Sound signals, lights and day shapes.

The signals of the COLREGs, the rules at sea, in short. Not the official text.

Inland waters have their own rules: CEVNI on most European waterways, the BPR in the Netherlands, the RPR on the Rhine. Their lights and signals differ in places.

Sound signals

A short blast lasts about one second, a prolonged blast four to six.

Maneuvering, in sight of each other

I am altering my course to starboard.

I am altering my course to port.

I am operating astern propulsion.

I don't understand your intentions, or doubt you are doing enough to avoid a collision.

Coming up to a bend or a spot where boats may be hidden. A boat behind it answers the same.

Overtaking in a narrow channel

I intend to overtake you on your starboard side.

I intend to overtake you on your port side.

Agreed: the boat ahead lets the other pass.

In restricted visibility, at least every two minutes

Power-driven, making way through the water.

Power-driven, under way but stopped.

Sailing, fishing, towing, not under command or restricted in maneuvering.

Being towed, sounded right after the tow's signal.

At anchor, to warn a boat coming close. Besides the bell.

At anchor: the bell rung rapidly for 5 seconds every minute.
Aground: three strokes of the bell, the rapid ringing, three strokes again.
Under 12 m a boat may give any other clear sound signal instead, at least every two minutes.

Lights by night

Seen from dead ahead: her starboard green on your left, her port red on your right.

Day shapes

Black shapes, hoisted where they can best be seen. Top to bottom.

Sound signals, lights and day shapes.

Sound signals

Maneuvering, in sight of each other

Overtaking in a narrow channel

In restricted visibility, at least every two minutes

Lights by night

Day shapes

Signal flags

Morse and the phonetic alphabet

Buoyage

Beaufort scale

VHF channels

Local rules

The instrument beside the helm.