Your vessel is crossing the Dover Strait TSS at right angles to the traffic flow. Describe the obligations under Rule 10 and what vessels are exempt.

A. RULE 10 TRAFFIC SEPARATION SCHEMES — CROSSING OBLIGATIONS: RULE 10 GOVERNS TSS USAGE: (1) RULE 10(a): the Rule applies to TSS adopted by IMO and does not relieve any vessel of the obligations under other Rules; (2) RULE 10(b): a vessel using a TSS shall: (i) proceed in the appropriate traffic lane in the general direction of traffic flow; (ii) so far as practicable keep clear of a traffic separation line or zone; (iii) normally join or leave a lane at the termination; (3) RULE 10(c) — CROSSING RULE: "A vessel shall so far as practicable avoid crossing traffic lanes, but if obliged to do so shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow." THIS IS THE HEADING RULE — NOT COURSE. The vessel must cross on a HEADING (the way the bow is pointing) of 90° to the traffic flow — even if the current/wind means the actual track over ground is not 90°; (4) RULE 10(d): an inshore traffic zone may be used by vessels: (a) proceeding to/from a port in the zone; (b) avoiding danger; (c) vessels under 20m or sailing vessels; (5) RULE 10(g): vessels of <20m and sailing vessels may use inshore traffic zones; (6) VESSELS WITH NO EXEMPTIONS: all vessels proceeding in the TSS must follow Rule 10. A supertanker has the same obligation as a 5,000 GT coaster; DOVER STRAIT SPECIFIC: vessels crossing the Dover Strait TSS call Dover Coastguard CNIS (VHF 11) to report; the TSS boundaries are specifically published in COLREG Annex.

B. In the Dover Strait, give way to all vessels in the lanes. Any vessel crossing the TSS is automatically the give-way vessel for all vessels in the lanes.

C. Rule 10 requires vessels to cross traffic lanes on a course at right angles — course made good over the ground must be 90° to the lane direction.

D. Fishing vessels and vessels under 20m are completely exempt from Rule 10 and may proceed in any direction through a TSS without obligation.

A. RULE 8 — CHARACTERISTICS OF PROPER AVOIDING ACTION: RULE 8 APPLIES TO ALL VESSELS in a potential collision situation, regardless of which rules govern the encounter (crossing, overtaking, head-on). The characteristics: (1) EARLY: action taken in ample time — not waiting until close quarters. With 30 minutes to CPA and 10nm, early action is available. Rule 8(a): action shall be taken "in ample time"; (2) BOLD AND SUBSTANTIAL: Rule 8(b): action shall be "large enough to be readily apparent to the other vessel observing visually or by radar." Small incremental alterations (5° at a time) do not meet this standard. The other vessel must be able to see a CLEAR alteration on their radar; (3) POSITIVE: not just an alteration but a committed and maintained course to the clear; (4) RESULT IN PASSING AT A SAFE DISTANCE: Rule 8(d): the action must result in passing at a safe distance. A 0.5nm CPA in busy waters may be adequate; in open ocean — some companies require 2nm minimum CPA; (5) MAINTAIN THE ALTERATION: do not return to the original course until clearly past and clear; (6) AVOID DANGEROUS COMBINATIONS: Rule 8(c): if necessary to avoid collision or to allow more time — reduce speed or take all way off. Speed reduction alone or combined with course alteration is a valid manoeuvre; SPECIFIC CASE (0 CPA, 30 min): Give way vessel should alter significantly to starboard (if crossing, overtaking, or head-on) — aim for CPA of at least 1-2nm and confirm on radar before resuming original course; (7) RULE 8(e): "necessary to pass at a safe distance".

B. Alter course 5° to starboard at once. A 5° alteration is the standard safe minimum under Rule 8 and will be noticed by the other vessel.

C. Wait until CPA reduces to 1nm before altering. Early alteration wastes sea room and may confuse the other vessel about your intentions.

D. Sound five short blasts on the whistle and maintain course. The danger signal is the correct COLREG action when a collision is developing.

A. STAND-ON VESSEL OBLIGATIONS — RULES 16 AND 17: RULE 17 — INITIAL DUTY: the stand-on vessel shall "maintain her course and speed" to allow the give-way vessel to take action. This stability of action allows the give-way vessel to predict the stand-on vessel's position. RULE 17(a)(ii) — MAY ACT: when it becomes APPARENT that the give-way vessel is not taking appropriate action — the stand-on vessel "may take action to avoid collision by her manoeuvre alone." This is a PERMISSION — not yet an obligation. This trigger point is a matter of professional judgement — typically when the stand-on vessel can see that the give-way vessel has not altered AND CPA is becoming dangerously small. RULE 17(b) — MUST ACT: when the stand-on vessel determines that collision "cannot be avoided by the action of the giving way vessel alone" — the stand-on vessel "shall take such action as will best aid to avoid collision." This is the MANDATORY action trigger. At this point — the stand-on vessel MUST act. The action must be: (a) not an alteration to port for a vessel on the port side (Rule 17(c)); (b) bold and substantial; (c) early enough to be effective. SEQUENCE IN THIS SCENARIO: (1) Monitor CPA trend; (2) Sound danger signal (Rule 34(d)) when doubt exists; (3) If no response — consider taking avoiding action under Rule 17(a)(ii); (4) When collision cannot be avoided by give-way alone — MUST act under Rule 17(b); (5) Do NOT turn to port toward a vessel on your port side (Rule 17(c)).

B. As stand-on vessel, you must maintain course and speed under all circumstances until the vessels actually collide. Altering course is always the give-way vessel's responsibility.

C. Sound one short blast and alter to starboard immediately when the give-way vessel fails to respond. This is the correct Rule 17 action.

D. In a crossing situation, the vessel that reduces speed first is always the give-way vessel. Reduce speed without altering course.