Short answer
At sea, the International Regulations for Preventing Collisions at Sea (COLREGs) apply, supplemented in Sweden by the sjötrafikförordningen (Maritime Traffic Ordinance). The main rules: power gives way to sail, when meeting head-on, both alter course to starboard, when crossing, the vessel that has the other on its starboard side gives way, and the overtaking vessel always gives way. The give-way vessel acts early and clearly. The other holds course and speed but must still avoid a collision.
Who gives way to whom
| Situation | Who gives way | Rule |
|---|---|---|
| Overtaking | The overtaking vessel, regardless of type | 13 |
| Two powerboats meeting head-on | Both, to starboard | 14 |
| Two powerboats crossing | The one with the other on its starboard side | 15 |
| Powerboat and sailboat | The powerboat | 18 |
| Sailboat and fishing vessel or vessel not under command | The sailboat | 18 |
| Vessel in a narrow channel | Boats under 20 m and sailboats must not impede vessels that can only navigate within the channel | 9 |
Two sailboats
- Opposite tacks: the boat on port tack gives way.
- Same tack: the windward boat gives way.
- If you can't tell which tack the other boat is on, give way if you are on port tack.
A sailboat under engine counts as a power-driven vessel, even with sails up.
How to give way correctly
- Assess the risk early. If the bearing to the other boat doesn't change and the distance is closing, there is a risk of collision.
- Make a clear course change, preferably to starboard, or slow down.
- Pass astern of the vessel you're giving way to, not ahead of it.
- The stand-on vessel must still act if a collision can't otherwise be avoided.
Sound and light signals that show intent
The Rules of the Road include short sound signals that show what you intend to do when you see another boat:
| Signal | Meaning |
|---|---|
| One short | I am altering course to starboard |
| Two short | I am altering course to port |
| Three short | I am going astern |
| At least five short | I don't understand your intentions / doubt |
| One long | Approaching a bend where the view is obscured |
Five short blasts from a large ship are a clear warning. Make a clear manoeuvre away from its course. At night, the navigation lights reveal the course: if you see both red and green, the boat is heading straight for you. If you see only red, it is on your port side. If you see only green, it is crossing from port, and you are the stand-on vessel but should be ready to act.
Swedish additions
Under Sjötrafikförordningen (the Swedish maritime traffic ordinance), county administrative boards and municipalities, among others, can impose local speed limits and bans. These are marked with signs and special marks, see navigation marks. Large ships in narrow channels have limited manoeuvrability and can be hard to spot until late. Keep clear in good time and monitor VHF, see VHF channels.
Frequently asked questions
Does a sailboat always have right of way?
No. A sailing boat must give way to vessels engaged in fishing, not under command or constrained by their draught, and an overtaking vessel always keeps clear. In narrow channels, a sailing boat must not impede vessels that can only navigate within the channel.
What are the rules when two motorboats meet head-on?
Both alter course to starboard so they pass port to port.
Do the give-way rules apply on lakes?
Yes, the Rules of the Road apply on all waters navigable by vessels, unless otherwise decided locally.
Does a kayak or rowing boat count?
Yes, they count as vessels under the rules. Rowing boats and paddle craft have little ability to give way, so be considerate and keep your distance.
Sources
- COLREG – internationella sjövägsreglerna, IMO imo.org
- Sjötrafikförordning (1986:300), Sveriges riksdag riksdagen.se
- Sjösäkerhet för fritidsbåtar, Transportstyrelsen transportstyrelsen.se