Correspondence – Contact Incidents in Anchorages

A major Charterer noticed an increase in the number of incidents involving contact between vessels at congested anchorage locations. They issued a Safety Alert Bulletin to draw the attention to this issue and share good practices / lessons learnt from various incidents.

Causal Factors:

  • Bridge team’s failure to correctly assess the strength and direction of the local tidal current & wind prior to arriving at, and during departure from, the anchorage.
  • Manoeuvring own vessel too close to vessel(s) already at anchor.
  • Lack of proper navigational watchkeeping practices whilst at anchor.
  • Swinging circle not plotted, or used as a monitoring tool, especially during the swinging of anchored vessels in different directions.
  • Lack of monitoring clearances from adjacent anchored vessels during change of tide.
  • Inadequate monitoring of prevailing weather and weather forecasts, such as local seasonal winds, thunderstorms, passing squalls, etc., leading to the dragging of the anchor.
  • Unavailability of vessel’s main propulsion for immediate use, when required.

Good Practice: 

  • Pre arrival / departure planning in detail (i.e. appraisal, planning, execution & monitoring) including contingency, and site-specific risk assessments.
  • Evaluation of the prevailing congestion status at the port’s designated anchorages. Identifying a suitable anchorage position, in consultation with Port Authorities / VTS, prior to entering the anchorage area. Whilst approaching an anchorage, avoid passing close ahead of other anchored vessels.
  • Evaluation of adequate length of anchor cable to pay out, with due consideration to the prevailing conditions, holding ground and sea depth.
Plotting of vessel’s swinging circle on GPS, paper chart and ECDIS, if available, to ensure that the vessel has adequate clearance to swing about the anchor. Once anchored, the actual swing pattern to be ascertained and ECDIS/Radar/GPS alarm limits adjusted if available. Swing tendencies of other vessels in immediate vicinity should also be monitored, especially at change of tidal streams.
  • Calculation and marking of tidal streams where applicable and in known areas for strong tidal effects.
  • Maintaining a robust anchor watch at all times, checking of vessel’s position at regular intervals.
  • Echo sounder and anemometer limit alarms, where fitted, to be re-adjusted after anchoring.
  • Monitoring of weather at all times and having an action plan available, in case of expected adverse weather, or finding that anchored vessel’s are swinging in different directions.
  • Inserting a visual marker on the windlass to indicate any instances of the brake slipping.
  • Maintaining vessel’s main engine in an appropriate state of readiness.
  • Use of BNWAS, if available whilst at anchor.
  • Clear standing instructions on calling the Master well in time, based on situations specific to that anchorage location.
  • Emergency contact list of local support services (such as pilot, tugs, etc.) to be available at all times.
  • Bridge Team Simulator training provided to deck officers and Masters that includes scenarios with weather changes, such as but not limited to:

–  Approaching & anchoring in congested anchorages

–  Dragging own anchor in congested anchorages.

–  Other anchored vessels dragging their anchor, or a maneuvering vessel drifting towards own vessel at anchor, which could result in a contact incident.

  • Vessel operator’s internal navigation audit to include an evaluation of best practices, whenever possible.