One of the most complicated things to learn about your boat are the COLREGs lights. That stands for International Regulations for Prevention of Collision at Sea. The lights on your boat, both power boats and sail boats, help you navigate at night. They also help other boats understand how to navigate around you. We have rules of the road so it’s easy to understand how your car and the other cars around you work. On the water we have none of that. So you need to rely on these lights to understand nautical rules of the road. Luckily there are nautical mnemonics to help you remember them.

Types of Boat Lights

There are several navigation lights on a boat. All navigation lights must be working and displayed between sunset and sunrise. These will establish the rules of the road for other boaters.

Stern Light: This is a white light that is visible from behind a vessel.

Masthead Light: This is another white light. It is visible from the front and the sides. Any boat that has a motor is required to have a masthead light. If you have a boat that is below 39.4 feet it can be combined with the stern light. This takes the form of one all around white light that can be seen from every angle. If you see a boat that does not have a masthead light, it’s a sailing vessel. Sailing vessels may also have tricolor lights on the masthead. That means red, white, and green. This can only be illuminated when sailing and not combined with other lights.

Sidelights: Sidelights are red and green. They’re visible to boats that are approaching either from the front or from either side. The red light is located on the port or left side of the boat. The green light is located on the starboard or right side of the boat.

Some people have trouble remembering which side is red, and which side is green. Keep in mind the old mnemonic tool that port wine is red. It’s red to port.

Right-Of-Way Rules

Because of the lack of any roadways on the water, the rules of right away can be hard to understand. This is where mnemonics come in.

One unofficial rule of thumb for boaters is that tonnage has the right of way. That means if it comes down to you in your 12 foot boat and a massive freightliner, the bigger boat wins. Always stay out of the way of a larger vessel, even if you believe you have the right of way. This is a simple safety precaution. If there were to be a collision, a larger boat would destroy you in a smaller boat.

If two boats of similar size are approaching one another, then you want to alter your course to starboard. A handy way to remember this is by saying stay to the right and you’ll be alright.

There is an order of priority as dictated by the COLREGS. It will let you know who has the right-of-way in any given situation based on the category of boat. This mnemonic can help you remember it: Generally, Anchoring our Red Tugboat Diligently Minimizes Surge Loads.

General: In general, avoid all collisions. Even if you have the right of way and you see another boat coming right at you, do the smart thing and avoid it if possible. This takes priority over any red lights, green lights, or whatever rule applies. The most important rule is to avoid collisions.

Anchored: Boats that are anchored or more should be avoided by all other boats.

Overtaking: If a boat is being overtaken, it has the right-of-way over the overtaking vessel. This is regardless of whether either boat is powered or a sailboat.

Restricted: A boat with restricted maneuverability has the right-of-way over other boats. That means either fishing, Towing, draft or other reasons.

Traffic: Boats that are part of a traffic separation have the right-of-way over other boats. If you need to cross a traffic lane, cross it at a right angle.

Downriver: On waters where it is applicable, a powerboat heading down river has the right of way. This is over a boat that is heading up river or crossing.

Manpower: This is giving priority to power. A man powered boat such as a canoe has the right of way over a sailboat. That in turn has priority over a motorboat. And a motorboat would have priority over a seaplane. The less powerful the boat, the more priority it will have in terms of right of way. Sailboats may be used to having the right of way on the open water. It’s worth knowing that if you’re in a sailboat you still have to give way to anyone in a kayak.

Starboard: A boat on a starboard tack has priority.

Leeward: If two boats are on the same tack, Leeward gets the right-of-way over Windward.

Light Meanings

The way lights are illuminated can be used to signal other craft about the boat’s condition.

Boat at Anchor: When the boat is at anchor at night, the all-around white light should be lit. There is no clever memory aid rule or mnemonics for this one. It is anchored and has restricted ability to move.

Red Over White Fishing Boat Lights: The red all around light above a white all around lights indicates fishing. Side lights should also be visible. The Stern Light will be illuminated if the boat is in motion. Even if the boat is at anchor, if it’s fishing then anchor lights are not necessary. Red over white fishing tonight is one of the many memory aids or mnemonics used here.

Green Over White Trawling Tonight: Green over white trawling tonight means a green all-around will be above the white all around. Side running lights and of the stern light will also be illuminated, if the boat is making way.

Red Over Red The Boat is Dead: Two red lights one on top of the other indicates the boat is unable to follow any standard rules of the road. It should be avoided. They will not be able to avoid you. Other mnemonics for this are Red Over Red the Captain is Dead. Also the less grim Red Over Red Captain’s in Bed. And finally Red Over Red Captain’s in the Head. The boat is either not under command or not able to follow the rules of the road.

Red Over Green Sailing Machine:  Red over green sailing machine indicates a boat that is not under power. Not all sailboats will use this combination, however. If the boat simply doesn’t have the white masthead light, it is also a sailing boat. Either configuration can indicate a boat that is not under power.

White Over Red Pilot Ahead:  White Over Red Pilot Ahead lets you know that it’s a boat waiting for customers. If you’re looking for a pilot, then you can look here. This display will also be used when a boat is waiting to pick up a pilot done with customers.

White Over White Short Tug in Sight: This display means a short tow, anything under 656 feet or 200 m.


White Over White Over White Long Tug In Sight: In contrast to the previous one, this is anything over 656 feet or 200 m.


Three Reds in a Row No Room Below: You have a duty to keep clear of a boat displaying three reds in a row. This refers to the runner rubbing on rocks or a vessel constrained by its draft. Is experiencing problems and should be avoided.

Red Over White Over Red Restricted Ability Ahead:  This configuration indicates a boat is restricted in terms of maneuverability. It could be servicing underwater cables or pipes. It could be conducting a survey, or it could be moving cargo of some kind. Whatever the case, it’s not in the position to move right away so you have a duty to keep clear.