6.1 General Rules, Look-out, Safe Speed & Risk of Collision (Rules 1-8)
Key Takeaways
Rule 1 establishes that the International Regulations for Preventing Collisions at Sea (IRPCS) apply to all vessels on the high seas and all connected navigable waters accessible to seagoing vessels.
Rule 2 codifies the ordinary practice of seamen and authorizes departures from the Rules only when strictly necessary to avoid immediate danger.
Rule 5 mandates maintaining a continuous, proper look-out by sight, hearing, and all available means appropriate to prevailing conditions (including radar, AIS, and depth sounders).
Rule 7 dictates that a risk of collision exists if the compass bearing of an approaching vessel does not appreciably change as range closes, requiring systematic hand-bearing compass readings.
Rule 8 requires collision-avoidance actions to be positive, made in ample time, and substantial enough to be readily apparent visually or on radar, avoiding a succession of small alterations and checking that the action achieves safe clearance.
6.1 General Rules, Look-out, Safe Speed & Risk of Collision (Rules 1-8)
Note
The International Regulations for Preventing Collisions at Sea 1972 (IRPCS / COLREGs) form the universal legal foundation of maritime safety. They establish duties for avoiding collisions and require the precautions of ordinary seamanship and the special circumstances of each case.
Part A: General Principles (Rules 1–3)
Rule 1: Application
Rule 1(a) establishes that the IRPCS apply to all vessels upon the high seas and connected navigable waters. Under Rule 1(b), local bylaws (such as harbour regulations) take precedence within their jurisdiction but must conform as closely as possible to the IRPCS. Where local rules are silent, the IRPCS govern.
Rule 2: Responsibility & Good Seamanship
Rule 2 codifies seamanship through two foundational principles:
- Rule 2(a) (Ordinary Practice of Seamen): Exonerates no vessel, master, or crew from the consequences of neglecting the Rules or ordinary seamanship precautions.
- Rule 2(b) (Departure to Avoid Immediate Danger): Due regard must be given to all dangers of navigation and special circumstances—including vessel limitations—that make departing from the Rules necessary to avoid immediate danger.
Important
Rule 2(b) is not a general escape clause. A departure must be necessary to avoid immediate danger, taking account of navigation and collision hazards, special circumstances and vessel limitations. This is not confined to an inevitable collision and does not excuse ignoring ordinary seamanship.
Rule 3: General Definitions
- Vessel: Any watercraft (including non-displacement craft, WIG craft, and seaplanes) used for water transportation.
- Power-Driven Vessel: Any vessel propelled by machinery. A sailing yacht motoring with sails hoisted is legally a power-driven vessel.
- Sailing Vessel: Any vessel under sail provided propelling machinery, if fitted, is not being used.
- Vessel Engaged in Fishing: Any vessel fishing with nets, lines, or trawls that restrict manoeuvrability. Excludes trolling lines or other fishing gear that does not restrict manoeuvrability.
- Vessel Not Under Command (NUC): A vessel unable to manoeuvre as required by these Rules due to an exceptional circumstance (e.g., steering failure, engine breakdown) and unable to keep clear.
- Vessel Restricted in Her Ability to Manoeuvre (RAM): A vessel restricted in manoeuvrability by the nature of her work (e.g., cable laying, dredging, surveying, or difficult towing operations).
- Vessel Constrained by Her Draught (CBD): A power-driven vessel whose draught in relation to the available depth and width of navigable water severely restricts her ability to deviate from course.
- Underway vs. Making Way: Underway means not at anchor, made fast to shore, or aground. An underway vessel is making way when moving through the water. She is making no way when stopped relative to the water; stopping the engine alone does not establish this.
Part B Section I: Conduct in Any Condition of Visibility (Rules 4–8)
Rules in Section I apply in all conditions of visibility, from clear daylight to dense fog.
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 and conditions so as to make a full appraisal of the situation and of the risk of collision."
Small craft skippers must maintain:
- 360° Visual Vigilance: Scanning all sectors; checking behind sails and cockpit enclosures.
- Aural Monitoring: Listening for fog signals, engine noise, and surf.
- All Available Means: Systematic use of radar, AIS, echo sounders, and VHF Channel 16.
- Unattended Helm Trap: Leaving the helm unattended while looking at chartplotters below violates Rule 5. Continuous human look-out is mandatory even under autopilot.
