Lights on the Water Aren't Optional
Between sunset and sunrise — and in restricted visibility like fog or heavy rain — navigation lights are how boats see each other and communicate. Without them, a vessel at night is nearly invisible until it's dangerously close. The rules aren't complicated, but understanding them makes you both safer and more readable to other mariners.
Federal law requires navigation lights on all vessels operating between sunset and sunrise and in periods of restricted visibility. Running without lights isn't just illegal — it makes you invisible to other boats, ferries, and commercial traffic that won't see you until it's too late.
The Three Lights on Your Boat
Most recreational powerboats under 65 feet carry three types of navigation lights:
1. The Masthead (or Steaming) Light
A white light mounted at the highest point visible from ahead, showing forward 225 degrees — from dead ahead to just past the beam on each side. On smaller vessels, this is often the forward white light on a combination light fixture at the bow or on a short pole.
Only power-driven vessels show a masthead light. If a vessel is running under sail only, no masthead light — just sidelights and a sternlight.
2. The Sidelights
Red on the port (left) side, green on the starboard (right) side. Each shows 112.5 degrees — from dead ahead to 22.5 degrees behind the beam on each side. When you're approaching another vessel and can see a green light, you're on their starboard side. When you see a red light, you're on their port side.
Memory trick: port wine is red, and port is on the left. Green is the go-signal — starboard is right.
On boats under about 40 feet, sidelights are often combined in a single bicolor lantern mounted at the bow. This is legal and common — it's the same lights, just in one housing.
3. The Sternlight
A white light at the stern (back) of the vessel, showing 135 degrees — centered on dead astern and visible from behind and to each side. When you're overtaking another vessel and approach from behind, you'll see their white sternlight.
The rule of thumb: masthead light (225°) + sternlight (135°) = 360°. Together they cover the complete circle around the vessel.
What Other Vessels' Lights Tell You
Understanding what you're looking at when you see lights on the water is as important as having the right lights on your own boat.
Powerboat Coming Toward You
You'll see two sidelights — red and green together — and possibly the white masthead light. If you see both sidelights, you're looking at the vessel's bow, approaching head-on or close to it. Both of you should alter course to starboard to pass port-side to port-side.
Powerboat Crossing
If you see only a green sidelight, the other vessel is approaching from your port side — they have your vessel on their starboard side, meaning they have right of way and you should give way. If you see only a red sidelight, the vessel is approaching from your starboard side — you have right of way and should hold your course while they give way.
Another Boat Overtaking You
If someone is coming up behind you, they'll see your white sternlight only. An overtaking vessel is always the give-way vessel — they must stay clear of you until completely past.
A Sailboat Under Sail
No masthead/steaming light — just sidelights and a sternlight. If you see a vessel at night with no forward white light, it's likely a sailboat under sail (or a vessel at anchor — see below). Sailboats under sail have right of way over powerboats, so if you're not sure what you're looking at and it shows no masthead light, give it room.
A Vessel at Anchor
An anchored vessel shows an all-round white light — visible from all directions, 360 degrees. On vessels over 50 meters, there are two all-round white lights (one forward, one aft). If you see a white light that isn't moving and doesn't have sidelights or a sternlight, it's likely anchored. Give it a wide berth.
A Vessel in Distress or Special Status
Two all-round red lights in a vertical line means the vessel is "not under command" — broken down or otherwise unable to maneuver. Give it maximum right of way and radio on Channel 16 to see if they need help.
A green-over-white all-round light pattern means the vessel is trawling. Red-over-white means the vessel is fishing with other gear deployed. Both types have right of way over powerboats — their gear restricts their maneuverability.
When Do You Need Lights?
Navigation lights are required:
- Between sunset and sunrise (official sunset/sunrise times, not when it "feels" dark)
- In restricted visibility — fog, heavy rain, or any condition where visibility is reduced
Running lights are not required during daylight hours with clear visibility. But if you're on the water as dusk approaches, turn your lights on early. Other vessels appreciate being able to see you before the light fully fades.
Small Boat Rules
Vessels under 7 meters (about 23 feet) that cannot practically carry the full light configuration may substitute a white electric torch or lantern showing on all sides — basically an all-round white light — as a minimum during emergencies or when proper lights aren't available. This is the legal minimum, not the recommendation. Carry proper lights.
Human-powered vessels (canoes, kayaks, rowboats) operating at night must carry a white light and show it in time to prevent collision. A simple handheld flashlight counts — but carrying it ready to use is your responsibility.
Checking Your Lights Before Dark
Run your lights before you need them — ideally at dusk before it's actually dark. Walk around the boat and verify all three lights are working from the right sides. A burned-out sidelight makes you unreadable to other vessels in exactly the situations where you need to be read clearly.
Carry spare bulbs for any incandescent lights. LED navigation lights rarely burn out but can fail from water intrusion; check them regularly. Our pre-departure checklist includes a lights check as a standard item — use it before every overnight or late-day outing.
Want to test your navigation lights knowledge? The free Skipper Quiz covers light identification scenarios, and the Rules of the Road practice tool lets you drill light pattern recognition at your own pace.