COLREGS — rules of the road
The International Regulations for Preventing Collisions at Sea (COLREGS) — plain English quick reference for recreational sailors and boaters.
Related reference
Who has right of way — the hierarchy
Vessels higher in the list must be given way to by those below them.
Note: a sailing vessel using its engine is treated as a power vessel regardless of sails.
Crossing situation (Rule 15)
When two power vessels are crossing, the vessel that has the other on its starboard (right) side gives way.
- Give way if the other vessel is on your starboard side — you see their red port light
- Stand on if the other vessel is on your port side — you see their green starboard light
- Give way early and obviously — alter course to starboard, pass behind the other vessel
Memory: “if to starboard red appear, ‘tis your duty to keep clear”
Head-on situation (Rule 14)
When two power vessels meet head-on, both vessels alter course to starboard to pass port-to-port.
- Both vessels turn right — you pass each other on your left (port) sides
- If in any doubt whether it is head-on, assume it is and turn to starboard
- One short blast on the horn signals your intention to turn to starboard
You see both red and green lights — or masts in line — head-on.
Overtaking (Rule 13)
Any vessel overtaking another is the give-way vessel, regardless of sail or power.
- Overtaking applies when approaching from more than 22.5° abaft the beam
- In practice: if you can see the other vessel’s stern light, you are overtaking
- The overtaking vessel must keep clear until fully past and clear
Rule 13 overrides Rule 12. Even a sailing vessel overtaking a power vessel must give way.
Sail vs sail (Rule 12)
| Situation | Give way | Stand on |
|---|---|---|
| Different tacks | Port tack vessel | Starboard tack vessel |
| Same tack, overlapping | Windward vessel | Leeward vessel |
| Overtaking | Overtaking vessel | Vessel being overtaken |
A vessel is on starboard tack when the wind comes from the starboard side — the boom is to port.
Narrow channels and traffic separation (Rules 9 & 10)
- Keep to the starboard (right) side of a narrow channel
- Small vessels must not impede vessels that can only navigate safely within the channel
- Sailing vessels must not impede power vessels in a narrow channel
- Do not cross a traffic separation scheme if you can avoid it; if you must, cross at right angles
- Vessels using a TSS lane keep to the starboard side of their lane
Restricted visibility (Rule 19)
- Proceed at a safe speed — be ready to stop
- If you hear a fog signal apparently forward of your beam — reduce to minimum steerage way or stop
- The crossing, head-on and overtaking rules do not apply in restricted visibility
- Sound signals in fog: power vessel underway — one long blast every 2 minutes; sailing vessel — one long + two short every 2 minutes
Action to avoid collision (Rules 8 & 16)
- Take action early — a small alteration early is better than a large one late
- Make it obvious — alter enough that the other vessel can clearly see your intention
- Do not make a series of small alterations — one clear, large alteration
- If collision is imminent, both vessels must take whatever action best avoids collision
Quick reference — who gives way?
| You are | Other vessel is | You must |
|---|---|---|
| Power | NUC / RAM / Constrained by draft | Give way |
| Power | Fishing (gear deployed) | Give way |
| Power | Sailing (no engine) | Give way |
| Sailing | NUC / RAM / Constrained / Fishing | Give way |
| Sailing (starboard tack) | Sailing (port tack) | Stand on |
| Sailing (port tack) | Sailing (starboard tack) | Give way |
| Sailing (leeward) | Sailing (windward, same tack) | Stand on |
| Overtaking (any vessel) | Any vessel being overtaken | Give way |
| Power (other on your stbd) | Power (crossing) | Give way |
| Power (other on your port) | Power (crossing) | Stand on |
| Power or sail | Head-on power | Turn to starboard |
| Small vessel | In narrow channel / TSS | Do not impede |