Rule 34 - Maneuvering & Warning Signals

International

"I AM"
Signals my be supplemented by light signals, white light visible at 5 miles

Meeting or crossing and action is required (No answer is required)

Inland

"I INTEND"

Meeting or crossing at a distance within 1/2 mile, each vessel when maneuvering shall indicate the maneuver as follows

Overtaking in a narrow channel or fairway and action is required
international - any vessel
inland - PDV

A vessel nearing a bend or an area of a channel where other vessels may be obscured shall sound one prolonged blast

Signal shall be answered with a prolonged blast by an approaching vessel within hearing around the bend
come to an agreement when in sight of one another

inland only

allow vessels to reach agreement with one another in a head on crossing, or overtaking situation using VHF
If agreement is not reached, whistle signals shall be exchanged