Lesson previewRead a Visual Signal as a Complete Report1 section shown
Preview lesson
Read a Visual Signal as a Complete Report
What you will learn
Build a complete CEVNI visual-signal report from position, colour, number, geometry, rhythm, vessel context and day-or-night form before deciding what the boat should do.
A light or shape is not a vocabulary card floating on its own. Its position and pattern identify a vessel, formation, operation or status; that meaning then changes the skipper's room, speed or route.
Start with raw observations. Record whether a light is white, red, green, yellow or blue; fixed, scintillating or swinging; single or grouped; all-round or directional; high, low, forward, aft or on one side. By day, record the exact ball, cone, bicone, cylinder, flag or board and how it is arranged.
Next identify the carrier. The same colour can mean different things when it is steady rather than scintillating, placed on a vessel rather than a shore signal, or carried by one vessel rather than the head or pusher of a formation. Count and geometry matter: three white lights in a triangle at a pushed convoy's head are not three white lights in a horizontal row on its pusher.
Only then state the operational consequence. Decide whether the object is a single vessel, tow, pushed convoy, ferry, dangerous-goods carrier, working obstruction or vessel unable to manoeuvre; identify the clear or blocked side where applicable; and control speed and position before a bend, bridge or narrow reach removes options.
| Observation field | What to record | Why it matters |
|---|---|---|
| Colour and rhythm | Steady, scintillating, quick or swinging | Separates status signals that share a colour |
| Number and geometry | Vertical, horizontal or triangular arrangement | Identifies formations and clear or blocked sides |
| Position | Forward, aft, outside edge, fairway side or shore | Shows which vessel or part of a formation carries it |
| Context | Underway, stationary, working, meeting or controlled passage | Limits which interpretation is defensible |
| Action | Keep clear, use the clear side, hold or verify | Turns recognition into a safe decision |
Report before naming
At night you see three white lights near the bow of a large inland formation and three white lights spread horizontally at the after end.
1. Observe
State the forward triangular group and the after horizontal group rather than reporting only six white lights.
2. Interpret
Use their geometry and positions to identify the head and pusher markings of a pushed convoy.
3. Act
Treat the whole formation as connected traffic, keep clear early and never aim through an apparent internal gap.
Sense check: If the report loses the triangle, horizontal row or vessel position, it loses the evidence that supports the identification.
Common mistake or limitation
- Naming a vessel from colour alone while ignoring rhythm, count, geometry and position.
- Learning a night light and assuming every status has an identical daytime equivalent.
- Giving a correct label without the room, route or control decision that follows from it.
Recap
- Report raw cues, then identify the vessel or status, then state the action.
- Distinguish steady, scintillating and swinging lights explicitly.
- Treat every formation as a whole until its limits and safe passing side are resolved.
Optional quick check
Section 1 of 1