Module 3 - Anchorwork
Anchoring Technique
What you will learn
Brief, lower, lay and set an anchor under control, calculate a starting cable length from maximum bow-to-seabed depth, and verify the result with more than one position cue.
A sound anchoring sequence controls the vessel while the anchor and cable are lowered, develops load gradually to test the set, and keeps monitoring after the engine is neutral. The familiar 4:1 and 6:1 ratios are starting guides, not guarantees.
Brief the drop point, intended depth and cable, roles, signals, hazards, abort and recovery plan before entering the final approach. Approach slowly against the dominant wind or stream when the surrounding hazards permit, stop over the chosen position, then lower the anchor under control. Let the yacht move astern while veering cable so it lays out rather than piling on the anchor or running across crew.
For the RYA starting guide, scope uses the greatest expected vertical distance from the bow roller to the seabed: maximum water depth during the stay plus bow height. About 4:1 for all chain and 6:1 for warp with a short length of chain are useful moderate-condition starting points. Wind, sea, stream, bottom, vessel, maker guidance and available room may require more cable or a different anchorage; a snubber can transfer load away from the windlass and add elasticity where appropriate.
Set the anchor by bringing the cable under increasing astern load in a controlled manner while observing the cable and the vessel's movement. Use a well-oriented shore transit where available, but remember that one transit may not reveal motion along its line. Corroborate with another bearing or transit, GNSS position or alarm, depth trend, cable behaviour and continued weather and traffic checks. A steady electronic display or one aligned pair is not a guarantee.
Worked example
Current depth is 3 m, the tide will rise another 2 m before high water, the bow roller is 1 m above the surface, and an initial 4:1 all-chain guide is being used.
- 1Maximum water depth during the stay: 3 m + 2 m tidal rise = 5 m.
- 2Maximum bow-roller-to-seabed distance: 5 m + 1 m bow height = 6 m.
- 3Starting cable length: 6 m × 4 = 24 m of chain.
- 4Check that the resulting swing clears every hazard and increase cable or change anchorage if conditions, bottom or guidance require it.
Sense check: Using only the present 3 m sounding would give 12 m and ignore both the tidal rise and bow height; that is not the stated scope geometry.
| Evidence | What it can show | Important limitation |
|---|---|---|
| Shore transit | Movement across a chosen line of sight | May miss movement along the transit; objects must be fixed and well separated |
| GNSS position or anchor alarm | Movement beyond a configured radius | Reference point, normal swing, position error, power and alarm audibility matter |
| Depth trend | Unexpected movement across a sloping bottom | A flat bottom can hide movement and transducer offset must be understood |
| Cable and vessel behaviour | Load, vibration, yaw and continuing astern movement | No single feel or angle proves secure holding in changing conditions |
Lay and verify the fictional cove anchor
The yacht will remain through high water on a sand shelf. Maximum water depth is 4 m, the bow roller is 2 m above the water, and the planned starting guide is 4:1 all chain.
1. Brief and approach
Agree the 24 m starting cable, crew signals, drop point and abort, then approach slowly against the dominant force with an escape route clear.
2. Lower and veer
Stop over the drop, lower rather than throw, and let the yacht fall astern while the cable is paid without piling or running uncontrolled.
3. Set progressively
Snub or make fast as planned, apply increasing astern load and stop if the lead, equipment or crew position becomes unsafe.
4. Corroborate holding
Check a useful shore transit plus an independent cue, set an appropriate alarm and keep monitoring the forecast, swing and neighbouring craft.
Sense check: The 24 m result is a checked starting length for this fictional moderate-condition arrangement, not a universal prescription for every yacht or anchorage.
Common mistake or limitation
- Calling 4:1 chain or 6:1 mixed rode a universal minimum without checking conditions, maker guidance, maximum depth and available swing.
- Throwing the anchor or dumping cable in a heap, which can foul the anchor and removes control from the crew.
- Assuming one steady transit proves the yacht is stationary even when movement could occur along that line of sight.
- Treating a chartplotter anchor alarm as an automatic watch instead of one correctly configured aid within continued monitoring.
Recap
- Brief and control the approach, lowering, cable run and progressive setting load.
- Calculate the starting cable from maximum bow-to-seabed depth, then test it against conditions and swinging room.
- Verify holding with corroborating evidence and continue an appropriate anchor watch.
Optional quick check
Section 3 of 7
Current depth is 3 m, a 2 m tidal rise is expected and the bow roller is 1 m above the water. What is the 4:1 all-chain starting length?
Common questions
How much anchor chain should I put out?
About four times maximum bow-to-seabed depth is a common all-chain starting guide in moderate conditions. The actual plan must account for bottom, wind, sea, stream, vessel, equipment guidance and safe swinging room.
How do I know whether the anchor is holding?
Apply a controlled setting load, then corroborate a well-oriented transit with another position cue such as a second bearing, GNSS alarm, depth trend or cable behaviour. Continue monitoring as conditions change.
Should an anchor be thrown?
No. Stop over the intended drop and lower it under control, then veer cable as the yacht moves astern so the rode lays out cleanly.
Keep revising this topic
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
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