Racing Rules of Sailing - Room at the Mark
by Jay Harrell
June 2002

On the open race course, when most of the fleet is somewhat spread out, the basic Right of Way Rules from Section A are pretty much all that is needed to keep things under control when two or three boats come close to each other. On the other hand, at the marks of the course the fleet tends to get very close together again as everyone is trying to be in exactly the same spot on the lake as they round the mark. The “Marks and Obstructions” rules in Section C are designed to deal with the specific situations that tend to occur when sometimes large numbers of boats are rounding a mark or sailing near an obstruction.

The Basics

These rules are necessarily somewhat complex and legalistic. For example, rule 18 has about four times as much text as the entire section on Basic Right of Way, and includes 5 sections one of which has 5 sub-sections. But don’t despair. There are only two fundamental principles:

First, if you are rounding a mark with another boat between you and the mark, you are considered overlapped and have to give the inside boat enough room to maneuver around the mark in a seaman-like way. If the inside boat also has the right of way, you must keep clear in addition to giving room.

Second, if you are clear astern of another boat that is rounding a mark, you have to keep clear and stay out of their way while they round the mark. You are not entitled to any room if you cut inside them.

On a typical triangle race course with port-side mark roundings, these rules tend to come into play in a few specific ways. There are exceptions, but these descriptions cover the most common scenarios for overlapped boats at each mark. Of course, due to wind shifts these same situations can occur at other marks of the course at times.

At the Weather Mark

If two overlapped boats are approaching the mark on starboard tack, the inside boat is also the right-of-way leeward boat and the outside/windward boat must keep clear. The windward boat must also stay far enough away that the leeward/inside boat can mark a smooth controlled turn around the mark without fear of hitting the outside boat. If the inside boat is pointing higher than you, you may be required to tack away to keep clear even if you would fetch the mark if the inside boat was not there.

If two overlapped boats are approaching the mark on port tack, the outside/leeward boat has right of way and must give the inside boat enough room to round the mark including room to tack. However prior to sailing within two boat lengths of the mark (the two-length zone) the leeward boat may have rights to luff the windward boat and prevent them from getting an inside overlap.

If two boats are approaching the weather mark on opposite tacks, rule 18 does not apply and the port tack boat must keep clear. If the port-tack boat tacks within the two-length zone, they do not acquire any of the rights of an inside boat, plus they are saddled with some extra burdens. It’s best to avoid this approach.

At the Gybe Mark

Typically, all boats approach the gybe mark on starboard tack and when boats are overlapped, the inside boat is leeward and also has the right of way. In this case the outside boat must give room and keep clear. This means that the inside boat can swing wide to make a tactical rounding and the outside boat must stay out of the way. Remember that you have to leave enough room for the inside boat to gybe without hitting you with their boom.

At the Leeward Mark

When sailing from the Gybe Mark, typically all boats are on port tack. If two overlapped boats are approaching on port tack the outside boat has right of way, but must give the inside boat room to turn around the mark. The inside boat must make a “seaman-like” rounding and not take any more room than is needed to round the mark.

When sailing a straight downwind leg, boats may approach the Leeward Mark on either tack. If two overlapped boats are approaching on starboard tack, the inside boat is also the right of way leeward boat and the outside/windward boat must both keep clear and give room, including the room needed for the inside boat to turn and gybe the sails. The inside boat is required to go ahead and gybe and not sail past the mark.

If two boats are approaching the Leeward Mark on opposite tacks, the starboard tack boat is both inside and has right of way. In the case the port tack boat must keep clear and allow the starboard boat room to gybe and turn around the mark.

At the Start

There is one very important exception to rule 18. At the starting line, an inside boat is not entitled to room. If two starboard tack boats are approaching the starting line to start the race, and the windward boat can not fit between the leeward boat and the race committee boat, the windward boat must tack away. Remember that a leeward boat has the right of way and at the start line does not have to bear away to give you room even if you are going to hit the race committee boat as a result. Trying to sail in to the start to windward of other boats is called “barging” and is not only against the rules, but is dangerous as well.


An obstruction is any object that you have to sail around to get safely past. Common obstructions include the shoreline, islands, docks, shallow water and sometimes other boats that have right of way over you. The basic rules are the same as they are for marks – the inside boat is entitled to room to safely pass the obstruction even if they otherwise do not have the right of way. When sailing close-hauled, the inside boat can also hail for room to tack and then must be allowed to tack. The list of special cases for obstructions is long and complicated, but fortunately we don’t encounter them very often. Just remember that safety is the primary concern and you can’t run someone into the shore or another boat even of you have the right of way.