The rules in this part apply in any condition of visibility, whether or not vessels can see each other.
Rule 5 - Look-out
Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances, so as to make a full appraisal of the situation and of the risk of collision.
Rule 6 - Safe speed
Every vessel shall proceed at a safe speed so that she can take proper and effective action to avoid collision and be stopped within a distance appropriate to the prevailing circumstances. Factors include visibility, traffic density, manoeuvrability, background light at night, state of wind, sea and current, draught in relation to depth, and the limitations of radar equipment.
Rule 7 - Risk of collision
Use all available means, including radar, to determine whether risk of collision exists. If there is any doubt, such risk shall be deemed to exist. If the compass bearing of an approaching vessel does not appreciably change, such risk shall be deemed to exist. Risk may sometimes exist even with an appreciable bearing change, particularly when approaching a very large vessel or a tow. Do not make assumptions on the basis of scanty information, especially scanty radar information.
Rule 8 - Action to avoid collision
- Action shall be positive, made in ample time and with due regard to good seamanship.
- Alterations of course and/or speed shall be large enough to be readily apparent to another vessel; avoid a succession of small alterations.
- If there is sufficient sea room, an alteration of course alone may be the most effective action, provided it does not result in another close-quarters situation.
- If necessary, slacken speed or take all way off.
Rule 9 - Narrow channels
A vessel proceeding along a narrow channel shall keep as near to the outer limit of the channel on her starboard side as is safe and practicable. Vessels of less than 20 m and sailing vessels shall not impede the passage of a vessel which can safely navigate only within the channel. A vessel nearing a bend sounds one prolonged blast. Avoid anchoring in narrow channels.
Rule 10 - Traffic separation schemes
Proceed in the appropriate traffic lane in the general direction of traffic flow, keep clear of a separation line or zone, and normally join or leave at the termination of the lane. Cross the lane as nearly as practicable at right angles to the general direction of traffic flow.
The next part covers the rules for vessels in sight of one another (Rules 11-18).