Two give-way obligations at once off Green Island
It is 1430 on a fine Saturday in October, visibility 8 km, wind south-east force 4. You are coxswain of a 9 m open-cabin motor cruiser making 12 knots on a course of 270°(T), about half a mile south of Green Island, taking four friends from Cyberport to Lamma. Three vessels matter. A high-speed ferry has just left Central and is heading south-west at about 30 knots; she is on your starboard bow at 1.2 nm and steady in bearing. A 10 m yacht under sail, close-hauled on starboard tack, is fine on your port bow at 0.4 nm, also steady in bearing. Astern of you, a Marine Department launch is overtaking on your starboard side. To port lies the edge of a fish culture zone marked by yellow rafts and buoys. Your guests are asking which boat has to give way.
1. Assess the risk of collision with the ferry and with the yacht. Who gives way to whom, and under which rules?
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Risk of collision: in both cases the bearing is steady and the range is closing fast, and Rule 7 says risk shall be deemed to exist if there is any doubt. Do not wait for a bearing to open before acting - against a 30-knot ferry at 1.2 nm you have barely two minutes.
Ferry. She is on your starboard side in a crossing situation, so under Rule 15 you are the give-way vessel and must keep clear. The rule applies whatever her size or speed; her speed only makes early, decisive action more urgent (Rules 8 and 16). A high-speed craft may also be restricted in her ability to alter quickly, which reinforces your duty.
Yacht. She is under sail and you are power-driven, so Rule 18 makes you the give-way vessel to her as well, unless she is overtaking you - she is not; she is on your port bow and crossing.
So you are give-way vessel to two vessels at the same time. That is the point of the question: the duty to the yacht does not disappear because the ferry is faster and more frightening, and the lawful way out is normally speed, not a turn to port across the yacht's bow.
2. What do you actually do with the wheel and the throttle, and why that order?
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Sequence, not one dramatic helm order.
First, reduce speed substantially - off the plane, to idle or to neutral - and take all way off if that is what it takes. This buys time, opens the crossing with the ferry and lets the yacht pass ahead of you. It also satisfies Rule 8: the action must be positive, made in ample time and large enough to be readily apparent to the other vessel.
Second, do not alter to port. A port alteration turns you towards the ferry and, made a little later, puts you across the yacht's bow. Hold your course while the yacht crosses, then, once she is clear ahead, make a bold alteration to starboard to pass astern of the ferry.
Third, aim astern of the ferry, not ahead of her. A give-way vessel that tries to race a fast ship across her bow is gambling on the ship's reaction time and on her not being on a schedule.
Fourth, keep the overtaking launch's problem simple. Rule 13 puts the duty on her, but hold a steady course and speed so she can predict you, and check your starboard quarter before any turn.
3. The ferry sounds five short and rapid blasts and flashes a lamp. What does that mean and what do you do?
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Five short and rapid blasts is the doubt or danger signal in Rule 34(d): the other vessel does not understand your intentions, or believes you are not taking enough action to avoid collision. It is information, not an insult, and it means your plan has not been read from her bridge.
Assume she cannot see you or cannot manoeuvre for you. Immediately reduce speed hard, and stop or go astern if there is room, checking the water astern and to starboard before you do anything dramatic. Let her pass. A 9 m GRP cruiser loses nothing by stopping for two minutes.
Answer on VHF if you have identified her, giving your position, saying that you are taking all way off and will pass astern. Keep the hand-held on 16. Do not reply with more sound signals and do not argue on the radio.
Then start again from scratch: your original plan is void. Re-assess the yacht, the launch and the fish culture zone before you open the throttle, because you have been head-down dealing with the ferry while the rest of the picture kept moving.