Lesson previewBuild a Complete Night Character1 section shown
Preview lesson
Build a Complete Night Character
What you will learn
Report a light's colour, rate or character, group, period and charted position before naming an IALA mark or changing the route.
A night identification is a repeated pattern, not a flash count: observe the colour, character, complete group, eclipse and period, then compare the result with position and current information.
Read a notation such as VQ(3) W 5s in parts. VQ is the rate, three is the number of flashes in the group, W is white and five seconds is the period from the start of one complete character to the start of the next. 'Three flashes' omits most of the evidence.
Find a repeat before counting. A glimpse can start in the middle of a group or eclipse, so observe the group boundary, the following darkness and the same pattern beginning again. For a south cardinal, the long flash is part of the group rather than an optional seventh quick flash.
If colour, rate or period cannot be distinguished, retain that limit in the report. Do not turn an uncertain white-or-yellow glimpse or a few reflected flashes into a precise mark family. Another lookout, a steadier bearing and a longer observation may improve the evidence without closing the aid.
Treat the charted light as an expectation to test, not proof that the observed light is that aid. Position, bearing trend, neighbouring aids, depth and current chart or light information should agree before recognition becomes a route decision.
Read the complete character
Worked example: VQ(3) W 5s
East-cardinal candidate
- Colour
- White
- Rate
- Very quick
- Group
- 3 flashes
- Period
- 5 seconds
1. Observe
Find the group boundary, eclipse and repeat; three flashes seen mid-cycle are not enough.
2. Corroborate
Compare colour, rate, group, period, charted position and neighbouring aids.
3. Decide
East is the candidate safer-water relationship; chart, depth and vessel margin still define the route.
| Element | Question to answer | Worked observation |
|---|---|---|
| Colour | What colour is shown? | White |
| Rate / character | Quick, very quick, flashing, occulting or another form? | Very quick |
| Group | How many flashes belong together? | Three |
| Period | When does the same complete pattern restart? | Every 5 seconds |
| Position | Which current charted aid should be here? | East-cardinal candidate |
Turn three flashes into a defensible report
On an unfamiliar approach, three rapid white flashes appear near the expected position of an east cardinal. The first sighting began after the light was already flashing.
1. Keep the first report provisional
Say 'three rapid white flashes seen; group boundary not yet established' rather than naming the mark immediately.
2. Find the complete repeat
Observe the eclipse and the next group, distinguishing Q from VQ and checking whether the period is 10 or 5 seconds.
3. Corroborate the candidate
Compare bearing, charted east-cardinal position, neighbouring aids, depth and current light information.
4. Make the route decision separately
Use the charted point of interest, traffic, depth and vessel margin to decide the track; the flash count alone is not a helm order.
Sense check: The final report should contain colour, rate, group, period, position and any observation limitation—not just the number three.
Common mistake or limitation
- Counting flashes before finding the start and end of the repeating group.
- Omitting colour, period or uncertainty from the report.
- Treating a charted expectation as proof when the observed character does not yet agree.
Recap
- Read colour + rate or character + group + period + position.
- A partial glimpse is not a complete light character.
- Recognition proposes a family; current charted context and vessel constraints decide the route.
Optional quick check
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