Module 18 - Signals & Communications
Harbour and Traffic Signals
What you will learn
Use current local traffic signals and VHF reporting instructions as one input to a safe harbour approach, without treating permission as proof of navigational safety.
Harbour lights, boards, flags and channels are local systems. Appraise them before arrival, monitor the published channel and preserve a safe holding option when a signal or instruction is unclear.
Harbour entrances, locks, bridges, and traffic-controlled channels may display lights, boards, flags, or VHF instructions. The exact system is local, so the skipper must check the almanac, sailing directions, harbour website, local notices, and VHF working channel before arrival.
Never assume that a green light alone makes an entrance safe. It may only mean permission to proceed subject to depth, traffic, weather, and local instructions. If a signal is unclear, hold clear in safe water and call harbour control.
Resolve an unclear entrance light
The harbour website and an older almanac appear to show different reporting points. A green entrance light is visible, but the cross tide and depth margin are marginal.
1. Check currency
Use the current harbour authority source, local notices and published working channel to resolve the procedure.
2. Hold a safe option
Remain clear in navigable water while the signal or instruction is uncertain.
3. Reassess navigation
Treat traffic permission separately from depth, tide, weather, vessel handling and collision obligations.
Sense check: The skipper can explain both whether entry is authorised and whether entry is safe now; those answers may differ.
Common mistake or limitation
- A green traffic light does not guarantee sufficient depth, sea room, weather or freedom from collision risk.
- Do not choose between conflicting local sources by age or familiarity alone; identify the current authority and notice status.
- Calling harbour control does not transfer command responsibility to the controller.
- Do not enter a controlled area against a closed signal merely because another small vessel has done so.
Recap
- Obtain local signals, reporting points and working channels before arrival.
- Monitor early enough to understand traffic before the decision point.
- Hold clear when a signal or instruction is uncertain.
- Traffic permission and safe navigation remain separate tests.
Optional quick check
Section 9 of 18
Harbour control clears a yacht to enter, but the skipper cannot confirm sufficient depth. What is the best response?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
Continue studying Signals & Communications
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