Convention on the International Regulations for Preventing Collisions at Sea (COLREGs)

COLREGs establishes a set of navigation rules designed to prevent collisions between vessels at sea. Adopted by the International Maritime Organization (IMO), COLREGs are recognized and must be adhered to by all vessels operating in international waters. The regulations are structured into 41 rules and organised into five parts: Part A (General), Part B (Steering and Sailing), Part C (Lights and Shapes), Part D (Sound and Light Signals), and Part E (Exemptions). Below are some of the key rules that every seafarer must understand and apply.

Rule 5: Lookout

Always maintain a proper look-out by sight and hearing as well as by all available means, such as radar, to make a full appraisal of the situation and the risk of collision.

• Seafarers must constantly observe their surroundings to detect other vessels, navigation hazards, or potential dangers. The look-out must be vigilant at all times, particularly in conditions of restricted visibility.

Rule 6: Safe speed

Proceed at a safe speed so that proper and effective action can be taken to avoid collision and stop within a distance appropriate to the prevailing circumstances and conditions.

• The concept of safe speed is critical. Seafarers must adjust the ship’s speed based on visibility, traffic density, manoeuvrability, and proximity to navigational hazards. Slower speeds may be necessary in fog, at night, or in busy shipping lanes.

Rule 7: Risk of collision

Every vessel must use all available means to determine if a risk of collision exists. If there is any doubt, such risk shall be deemed to exist.

• Seafarers must use radar, visual bearings, and other tools to assess whether a risk of collision is developing. A change in the compass bearing of an approaching vessel is a key indicator.

Rule 8: Action to avoid collision

Any action taken to avoid a collision shall be positive, made in ample time, and with due regard to the observance of good seamanship.

• If a collision risk is identified, seafarers must take decisive action—altering course or speed—to avoid the collision. Such actions should be clear and noticeable to other vessels.

Rule 9: Narrow channels

In narrow channels, keep as close to the outer limit of the channel on your starboard side as is safe and practical.

• Vessels navigating narrow channels must stay on the right side (starboard) and be prepared to give way to vessels restricted in their ability to maneuver, such as those constrained by their draft.

Rule 10: Traffic separation schemes

Vessels must navigate with particular caution within traffic separation schemes, keeping to the lanes assigned for their direction of travel.

• Seafarers must adhere to designated traffic lanes, avoid crossing traffic lanes, and enter or leave the scheme at designated locations.

Rule 13: Overtaking

An overtaking vessel must keep out of the way of the vessel being overtaken.

• If one vessel is overtaking another, it is the responsibility of the overtaking vessel to avoid the vessel being overtaken by a safe distance.

Rule 15: Crossing situation

When two power-driven vessels are crossing so as to involve risk of collision, the vessel which has the other on her starboard side shall keep out of the way.

• In crossing situations, the vessel that sees another vessel on its starboard (right) side must take action to avoid crossing in front of that vessel.

Rule 18: Responsibilities between vessels

Underway vessels have varying responsibilities to avoid collisions depending on their type and situation. Power-driven vessels must give way to vessels restricted in their ability to maneuver, vessels engaged in fishing, and sailing vessels.

• The hierarchy of responsibilities is crucial for seafarers to understand. Generally, vessels that are less maneuverable (e.g., those restricted by their draft or engaged in fishing) have the right of way over more maneuverable vessels.

Rule 19: Conduct of vessels in restricted visibility

In conditions of restricted visibility, vessels must proceed at a safe speed and be prepared to maneuver.

• Seafarers must be particularly cautious in fog, heavy rain, or other conditions that limit visibility. The use of radar, sound signals, and reduced speed is essential to avoid collisions.