Module 17 - Marine Environment
Responsible Anchoring
MMO guidance explains that anchors and chain can uproot, expose, scar and fragment seagrass. It advises checking mapped sensitive habitat, using advanced mooring systems where provided and respecting voluntary no-anchor zones. The same reasoning applies to other protected seabed features identified by the site's current management information.
A charted seabed abbreviation, depth contour or apparently bare patch is only part of the decision. The skipper must also check current habitat information, local restrictions or requests, available swinging room, expected weather and tide, the yacht's anchoring system, the quality of holding and the escape plan. A visitor mooring is useful only when it is authorised, suitable for the yacht and conditions, and inspected or used within the operator's stated limits.
Lower the anchor under control at the chosen clear position, lay the cable without dragging it across habitat, verify holding using the vessel's normal checks and monitor the result. When leaving, recover vertically as conditions allow rather than motoring the chain across the seabed. Do not use propeller or water-jet wash as a way to clean gear over sensitive habitat.
- Treat safety, holding, habitat and permission as separate checks
- Prefer a suitable authorised mooring or an authorised clear substrate when available
- Control anchor and cable movement to avoid dragging through habitat
- Monitor the yacht and keep a habitat-safe alternative
| Decision | Evidence needed | A false shortcut |
|---|---|---|
| Navigation safety | Depth, swinging room, shelter, traffic, tide and escape route | The chart shows an anchor symbol, so every condition is safe |
| Holding | Current seabed information, actual set and monitored position | Sand or mud always guarantees good holding |
| Habitat | Mapped features, visual information where reliable and site guidance | A clear-looking patch proves no sensitive habitat exists |
| Permission | Current byelaw, harbour direction, zone or voluntary arrangement | A protected-area name alone proves either a ban or permission |
| Mooring suitability | Authorisation, yacht limits, condition and expected load | Any buoy is safer than anchoring |
Optional quick check
Section 6 of 8
A chart suggests sand, but current site guidance maps seagrass at the intended position. What is the sound response?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
Continue studying Marine Environment
This public lesson is part of Revision Module 17. Full revision access adds the guided Learn, Practise and Test flow, flashcards and revision progress.