Sail Number

A sail number is the identifying number, usually with a class symbol and a national letter prefix, displayed on a racing boat’s mainsail (and often the spinnaker). It lets race officers and competitors tell boats apart on the water and in results. World Sailing assigns national prefixes (GBR for Great Britain, USA for the United States) and class rules set the symbol and digit height; the layout is fixed by Appendix G of the Racing Rules of Sailing. One-design classes number boats sequentially, so the number also records when a hull was built.