Increasing the scope will improve holding. If you run out of chain, or determine the anchor is tripped, fouled, or shod with clay, then the only recourse is to set a second anchor and recover the first or haul back and abandon the anchorage.
The use of an anchor to assist in turning in restricted waters is good seamanship. When using the anchor to steady the bow while approaching a dock you must be aware of the fact that using an offshore anchor decreases the chances of the anchor holding, due to the directions of force.
When you are using the anchor to steady the bow while maneuvering you have the proper scope of anchor cable when the bow is held in position with the engines coming slowly ahead; typically 1½ to 2 times the depth of the water. You would NOT do this if there is shallow water en route to the berth.
If you lose propulsion along a channel, you must use one or both anchors to maintain control of the vessel. Have your deckhands lower one or both anchors with a scope of twice the depth before setting the brake.