Navigation Lights


Federal and International regulations require boats to carry lights between sunset and sunrise and during conditions of restricted visibility i.e. fog or heavy rain. The number and color of these lights varies with the size of the vessel. Many commercial vessels carry special lights that identify them to others. This is important because rights of way depend on what type of vessel is involved. Tugs and commercial fishing vessels have the right of way over sailboats which have the right of way over ordinary power vessels. Unique lights are carried by each one.

Let's take a look at the lights a moderate size (23'-65') sailboat carries in different conditions so she will be apparent to anyone approaching. By the way, smaller sailboats and boats propelled by oars should carry these lights also but do not have to. A flashlight, ready to be illuminated, can be a substitute on these small, non-power driven craft. If you would like to read the full set of rules governing navigation lights you can find them here:  You may also read a condensed version, with pictures, for recreational boaters here:

Under sail. Under sail without the engine on, a sailboat displays two sidelights and a stern light. Port sidelight is red with green for starboard. Each shines from straight ahead through an arc of 112.5°. The stern light shines white directly astern through an arc of 135°.

Sailboat with running lights on

Notice in the above illustration if you put all three lights together they would form a perfect circle. We will actually see this when we get to the tricolor light. Moving around the vessel at night you would always see one light and rarely see two at once. The two sidelights at the bow may be combined together into one unit (but still show red and green appropriately) if the vessel is less than 20 meters (65') in length. This uses one light bulb in place of two.

Under power. These are the same lights a power driven vessel would show. In addition to the lights above we add, what the rules call, a masthead light. This masthead light may be at the top of a short mast on a power vessel but is placed about 2/3 the way up the forward mast on a sailboat.

Power vessel running lights on

The masthead (steaming) light is white and shines forward through an arc of 225°. This is the same combined arc of the two sidelights (each at 112.5°). Now, if we were to move around this vessel we would always see two lights from the front; either a red or a green with white over it. Very large vessels (over 50 meters) have two masthead lights; the one you see above and another identical one aft and higher. Note that with both of the above vessels there is only a single white stern light.

Tricolor light. We have the choice to use a tricolor light with these conditions met: Under sail only and less than 20 meters (65') in length.

Sailboat with tricolor light on

Why would we choose to use a tricolor light? Well, the big difference is the consumption of electricity. We power the tricolor light with just one light bulb. Because it must be seen from all around it needs to be at the top of the mast. This is why it cannot be used when the engine is engaged. With the engine on we turn on the masthead light to indicate we are under power but the rules state that the masthead light must be located above the sidelights. Since the masthead light on a sailboat is only part way up the mast this combination doesn't work. So, we can only use the tricolor light on moderately sized sailboats under sail only.

At anchor. Here, we are anchored, or tied to a mooring ball, and must display an anchor light which is a white all around light where it can best be seen. This is usually at the very top of the mast.

Boat with anchor light on

All vessels at anchor must display an anchor light with two exceptions: When in a special designated anchorage and less than 20 meters (65') in length, there is no requirement for this light. Special designated anchorages are not common (as of this writing there are 96 in the US) but may occur where there are large numbers of vessels moored. You will know if the anchorage you are in is so designated by reading the chart where it will be clearly marked. If it's not on the chart then it's not a special designated anchorage by the secretary of transportation. The one other exception to the anchor light rule is for vessels under 7 meters (23') in length provided they are not anchored in or near a channel or where other vessels normally navigate.

Now that we've noted the exceptions to using an anchor light, I must give my own opinion here: Why would anyone ever want to not use an anchor light? Why take the chance a speed boat driven by someone who has had too much to drink will run into you? In Florida there are several deaths a year relating directly to this. I am always amazed, and so are my students, when we anchor with a couple dozen other sailboats and we are one of the few boats displaying an anchor light.

What if your anchor light is burned out? Well, you might make do by turning on lights in the cockpit or hang one in the rigging. In fact, you may use additional lights both navigational and otherwise: "The lights prescribed by these Rules...may be exhibited in all other circumstances when it is deemed necessary". Quoted from the navigation rules.

Fishing vessels. A commercial fishing boat while fishing will show either a red or a green all around light above an all around white light. Sailboats must stay out of their way. Green over white indicates trawling and red over white for other types of fishing.

Pilot boats. These are the smaller, enclosed power driven vessels that ferry the harbor pilot to and from freighters and cruise ships coming in and out of port. They show all around white over red when engaged in their duties.

Tug boats. The lights prescribed vary depending on whether the tug is pushing, towing alongside, towing behind, or in inland or international waters. You will see two masthead lights vertically aligned on the tug and often a yellow light above the stern light. If the tug is towing behind you will also see sidelights and a stern light on the tow. Sailboats must keep clear. Two examples from the Inland rules are below:

Tug showing lights Tug showing lights


Blue Water Sailing School Logo



If you are ready to find out for yourself what it's like to sail a 35-50' boat, receive meaningful sailing lessons, and get a taste of the sea then check out an excellent resource: Blue Water Sailing School. All sailing lessons lead to ASA certification and are taught by experienced instructors who are licensed by the U.S. Coast Guard (Captain's license).