Motor-sailer crossing a high-speed ferry in the Saronic Gulf
At 22:40 on a clear night in the Saronic Gulf the 24 m motor sailer Thalassa is motor-sailing at 8.0 knots on 090°T, mainsail and genoa set, engine at 1,400 rpm, no black cone displayed. The ARPA shows a passenger catamaran ferry doing 32 knots, bearing 040° on the starboard bow, range 4.5 NM, CPA 0.2 NM, TCPA 7 minutes. A second echo 1.2 NM ahead and slightly to port shows a red light over a white light; it is a longliner hauling its gear. A third echo fine on the port bow at 2.0 NM is a northbound tug showing three red lights in a vertical line, moving slowly along the edge of the deep-water channel. Visibility is good, sea slight, wind NE 3, and there is no traffic separation scheme here. The mate is at the helm; two other crew are asleep below.
1. State the status of each of the four vessels and who must keep out of the way of whom.
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Own vessel (Thalassa). A vessel proceeding under sail and machinery is a power-driven vessel under the Rules. She has no privileged status. By day she must show a cone point downwards (Rule 25(e)); at night she shows the normal power-driven lights only. The missing cone is a defect to correct, not a defence.
Catamaran ferry. Power-driven, underway, in a crossing situation. She sees Thalassa on her own port side, so Thalassa is the give-way vessel (Rule 15) and the ferry is stand-on.
Longliner (red over white). That combination identifies a vessel engaged in fishing other than trawling (Rule 26(c)); a trawler would show green over white. Every power-driven vessel underway must keep out of her way (Rule 18(a)(iii)), and Thalassa must also not impede her – the gear may extend well beyond the hull.
Tug with three red lights. A vessel constrained by her draught (Rule 28). She is not in the Rule 18(a) list, but any other vessel must, if circumstances admit, avoid impeding her safe passage (Rule 18(d)). Because she is working the edge of a deep-water channel, Rule 9 considerations also apply.
Priority of concern: the ferry is the immediate collision risk; the longliner is a keep-clear obligation dead ahead; the tug is a planning constraint on the port bow.
2. What action do you take for the ferry, when, and how do you make it apparent?
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This is a crossing situation with the ferry on the starboard bow and a CPA of 0.2 NM – not an acceptable margin. Closing speed is about 40 kn, so 4.5 NM is only about 7 minutes of reaction time. Rule 16 requires early and substantial action.
Decision point now, at 4.5 NM. Do not wait for the CPA to be confirmed; act at or before about 3.5–4 NM.
Options, in order of preference:
- Alter course to starboard by 30–40° to pass astern of the ferry, and simultaneously reduce speed to about 4 kn. The course change is obvious on radar; the speed reduction buys more margin and lowers the energy if anything goes wrong.
- Pass astern, never ahead. At 32 kn the ferry covers the remaining distance in a few minutes and a yacht crossing ahead is invisible until too late.
Do not alter to port. That turns toward the ferry's track and is the classic collision course error.
Make it apparent: one short blast on the whistle (Rule 34(a) – I am altering course to starboard), monitor the ARPA until the new CPA is confirmed and the bearing draws aft, and be prepared to repeat or to take further action. Wake the skipper, and put a lookout on deck – a 24 m motor sailer is a small radar target to a fast ferry's bridge.
3. At 22:47 the ferry sounds two short blasts and her heading begins to swing to port, toward your bow. Explain the signal, assess the ferry's manoeuvre, and give your immediate actions.
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The signal. Two short blasts means 'I am altering my course to port' (Rule 34(a)).
Why it is wrong. The ferry is the stand-on vessel and has Thalassa on her own port side. Rule 17(b) states that a stand-on vessel may not alter course to port for a vessel on her own port side. Turning to port turns her bow directly into the yacht's track and converts a developing crossing into an imminent collision. It is also the last manoeuvre the give-way vessel would expect.
Immediate actions, in order:
- Five short and rapid blasts on the whistle – the doubt/danger signal (Rule 34(d)) – and a VHF call on 16 to the ferry by name to confirm intentions.
- Hard to starboard and hold speed, or increase speed if that clearly opens the bearing and gets the yacht across and clear of the swinging bow. With a 32 kn catamaran the whole geometry resolves in about a minute – decide once and commit; do not hesitate mid-turn.
- If the bearing still closes, take all way off and be ready to go full astern; a glancing impact at low speed is survivable, a T-bone is not.
- After the incident, record the ferry's name, time, bearing and range, and note the close-quarters situation in the log; report it to the port authority if a genuine risk of collision occurred.