Below are ten of the most important rules in sailing. They have been simplified to enable new-comers to sailing to be able to start racing as soon as possible. This should be a starting point on the long road to understanding the complexities of the full Racing Rules. There are many publications explaining the rules in detail.
1. Port/Starboard: A starboard boat has right of way over a port boat i.e. the port boat must keep clear. (A boat is on starboard when its boom lies on the port side).
2. Tacking and Gybing: A boat which is tacking must keep clear of a boat which is not tacking. If you tack or gybe into a right of way position, you must give any boats around you time to react.
3. Windward/Leeward: When boats are on the same tack, the windward boat must keep clear. Also, a boat overtaking another on the same tack must keep clear.
4. Mark Rounding: When approaching a mark if a boat has an inside overlap before the front boat reaches a point within three boat lengths of the mark, it must be given room to pass the mark.
5. Touching a Mark: If you touch a mark while rounding it, you must do a 360 degree penalty turn as soon as possible without interfering with any other boat which is racing.
6. Luffing an Overtaking Boat: If a boat tries to pass you to windward, you may luff right up to head to wind. (but not beyond) However, you must give time for the overtaking boat to keep clear.
When a boat is passing you close to leeward you must not bear down on him. You must sail your proper coarse or higher.
7. Starting: The “inside boat” rule does not apply on the start line of a race. You cannot squeeze between a boat to leeward of you and a mark. If you try, a boat to your lee may luff you and you may not be able to pass inside the mark.
8. Premature Start: If any part of your boat or equipment crosses the start line before the start signal, you must re-start. While returning to the start line, you must keep clear of any boats that are not returning.
9. Avoiding Collisions: You must ALWAYS avoid a collision. (even if you have right of way).
10. Rule Infringement: During any time in the race (including after the Preparatory Signal but before the Start Signal) if you break any of the Racing Rules you may exonerate yourself by completing a 720 degree penalty turn (two turns).