Anchoring and Anchor Watch
Anchoring is not a pause from navigation: the choice of chain to pay out, monitoring for dragging, and the anchor watch itself remain safety activities in their own right.
Operational Explanation
Anchoring requires a specific technical assessment: the type of seabed, depth, forecast weather/sea conditions and area traffic determine the choice of chain to pay out and the need for a more or less intensive anchor watch.
A common conceptual error is to consider anchoring a passive safety condition: in reality, dragging (the anchor no longer holding the seabed) can occur with little warning, especially in rapidly changing wind or current conditions, requiring active, continuous monitoring.
Regulatory Reference
No single convention is dedicated specifically to anchoring; good practice derives from SOLAS Chapter V (the general obligation of safe navigational conduct, including the anchoring phase) and from the Company's internal SMS procedures, often based on industry guidelines (e.g. the Nautical Institute, P&I Clubs).
Scope of Application
Every ship at anchor, whether in an open roadstead or in designated anchorage areas within or near a port.
Procedure / How to Complete It
- Assess the type of seabed, depth and forecast weather/sea conditions before choosing the anchoring position and the chain to pay out.
- Calculate the chain to pay out as a function of depth and forecast conditions, not according to a fixed generic rule alone.
- Verify the ship's position relative to the anchor immediately after anchoring and periodically throughout the stay.
- Establish an anchor watch with a monitoring frequency appropriate to conditions (more frequent as wind/current intensifies).
- Prepare a response plan in case dragging is detected, including possible starting of the main engine and informing the Master.
Practical Example
Example anchor watch: verifying the ship's position every 15 minutes via GPS and shore transits, with a pre-established dragging alarm threshold; in anticipation of intensifying wind, additional chain paid out and the main engine placed on standby for rapid starting.
Real Cases
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Chain paid out according to a fixed generic rule, without considering forecast weather/sea conditions | Insufficient anchor holding if conditions deteriorate | Calculate the chain to pay out as a function of the conditions forecast for the entire stay, not just those at the time of anchoring |
| Anchor watch with checks too infrequent or entrusted to inadequately briefed personnel | Dragging not detected in time to intervene | Adjust the frequency of checks to real conditions and adequately brief the watch personnel |
| No response plan prepared in case dragging is detected | Delayed response once dragging is actually detected | Always prepare a clear response plan, including rapid starting of the main engine |
PSC Observations
Operational Tips
- Never apply a fixed rule for the chain to pay out: always calculate it as a function of the weather/sea conditions forecast for the entire stay.
- Increase the frequency of anchor watch checks as soon as conditions begin to deteriorate, do not wait until dragging is already evident.
- Always prepare a clear response plan for dragging, including the lead time needed to start the main engine.
Checklist
- Seabed, depth and weather/sea conditions assessed before anchoring
- Chain paid out calculated as a function of forecast conditions
- Position verified immediately after anchoring
- Anchor watch established with a frequency appropriate to conditions
- Response plan for dragging prepared and known to the watch personnel