Rule 6: Safe Speed
Every vessel must proceed at a safe speed so she can take proper avoiding action and be stopped within an appropriate distance:
| General Factors (All Vessels) | Radar Factors (Radar-Equipped Vessels) |
|---|---|
| Visibility: Mist, rain, darkness, glare. | Radar Limitations: Antenna height, beam width. |
| Traffic Density: Concentrations of shipping. | Range Constraints: Monitoring multiple ranges. |
| Manoeuvrability: Stopping distance and turning. | Clutter: Sea and rain clutter masking targets. |
| Background Lighting: Backscatter from shore. | Undetected Targets: Small boats, ice missed. |
| Wind, Sea & Current: Heavy swell and tide. | Target Tracking: Number and vectors of targets. |
| Draught vs. Depth: Under-keel clearance. | Visibility Assessment: Radar range measurements. |
Rule 7: Risk of Collision
Every vessel must determine if risk of collision exists; if there is any doubt, risk shall be deemed to exist. Never make assumptions on scanty information, especially scanty radar data.
The Compass Bearing Method
Systematic observation of an approaching vessel using a hand-bearing compass:
- If the compass bearing does not appreciably change as range closes, a risk of collision exists.
- A changing bearing does not by itself establish safe clearance. Use systematic bearings, range and relative motion to assess the passing distance, and continue checking until the vessel is past and clear.
Warning
Under Rule 7(d)(ii), risk can exist even with appreciable bearing change when approaching a very large vessel, a long tow, or any vessel at very close range.
Rule 8: Action to Avoid Collision
- Positive & In Ample Time: Take effective action early, with due regard to good seamanship and the circumstances.
- Large & Readily Apparent: If circumstances admit, course or speed changes must be large enough to be readily apparent visually or by radar. Avoid a succession of small alterations; the Rule prescribes no fixed turn angle.
- Course Alteration Alone: If sufficient sea room exists, a bold alteration of course alone is often the most effective action.
- Safe Passing Distance: Action must ensure safe passing, monitored until the target is finally past and clear.
- Slackening Speed: If necessary to avoid collision or assess the situation, a vessel must slacken speed or stop all way.
Summary of Rules 1–8 Key Terms & Exam Pitfalls
| Rule | Legal Mandate | Common Examination Trap |
|---|---|---|
| Rule 2 | Seamanship & emergency departure. | Believing Rule 2 allows ignoring rules for convenience. |
| Rule 3 | Statutory vessel definitions. | Assuming a motor-sailing yacht has sailing privileges. |
| Rule 5 | Continuous look-out by all means. | Relying solely on AIS while staying below. |
| Rule 6 | Safe speed adapted to conditions. | Assuming safe speed means a fixed speed limit. |
| Rule 7 | Steady compass bearing indicates risk. | Assuming a slight bearing shift guarantees clearing a large ship. |
| Rule 8 | Bold, early action; safe clearance. | Making three 3-degree course adjustments instead of one bold turn. |
A sailing yacht is navigating across open water at night. The skipper sights a white masthead light and a green sidelight on the port bow. Over an 8-minute period, the hand-bearing compass bearing to the lights remains constant at 040° while the radar range decreases from 5 nautical miles to 2.5 nautical miles. What does Rule 7 dictate, and what action should be taken under Rule 8?
A risk of collision exists; the skipper must assess responsibilities and take early, positive action large enough to be readily apparent to the approaching vessel.
Because the approaching vessel shows a green sidelight, she is the give-way vessel; the yacht must maintain course and speed without exception.
A constant compass bearing indicates both vessels are travelling on parallel tracks, meaning they will pass clear at close quarters.
The yacht should make a succession of small 2-degree alterations to starboard to gently open the passing distance without disturbing off-watch crew.
A 12-metre yacht is sailing with mainsail hoisted and drawing, but the skipper has engaged the diesel engine at 1,800 RPM to maintain speed against a foul tide. Under Rule 3 of the IRPCS, what is the legal status of this vessel?
A sailing vessel, because her sails are hoisted and actively generating aerodynamic drive.
A power-driven vessel, because propelling machinery is being used regardless of whether sails are set.
A vessel restricted in her ability to manoeuvre, because the combination of wind and engine creates conflicting propulsion dynamics.
A hybrid craft entitled to sailing vessel privileges provided she exhibits a motoring cone pointing apex upwards.
Under Rule 6 of the IRPCS, which set of factors must be evaluated specifically by a vessel utilizing operational marine radar when determining safe speed?
The fuel consumption rate per nautical mile and the battery charging capacity of the alternators.
The height of the tide relative to Mean Low Water Springs and the maximum draft of the local pilot boat.
Radar limitations, operational range scales, sea and rain clutter attenuation, and the possibility of missing small fibreglass craft or ice.
The geographic distance to the nearest VHF coastal radio station and the barometric pressure gradient.
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