Module 3 - Anchorwork
Advanced Scenario Check: Backing Wind and Closing Escape
What you will learn
Interpret corroborated movement towards danger, calculate a time-to-hazard sense check and give the first defensible command without treating the arithmetic as safe waiting time.
A deteriorating anchorage becomes a command problem before it becomes a collision. The learner must separate normal swing from ground movement, quantify urgency, protect the crew and cable, and execute the already briefed fallback.
A fictional 11-metre yacht is anchored overnight in a crowded bay. The anchor was set and independently checked in settled conditions. At 0200 the wind backs and gusts across the entrance as the stream turns. The yacht now yaws towards a lee-shore hazard and a neighbouring vessel swings on a different arc.
The watchkeeper compares a shore transit, depth and two electronic ground positions. After allowing for the expected swing, those observations place the yacht 0.10 nautical mile closer to danger after six minutes. The remaining charted distance to the chosen danger boundary is 0.35 nautical mile. The original alarm radius is too broad to protect that new margin.
Convert six minutes to 0.1 hour. The observed closing rate is 0.10 nautical mile divided by 0.1 hour, which is 1.0 knot. At an unchanged 1.0 knot, 0.35 nautical mile would be covered in 0.35 hour, or 21 minutes. Recalculate independently: 21 minutes at 1.0 knot is 21 divided by 60, or 0.35 nautical mile.
Twenty-one minutes is not a safe waiting allowance. The rate can change, the danger boundary is not a collision prediction, and crew must be mustered before the yacht can be controlled and the cable recovered or released. The calculation is an urgency check that rules out delay; it is not an ETA to use up.
Give the first command as a coordinated sequence: alert and muster the required crew, ready or start propulsion when safe, establish helm and navigation control, keep people clear of the loaded cable and windlass, confirm cable and propeller separation, and execute the briefed departure, controlled re-anchor or assistance plan. If safe recovery cannot be achieved inside the remaining margin, preserve the vessel and people through the planned release or abandonment method rather than forcing the gear.
Continue navigating after the anchor no longer provides control. Maintain a proper lookout, display or sound the signals required by the vessel's actual status, communicate early when assistance is needed and do not let the foredeck task obscure the lee shore, traffic or escape route. The exact engine, helm, cable and distress actions remain vessel- and situation-specific.
Worked example
Use the observations to decide whether the crew can wait for another alarm cycle.
- 1Evidence: the visual transit, depth and two ground positions agree that the change is progressive movement, not only normal swing.
- 2Elapsed time: 6 minutes divided by 60 equals 0.1 hour.
- 3Observed closing rate: 0.10 nautical mile divided by 0.1 hour equals 1.0 knot.
- 4Nominal time to the 0.35-nautical-mile boundary: 0.35 divided by 1.0 equals 0.35 hour; 0.35 multiplied by 60 equals 21 minutes.
- 5Independent sense check: 21 minutes at 1.0 nautical mile per hour covers 21/60, or 0.35 nautical mile.
- 6Decision: do not wait. The rate may accelerate and the crew, propulsion, cable and route require time. Execute the already briefed fallback now while control remains possible.
Sense check: If the learner calls 21 minutes 'time available', the calculation has been misused. It is a nominal closing time under an unsafe constant-rate assumption, before manoeuvring and safety margins.
| Evidence | Command consequence |
|---|---|
| Transit, depth and ground positions agree | Treat the movement as real; do not let one broad alarm override corroborated evidence |
| 0.10 NM in 6 minutes | Observed closing rate is 1.0 kn; verify the arithmetic independently |
| 0.35 NM at unchanged 1.0 kn | Nominal 21 minutes to the boundary—not safe waiting time |
| Wind, stream and neighbour geometry still changing | Expect the rate and route to change; act before the remaining options contract |
| Recovery may overload or foul | Protect crew and propulsion; use the planned release, assistance or abandonment boundary |
Turn evidence into the first command
One crew member wants to keep watching the GPS while another proposes using full windlass power to recover the chain quickly.
1. Declare the change
State that corroborated ground movement and the closing danger margin have crossed the release trigger; the operation is now a controlled escape, not routine watchkeeping.
2. Control the yacht
Muster crew, establish helm, propulsion, navigation and lookout roles, and keep the yacht clear of hazards and traffic through a vessel-specific plan.
3. Protect the foredeck
Keep people clear of the gypsy, chain and loaded cable, prevent cable or tripping lines reaching the propeller, and stop rather than overload abnormal or fouled gear.
4. Execute the fallback
Recover, re-anchor, leave, release marked gear or seek assistance according to the briefed plan and the margin that actually remains.
Sense check: The first command must control both the yacht and the people. 'Haul faster' does neither and may remove the remaining margin through injury, overload or loss of propulsion.
Common mistake or limitation
- Waiting for a broad anchor alarm even though independent visual, depth and ground observations agree that the relevant margin is closing.
- Treating 21 minutes as usable time instead of a nominal constant-rate warning that excludes manoeuvring and safety margins.
- Sending crew forward before helm, propulsion, lookout, communication, cable and propeller control have been assigned.
- Using full windlass power or vessel momentum as a universal breakout method when the cable or anchor is abnormally loaded or fouled.
- Focusing on gear recovery while losing navigation, traffic awareness, signals or the escape route.
Recap
- Corroborate ground movement; one alarm or one sensor must not overrule the wider evidence.
- 0.10 NM in 6 minutes is 1.0 kn, and 0.35 NM at that unchanged rate is a nominal 21 minutes.
- The calculation proves urgency, not safe waiting time.
- Muster crew, control the yacht, protect the cable and propeller, then execute the briefed recovery, departure or assistance plan.
Optional quick check
Section 7 of 7
The yacht closes 0.10 NM towards danger in 6 minutes and is 0.35 NM from the boundary. What does the calculation support?
Keep revising this topic
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
- RYA Yachtmaster Offshore examination scope
- RYA Coastal Skipper/Yachtmaster Offshore Theory course
- RYA Yachtmaster Handbook
- RYA Yacht Sailing Techniques
- RYA Anchoring with Care
- MCA MGN 592 Amendment 2 — anchoring, mooring, towing and hauling equipment
- MCA Code of Safe Working Practices for Merchant Seafarers 2026
- MAIB Safety Digest 2/2022 — anchor-windlass injury lesson
- Maritime New Zealand PS-04 — watchkeeping at anchor
Continue studying Anchorwork
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