The holding ground in designated anchorages is generally good and the cause of dragging is usually
passing squalls or persistent high winds, especially those blowing over the tide (or current), or
indeed a strong tide or current itself, especially when the vessel is riding to insufficient cable for
The problem is further exacerbated in crowded anchorages where sea room is at a premium, and such crowded anchorages are becoming more and more common, resulting in a possible reluctance of the Master to use an adequate cable length which would, if used, reduce the possibility of dragging.
It is good seamanship practice to have a cable length paid out equivalent to 5 times the depth of the water, however more cable should be paid out if adverse conditions are anticipated during the time the vessel is at anchor.
A vessel 80 metres in length would have a turning circle radius of approximately 27.5m x 5 + 80m = 1.2 cables when anchored in depth of water of 30 metres. (When drawn on the chart this turning circle must be drawn from the “let go anchor” position and not be from the “brought up to” position).
The notice period for the use of the main engines is critical when at anchor and Masters should very carefully evaluate the circumstances under which the vessel is anchored (expected weather, tide and current conditions and the proximity of other vessels within the anchorage) before stipulating their requirements. The safety of the vessel is paramount and should override all
We would like to take this opportunity to reiterate to our Members the importance of Master’s paying out sufficient anchor cable to reduce the chances of dragging anchor and maintaining a notice period for using the main engines suitable for the prevailing and expected conditions.
Once anchored, the position of other vessels in the vicinity should be recorded, preferably on the radar and a watch kept so that any movement of our Members’ vessels or others in the anchorage become readily apparent allowing for evasive action to be taken.
When at anchor, the anchor not in use must be ready for letting go, including taking the weight off the bar and consideration given to using this second anchor in the event of dragging.
The importance of obtaining current weather forecasts cannot be emphasised strongly enough so that necessary precautions can be taken as necessary if required.