The rules of the road are described in terms of right of way hierarchy in the following figures. Sometimes you’ll see these are listed in opposite order (“A gives way to B” instead of “A has right of way over B”). Since I’m an alpha male, at least when I’m captaining a ship, I find them easier to internalize this way.

Boat Type Hierarchy

The first set of rules, illustrated below, determine which boat has the right of way between different types of boats. For example, sailboats have right of way over motorboats, but not over fishing vessels.

Rules of the Road Hierarchy

Sailboat vs Sailboat

The right of way between two sailboats is determined by the wind and the tack of each boat. Two rules cover most situations. First, a sailboat on a starboard tack has right of way over one on a port tack. The tack, of course, is determined by the windward side of the boat (or alternately, the side opposite the boom). Second, when two boats are both on the same tack, the leeward boat has the right of way. Other situations arise, and are described in the figure, but these two rules cover most encounters.

Rules of the Road for Sailboats

Powerboats

When two boats under motor cross paths, the right of way is determined according to stand on and give way zones. These zones match lighting requirements, but they also apply during the day. The idea is simple. If you see a red light (or the red zone of a boat during the day), give way. If you see a green light, stand on. Two boats will never see green if they’re on a collision course.

Stand on and Give Way Zones

The elegance of this system is that you only need to worry about what you see in front of you. You don’t need to go through an elaborate logical process like, “OK, the other boat is pointing at my starboard bow, which is in my green zone, therefore he is going to stand on, so I need to give way.” Instead, you just look at the other boat. Do you see green or red? That’s all you need to know. You do, however, need to know the zones during the daytime even without the aid of lights, as mentioned earlier. Also, if you see the white zone, it means you are overtaking the other vessel, and need to give way.

When two boats meet exactly head on, they should determine their actions through sound signals, as discussed later, but the convention is that both boats turn to starboard.