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Vessel constrained by her draught

Power-driven lights plus three red all-round lights in a vertical line. Normal power-driven lights plus three reds in a vertical line: she cannot leave the deep channel.

fog
60°

Drag across the scene to walk around the ship. Tap a light to see its name.

arcs = Rule 21 sectors

One prolonged and two short blasts at intervals of not more than 2 minutes (Rule 35c).

Lights (Rule 28)

LightColourSectorHeight above water
white forward masthead light white masthead, 225° (from right ahead to 22.5° abaft the beam on each side) 16 m
white after masthead light (50 m and over) white masthead, 225° (from right ahead to 22.5° abaft the beam on each side) 20.5 m
red all-round light (upper) red all-round, 360° 19.4 m
red all-round light (middle) red all-round, 360° 17.4 m
red all-round light (lower) red all-round, 360° 15.4 m
green sidelight (starboard) green sidelight, starboard, 112.5° 13 m
red sidelight (port) red sidelight, port, 112.5° 13 m
white sternlight white stern, 135° (around the stern) 6 m

Model: a 90 m ship with the superstructure aft. Heights and positions follow COLREG Annex I (positioning of lights).

Day shapes

Shapes are black and hoisted where they can best be seen: a ball at least 0.6 m in diameter, vertical spacing at least 1.5 m (Annex I, section 6). Set the trainer above to day to see them.

Fog signal

One prolonged and two short blasts at intervals of not more than 2 minutes (Rule 35c).

A short blast lasts about 1 second, a prolonged blast 4 to 6 seconds (Rule 32). The play button is in the trainer above.

What to watch for

Three reds in a vertical line = constrained by draught. RAM is red-white-red.

By day: a cylinder.

Quick answers

What lights does a vessel constrained by her draught show at night?

Power-driven lights plus three red all-round lights in a vertical line. In full: white forward masthead light; white after masthead light (50 m and over); red all-round light (upper); red all-round light (middle); red all-round light (lower); green sidelight (starboard); red sidelight (port); white sternlight.

What day shapes does a vessel constrained by her draught show?

By day she shows: cylinder.

What is the fog signal of a vessel constrained by her draught?

One prolonged and two short blasts at intervals of not more than 2 minutes (Rule 35c).

Test yourself: lights quiz All 13 vessel types Open in the trainer