Rule 7 - Risk of collision

ROR - Rule 7 Risk of collision
Section I – Conduct of vessels in any condition of visibility

Rule 7 - Risk of collision

(a) Every vessel shall use all available means appropriate to the prevailing circumstances and conditions to determine if risk of collision exits. If there is any doubt such risk shall be deemed to exist.

(b) Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk collision exists. If there is any doubt such risk shall be deemed to exist.

(c) Assumptions shall not be made on the bases of scanty information, especially scanty radar information.

(d) In determining if risk collision exists the following considerations shall be among those taken into account:

(i) such risk shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change;

(ii) such risk may sometimes exist even when an appreciable bearing change is evident, particularly when approaching a very large or a tow or when approaching a vessel at close range.

Questions & Answers

Q1. What would you use to determine a risk of collision?
A1. Compass, radar and visual bearings (visual bearings being the most reliable)

Q2. What scale is your radar(s) on?
A2. 6 and 12 miles.

Q3. Why is your radar on the 12 miles scale?
A3. For early detection of targets.

Q4. You've taken 1 radar plot of a target, would you alter with this plot?
A4. No.

Q5. You've taken a 2nd radar plot of a target, would you alter with this plot?
A5. No.

Q6.Why would you not alter with 1 and 2 plots?
A6. Rule 7 part (c) says not to rely on scanty information, especially scanty radar information.

Q7. What are the dangers with radar plotting?
A7. Time is being wasted and could put your vessel into a collision course.

Q8. If the bearings are steady, is there a risk of collision?
A8. Yes.

Q9. If the bearings are not steady, could there still be a risk of collision?
A9. Yes.

Q10. What situations?
A10. With a large vessel, a long tow or a close quarter situation.

Q11. If plotting a vessel towing a vessel towing another vessel with the length of tow being 2 miles long, what are you going to take bearings of?
A11. The stem of the towing vessel and the stern of the vessel being towed, everything in between is a risk of collision.


Q12. Determine the term "risk of collision"?
A12. Factors:

Distance between two vessels, speed of approach, do courses cross one another


Prevailing circumstances:

State of visibility, traffic & navigational hazards

Q13. What do you understand by all available means appropriate to the prevailing circumstances?
A13. All available means:

Compass bearings or relative bearings

Radar bearings

Plotting detected targets

Background bearings

Foreground bearings

Q14. What precautionary measures shall the master take before proceeding to sea?
A14. Refer to SOLAS Chapter V - Regulation 34.

Before proceeding to sea:

Planning of intended voyage:

Nautical charts, Nautical publications, Organization’s guidelines and recommendations


Identify a route taking account of:

Ships’ routeing systems, Ensures sufficient sea room, Known navigational hazards, Adverse weather conditions, Marine environmental protection

Q15. Summarize the elements to be taken into consideration when planning the voyage.
A15. Refer to IMO Resolution A.893(21)

Q16. Which items should you consider in contemplating a voyage or passage?
A16. Refer to IMO Resolution A.893(21). Para 2.

Q17. Enumerates the factors that the detailed voyage or passage plan should include.
A17. Refer to IMO Resolution A.893(21). Para 3.

Q18. Which factors should the master take into account when executing a voyage or passage plan?
A18. Refer to IMO Resolution A.893(21). Para 4.

Q19. Where should the voyage or passage plan be kept during the voyage?
A19. Refer to IMO Resolution A.893(21). Para 5.

Q20. Discuss the matter of fatigue on board ship.
A20. Refer to MGN 211 (M).