Rule 30 · USCG Navigation Rules
Vessel at anchor (50 m or more)
Two all-round white anchor lights — forward one higher, after one lower — and deck illumination is mandatory from 100 m.
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:
- white — Anchor light forward (higher)
- white — Anchor light aft (lower)
→ Vessel at anchor (50 m or more) — At anchor, seen from the port bow.
Memory aid
“Big ship asleep: white forward HIGH, white aft LOW — underway steaming lights slope the other way.”
What it means
At anchor
Forward light HIGHER, after light lower — the reverse of underway masthead lights. Any anchored vessel MAY light her decks; a vessel of 100 m or more MUST.
Day shapes
Anchor ball
One ball in the fore part where it can best be seen.
Light details
| Light | Colour | Arc | Position |
|---|---|---|---|
| Anchor light forward (higher) | white | 360° all-round | Forward, centreline |
| Anchor light aft (lower) | white | 360° all-round | Aft, raised above the stern |
2D profile
Labelled side view — works without WebGL and in print. Variant shown: At anchor.
In fog, she sounds
Don’t confuse with…
Official source
Rule 30, reproduced from the public-domain COLREGs Rule 30 — USCG Navigation Rules. Diagrams and 3D scenes are original to boatrules.com.