At anchor, aground, and the small-boat exemptions
1The lesson in plain words
At anchor, show the required anchor light instead of your underway lights. Small-boat exemptions have specific conditions.
At anchor
A vessel at anchor shows an all-round white light forward and a second, lower one at or near the stern (Rule 30(a)). Under 50 m, one all-round white light where it can best be seen is enough. By day, hoist one black ball forward. Switch off your masthead light, sidelights and sternlight: they indicate underway. Show the required anchor light instead.
Where to put it
Under 50 m, show one all-round white light where it can best be seen. Keep its view clear of sails and fittings. You may also illuminate your decks; at 100 m or more this is required. Extra lights must not mask your navigation lights or be mistaken for them.
The under-7 m exemption
A boat under 7 m at anchor need not show the anchor light or ball, but only when she is not in or near a narrow channel, fairway or anchorage, or where other vessels normally navigate (Rule 30(e)). Anchorages are excluded, so at a normal anchorage you still show the light.
Aground
A vessel aground shows her anchor lights and adds two all-round red lights in a vertical line; by day, three balls in a vertical line (Rule 30(d)). Under 12 m you need not show these aground signals (Rule 30(f)), but you still show the anchor light. Then call for help if you need it.
Fog and other lights
In or near restricted visibility, the standard anchor signal is rapid bell ringing for about 5 seconds at intervals of not more than 1 minute. Under 12 m, you may instead make another efficient sound signal at intervals of not more than 2 minutes (Rule 35(j)); this alternative also applies from 12 m to under 20 m (Rule 35(i)). Extra lights must not hide or imitate navigation lights. Full text: /colreg/rule-30 and /colreg/rule-35.
2Key data
- At anchor, 50 m or more
- All-round white forward, a lower one aft
- At anchor, under 50 m
- One all-round white where best seen
- Anchor day shape
- One black ball forward
- Aground
- Anchor lights + two red all-round; by day three balls
- Under 7 m at anchor
- Exempt only away from narrow channels, fairways, anchorages, traffic
- Under 12 m aground
- Aground signals not required; anchor light still is
3Key points
- 1
At anchor under 50 m: one all-round white light; by day, one black ball.
- 2
Switch off the masthead light, sidelights and sternlight at anchor; show the required anchor light instead.
- 3
The under-7 m exemption never applies in or near an anchorage, a narrow channel or fairway.
- 4
Aground: anchor lights plus two all-round reds; by day three balls. Under 12 m, omit only the reds and balls.
4Frequent mistakes
Wrong: Small boats never need an anchor light.
Right: Only boats under 7 m are exempt, and only away from narrow channels, fairways, anchorages and normal traffic.
Wrong: Leave the underway lights on at anchor so others see you better.
Right: The masthead light, sidelights and sternlight indicate underway. Switch them off and show the required anchor light instead.
Wrong: A small boat aground needs no lights at all.
Right: Under 12 m you may omit the two red lights and three balls, but the anchor light still applies.
5Practice case & exam keys
You anchor your 6.5 m motorboat for the night in a marked anchorage where other yachts are coming and going. A friend says boats under 7 m need no anchor light.
Show the answer
The under-7 m exemption applies only away from narrow channels, fairways, anchorages and places where vessels normally navigate. You are in an anchorage, so show an all-round white light where it can best be seen, and switch off your masthead light, sidelights and sternlight. In fog, make an efficient sound signal at intervals of not more than 2 minutes.
Exam keys
- At anchor: white forward and a lower white aft; under 50 m one all-round white; ball by day.
- Under 7 m at anchor: exempt only away from narrow channels, fairways, anchorages and normal traffic.
- Aground: anchor lights plus two all-round reds; by day three balls. Under 12 m, omit only the reds and balls.
- At anchor: masthead light, sidelights and sternlight off; anchor light on. Deck lighting required at 100 m or more.
Finish this unit
When you've read it, match the terms, then answer three questions. Get them all right to finish the unit; opening the page alone doesn't count.
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