Offshore racing is for large keelboats or multihulls and generally involves a fleet of yachts or large multihulls racing from one city to another. Some of the most famous offshore races are the Sydney-Hobart Yacht Race, the Fastnet race and the America's Cup.
Harbour racing is usually enjoyed by sailors of keelboats, dinghys, catamarans, skiffs, sailboards... Most racing of this type is on triangular courses of about one nautical mile on each side, and consists of several laps. Olympic sailing is of this type.
Harbour racing can be futher subdivided into two categories: One-design and not one-design. In one-design all boats entered in a race must conform to the same standard (class rules ). In this way the boats are as identical as they can be manufactured, thus emphasizing the skill of the skipper and his/her crew. Examples of classes currently active are: Snipes, Stars, Thistles, Lightnings, Lasers, J/24, etc. Each class has a detailed set of specifications that must be met for the boat to be considered a member of that class. At important regattas the boats are measured prior to the event to insure that they do conform.
When all the yachts in a race are not members of the same class, then a handicap is obtained. The handicap attempts to specify a "normal" speed for that boat. In perfect world, after applying the handicap each boat would have the same finishing time if each was sailed equally well. However, it is difficult to obtain one number,the handicap, that equiably covers all conceivable sailing condition, Still a handicap is used to determine how the boat finish. Each boat is timed over the specified course. After it has finished, the handicap, is added to each boats finishing time. The results are based on this sum. The boat with the smallest time + handicap is the winner.