In our previous article we took time to highlight different what makes a merchant ship to drag its anchor. Now we are to focus on how to assess the vessel that is dragging its anchor.
To achieve this follow this steps: Inspect the ship’s position at regular intervals, to be sure if the vessel is going outside the swinging circle. Use all available methods, both visual and electronic materials like GPS, RADAR and ECDIS, to appraise the situation. If the vessel goes from the circle, it is likely that it is dragging its anchor
- The bow cannot stay against the wind
- Inspect anchor chains for slipping, a small pole with a cloth as flag like arrangement can be tied to the links to know the slipping of anchor chains
- Extra vibration and weight on anchor cable
- Inspect the speed over ground (SOG) while the vessel is swinging, the SOG can add variably and this should never be misinterpreted
- Inspect the course recorder for figure of eight motion locus
- Equally monitor the position and distance of vessels close by. In case there exist dragging counter methods to be taken to safe guard own vessel
What actions should you take if the vessel has begun dragging anchor?
- Master should be informed, never hesitate to call him at any time of the day, his experience and decision making authority is imperative in any give situation
- The engine room should be informed and start the main engine with the permission from the master and offer power to windlass if this has not already been given. Prepare vessel for manoeuvring
- Halt all cargo operations and get vessel ready for manoeuvring. Let go cargo barges and crane barges if they are alongside
- Tell and alert Vessel traffic system (VTS) and other vessels nearby about the condition and the about the actions taken. Request permission for re-anchoring
- Begin heaving up the anchor and the moment the vessel’s manoeuvrability is restored, shift the anchorage position where drifting can get safer or take to the open sea
- Deploy more of cable or drop a second anchor (not recommended for big vessels) before the speed of dragging of the vessel addsup. This can halt the small vessel from dragging anchor at a very early stage before the ship is put to leeward side with an increased speed
- Use bow thrusters, main engine and steering to manoeuvre. It gets harder to weigh anchor when the vessel is pressed more to the leeward side and takes considerable quantity of time. Use bow thrusters for stemming the wind. Do not override the anchor particularly in shallow waters as the vessel may impact on the anchor during pitching.
- If the scenario permits, let the vessel drag in a controlled manner. But this is not advised in places where offshore work such as oil and gas operations are being performed, that can result in damaging the submerged pipe lines, cables etc.
- Release the bitter end and let go of the anchor completely, when weighing of anchor is not possible. A ship without minimum of 2 anchors is not deemed to be sea worthy, a careful assessment is to be made before making this decision
- Call (tugs) for assistance. This gets possible only if the weather allows
Many accidents collision or grounding occurs while the vessel is at anchor largely because of no early prediction of dragging anchor. Time plays a major role in area of high vessel density and this time lapse leads to difficulty in restoring the manoeuvrability of the vessel. Make sure that the right contingency plan is put in place to control such incidents and avoid arising of any emergency because of dragging anchor.