Rule 30 · USCG Navigation Rules

Vessel aground

Anchor lights plus two all-round red lights in a vertical line — and three balls by day.

Viewpoint

Display

Drag to orbit freely, scroll or pinch to zoom — or use the viewpoint buttons above (keyboard friendly).

From the port bow you see:

All-round red (upper)
All-round red (lower)
white — Anchor light (forward)

→ Vessel aground — Aground, seen from the port bow.

Memory aid

“Anchor light PLUS red over red = she is on the bottom, not just stopped. Three balls by day.”

What it means

Aground

The anchor light(s) for her length PLUS red-over-red where best seen (a ship of 50 m or more also shows the lower aft anchor light). A vessel under 12 m aground need not show the reds or the three balls.

Day shapes

Three balls
Three balls in a vertical line where they can best be seen.

Light details

Light	Colour	Arc	Position
All-round red (upper)	red	360° all-round	Mast, vertical line (top)
All-round red (lower)	red	360° all-round	Mast, vertical line (2nd from top)
Anchor light (forward)	white	360° all-round	Forward, centreline

2D profile

Labelled side view — works without WebGL and in print. Variant shown: Aground.

Side view, seen from starboard — only the lights visible from that side are shown.

From dead ahead (her green appears on your left).

From astern.

In fog, she sounds

Vessel aground (fog)Bell ×3 + Bell 5 s + Bell ×3

Three distinct bell strokes, rapid ringing for 5 seconds, then three more strokes, every minute — “stuck – stuck – stuck” around the anchor signal.

Don’t confuse with…

Vessel not under command (NUC)

Rule 27

Vessel at anchor (under 50 m)

Rule 30

Vessel constrained by her draught (CBD)

Rule 28

Official source

Rule 30, reproduced from the public-domain COLREGs Rule 30(d) — USCG Navigation Rules. Diagrams and 3D scenes are original to boatrules.com.

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