Bodensee evening crossing: a yacht on the starboard bow and a Kurschiff on the port bow
You are alone at the helm of a 7.5 m motor cruiser with a 150 hp inboard, crossing the Bodensee on a clear July evening. Your course is 075° true at 14 kn (26 km/h); visibility is about 5 km, and you have GPS, echo sounder and VHF but no radar. At 1.6 km a 10 m sailing yacht, close-hauled on starboard tack, bears 090° true - almost exactly on your starboard beam - and is making 6 kn on a heading of 330°. Her bearing has not changed in two minutes. The wind is 12 kn from 280°. Further out, a 55 m passenger ferry (Kurschiff) is leaving Romanshorn harbour on a course of about 265°, fine on your port bow at 2.5 km and closing. Sunset is in 35 minutes. Your crew is below making coffee, and you would rather hold course and speed because you are expected for dinner.
1. Is there a risk of collision with the sailing yacht? Do the geometry, then state exactly what you do in the next two minutes.
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Risk of collision exists. A steady bearing with decreasing range is the textbook test, and it does not matter that the bearing is almost abeam.
The geometry. Her vector: 6 kn on 330° = 3.0 kn west + 5.2 kn north. Yours: 14 kn on 075° = 13.5 kn east + 3.6 kn north. Relative motion is therefore 16.5 kn west and 1.6 kn north - about 16.6 kn, almost straight across your bow from right to left. At 1,600 m and 8.5 m/s of closing speed she reaches your track line in roughly 190 s and passes only about 150 m ahead of your bow. At 14 kn you cover 150 m in 20 seconds. That is not a margin you want at dusk with no radar and a crew member below.
Who gives way. Two rules point the same way: you are power-driven and she is under sail, and she is on your starboard side. You are the give-way vessel (Rule 15/18).
The action (Rules 8 and 16). Early and substantial, and obvious to her: come back to about 7–8 kn and alter 30–40° to starboard. Turning right swings your bow away from her track as she crosses to port, so you drop astern of her. Do not shave across her bow, and do not make a series of small course changes she cannot read. Then re-check the bearing; if it is still steady, take more action.
2. The Kurschiff now holds a steady bearing, fine on your port bow at 1.2 km. Under the collision regulations you are the stand-on vessel. What do you actually do, and what do the Bodensee rules add?
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Paper position. Under Rule 15 she has you on her starboard side, so she must keep clear; you hold course and speed and she manoeuvres. Rule 17(b) allows you to act the moment it becomes clear she is not doing so - you are never obliged to hold a collision course.
Reality on the Bodensee. The BSO gives professionally navigated vessels (Berufsschifffahrt) priority in the fairway, and sports craft must give them room. A 55 m Kurschiff at about 20 km/h cannot stop in anything like your distance and has a large blind sector ahead of her bow. Insisting on your right of way against a scheduled ferry is the classic way to end up in an accident report.
Practical decision. Take the give-way role: reduce speed and pass astern of her, or hold off and let her cross. Anything that keeps you out of her track and out of her blind sector is correct. Keep your alteration large and early so your intention is unambiguous, and remember your starboard turn to clear the yacht also takes you toward her port side - check both before committing.
Do not assume you have been seen. Small GRP boats disappear against a shore in low sun. If you have her name or the harbour traffic channel, a short VHF call is legitimate; keep a visual watch and a hand bearing until she is past and opening.
3. The sun sets and the yacht is still under way. What lights will you see on her and on the ferry, what must you show, and how does the picture change if she starts motorsailing?
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Sailing yacht under sail, under way. Red and green sidelights, a white sternlight, and no masthead light. At 10 m she may legally carry a single combined tricolour at the masthead instead of separate lanterns - so a single white light high up plus red/green low down is not a motoring vessel.
Ferry. Two white masthead lights in a vertical line (a 55 m vessel), red and green sidelights, white sternlight, and once she has passed you only her sternlight is visible. Two white lights closing head-on at your speed and hers is the cue to check your aspect and turn to starboard early.
Your own lights. Under 12 m you may show an all-round white light and sidelights instead of a masthead light and sternlight, but they must be at the correct heights and not obscured by the crew, a canopy or a fishing rod. No other lights that could be mistaken for navigation lights, and no white light where it will be confused with a masthead light.
If she motorsails. With sails up and the engine driving, she is a power-driven vessel and must show a masthead light forward plus sidelights and sternlight. She loses her sail-driven right of way, the power-versus-power crossing rule applies, and you are still the give-way vessel because she is on your starboard side. The practical consequence: the crossing you judged as a predictable close-hauled track can now change speed and heading under power, so widen the margin rather than reasoning more finely.