Lesson previewChoosing Shelter1 section shown
Preview lesson
Choosing Shelter
What you will learn
Choose an anchoring position that remains suitable through the planned stay by checking shelter, depth, bottom, swing, restrictions, traffic and a usable exit together.
A calm-looking patch of water is only the starting point. A usable anchorage must remain sheltered, deep enough, clear and permitted as wind, stream and water level change.
Plan for the whole stay rather than the arrival snapshot. Compare the forecast wind and sea with the land that provides shelter, then consider how a wind shift or tidal-stream reversal changes exposure and the direction in which the boat will lie. A place sheltered now can become a lee shore later.
Use a current chart and local information to check charted depth, obstructions, cables, pipelines, narrow channels or fairways, prohibited areas and environmental restrictions. COLREG Rule 9 requires a vessel, if circumstances admit, to avoid anchoring in a narrow channel; it is not an unconditional statement that every emergency use of an anchor in every channel is forbidden.
Check the lowest expected water level for under-keel clearance and the greatest expected depth for cable. Then allow a swept area around the drop point for paid cable, the boat's length, neighbouring craft and changes in wind or stream. Seabed descriptions indicate likely conditions, not guaranteed holding, so the set must still be tested and monitored.
| Decision | Evidence to use | Reason to reject or move |
|---|---|---|
| Shelter | Forecast wind, sea and local topography through the stay | A later direction exposes the boat or creates a lee shore |
| Depth | Charted depth, tide, draught, sounder reference and margin | Low-water clearance or maximum-depth cable is inadequate |
| Swing | Cable, boat length, neighbours, shore, shoals and traffic | The swept area crosses a hazard or obstructs navigation |
| Bottom and permission | Chart, local directions, habitat guidance and actual set | A cable, restriction, sensitive habitat or uncertain holding conflicts with the plan |
Reject a sheltered arrival that will not remain safe
A bay is calm in the present westerly wind. The forecast backs south overnight, low water removes 1.2 m of depth and the planned cable would let the boat sweep across the entrance.
1. Project conditions
Reassess shelter and wave exposure for the forecast southerly wind, not only the present westerly.
2. Check both depth limits
Use low water for clearance and the greatest expected bow-to-seabed distance for the cable plan.
3. Draw the swept area
Include the cable, boat, neighbours and entrance traffic through the expected wind and stream changes.
4. Keep the exit usable
Choose another position before dark if the later shelter, depth or escape route does not retain a clear margin.
Sense check: The fact that another yacht is anchored nearby does not prove its draught, cable, permission, watch or forecast assumptions match yours.
Common mistake or limitation
- Treating an anchorage symbol or a cluster of boats as a guarantee of permission, depth, shelter or holding.
- Checking only the current wind and forgetting the later lee shore, stream reversal or different swing of nearby craft.
- Using the present sounder value without relating it to charted depth, tide, draught and the instrument's reference.
Recap
- A good anchorage keeps shelter, depth, swing, holding potential, permission and escape acceptable together.
- Seabed labels and other anchored boats are evidence to investigate, not guarantees.
- Move or change the plan while the alternative remains easy to use.
Optional quick check
Section 1 of 1