Navigation rules and collision avoidance (COLREG / inland waterway rules)
Theory questions here come from the COLREG (International Regulations for Preventing Collisions at Sea, 1972) as applied on Swiss waters, supplemented by the Binnenschifffahrtsverordnung (BSO) and lake-specific rules such as the Bodensee-Schifffahrts-Ordnung. The exam tests whether you can name the give-way vessel, state the manoeuvre, and spot the case where both vessels must act.
The priority ladder
- Power vs power: crossing - give way to the vessel on your starboard side; head-on - both alter to starboard; overtaking - the overtaking vessel keeps clear.
- Power vs sail: power gives way, unless the sailing vessel is overtaking or is motor-sailing (day shape: cone point down; at night, power-vessel lights).
- Sail vs sail: port tack gives way to starboard tack; same tack - the windward boat gives way. If you cannot tell the other's tack, give way.
- Ranked above ordinary power craft: not under command (two red all-round lights), restricted in ability to manoeuvre, fishing, towing.
How to give way properly
Act early and substantially: a course change of at least 20–30°, or a clear reduction in speed, made in good time so the other skipper can read your intention. Do not cross ahead. The stand-on vessel keeps course and speed but must still act if the give-way vessel does not (Rule 17). A steady relative bearing means risk of collision; a changing bearing means you will pass clear.
Swiss and inland additions
Scheduled passenger vessels and ferries have poor manoeuvrability and long stopping distances: do not cut across their path or pass close ahead. Keep to the starboard side of narrow channels, do not anchor in fairways, and drop to a no-wake crawl near harbours, moorings and swimmers.
Worked example
Two motorboats approach at 90°. From A's helm, B is 30° on the starboard bow and the bearing is not changing. A is the give-way vessel because B is on A's starboard side. Correct action: A alters to starboard, sounds one short blast, and passes astern of B, while B holds course and speed. Had A turned to port, it would have cut across B's bow and created a close-quarters situation.
Traps
- Saying 'I had right of way' - the rules never grant an absolute right; both vessels must avoid collision.
- Forgetting that an overtaking vessel stays give-way even if it is a sailing boat or the faster craft.
- Misreading the stand-on duty: it must act when collision cannot be avoided by the give-way vessel alone.
- Missing the cone that shows a yacht is motor-sailing.