A vessel is under way when it is not at anchor, not made fast to the shore and not aground. That is the exact definition in the International Regulations for Preventing Collisions at Sea (COLREGS), and it is broader than the everyday sense of “moving”. A boat drifting with sails down and engine off, or hove-to waiting for daylight, is under way even though it is not making way through the water. A beginner can take under way to mean the boat has left its berth and is free of the bottom. An experienced skipper knows the legal distinction matters: the moment you slip the mooring, all the steering and sailing rules apply to you, and you must show the lights of a vessel under way, whether or not you are actually going anywhere. The term is also written as one word, underway, and both forms are in common use.
Under way versus making way
The rules distinguish two conditions that everyday speech blurs. Under way means free of the ground and of any mooring. Making way means actually moving through the water under sail, power or momentum. A vessel can be under way but not making way, for example while drifting, hove-to or stopped with the engine idling in neutral. This matters for lights: a power-driven vessel under way must show sidelights and a sternlight plus a masthead steaming light, but the sidelights and sternlight may be switched off only when the vessel is not under way, that is, when anchored or moored. It also matters for the steering rules. A boat lying stopped in a shipping lane with no sails up is not “anchored” and gains no special privilege; it is a vessel under way that must keep out of the way like any other.
Why the definition matters for collision avoidance
The hierarchy of responsibility in the COLREGS only applies between vessels that are under way. A sailing vessel under way must keep clear of a vessel not under command, a vessel restricted in her ability to manoeuvre and a vessel engaged in fishing; a power-driven vessel under way must additionally keep clear of a sailing vessel. An anchored vessel is outside this scheme entirely: it shows an anchor light or ball and everyone under way must avoid it. So the practical question every skipper must be able to answer instantly is, “am I under way?” If the answer is yes, you have obligations to give way and to keep a proper lookout that do not lapse just because you have stopped for lunch with the sails flogging.
- Under sail alone: you are a sailing vessel under way and enjoy the privileges and duties of Rule 12 with other sailing vessels and Rule 18 with power-driven vessels.
- Motor-sailing: with the engine engaged and driving you, you are a power-driven vessel under way even with sails set, and by day should show a cone point-down forward.
- Drifting or hove-to: still under way. You must keep a lookout and be ready to manoeuvre.
- At anchor, on a mooring or alongside: not under way. Show an anchor light or ball if anchored; the collision rules for vessels under way no longer apply to you.
Getting under way: seamanship
To “get under way” is the traditional phrase for leaving a berth, mooring or anchorage, and it is the moment when most harbour mishaps happen. Good practice is a brief, spoken plan before the lines come off: which way the wind and tide will push the boat, which line comes off last, who has the fenders and the boathook, and where the boat is going in the first thirty seconds. Under sail from a mooring, hoist the main first with the boat head to wind, back the jib to pay the bow off, and slip the mooring when the boat is already moving in the right direction. The boat is legally under way as soon as the anchor breaks out, and so are your obligations.
Frequently Asked Questions about Under Way
Is a boat drifting with no sails up under way?
Yes. It is under way but not making way. It must show the lights of a vessel under way at night and must comply with the steering and sailing rules.
Is it “under way” or “underway”?
Both are used. The COLREGS write it as two words, “under way”, and many style guides prefer that in nautical writing. “Underway” as one word is widespread and understood everywhere.
What lights does a sailing yacht under way show at night?
Sidelights and a sternlight, which on a yacht under 20 metres may be combined in a masthead tricolour, or a combined bicolour on the bow with a separate sternlight. Add a steaming light and switch off the tricolour when motoring.
Under way is the state in which everything a sailor learns about right of way, lights and lookout comes into force, and it begins earlier than most people think, the instant the boat is free of the ground and the shore. Know when you are under way, act like it, and you will be a safer neighbour on the water whether you are racing hard or ghosting home on the last of the breeze.