craft to be operated from one side of a wide pond. Open water regattas They take place upon sufficiently large bodies of water to allow a course at least a quarter of a mile in length, which is generally sailed twice or three times over to windward and backward. Triangular courses are also sailed. Racing rules correspond generally to those controlling regattas of large boats, and there is full scope to exhibit all the proofs of good seamanship. The yachts are followed in light skiffs, and may not be touched more than a certain number of times during a race, on penalty of a handicap. Racing measurements differ in the various clubs, but all are based upon length and sail-area. In Great Britain the regular Yacht Racing Association rule has been generally adopted, and handicaps deducted from it. In America models are divided into a single schooner with a maximum load water-line of 63 inches, and three classes of sloops, the first class including yachts with water-lines between 48 and 53 inches, the second class those between 42 and 48 inches and the third and smallest class those between 35 and 42 inches A yacht with a shorter water line than 35 inches must race in the third class. It was previously found that yachts of smaller dimensions possessed too little resistance to the wind. However, model development means that the tiny Footy class - 12 " long and a boat in your briefcase - is now recognised by the Model Yachting Association in Britain and the American Model Yachting Association in the United States as well as being sailed in such countries as New Zealand, Canada, Malta, Sweden, Belgium, Brazil and Denmark. Powered yachts and scale working craft With the advent of radio control it has become much more practical to operate motorized craft. While some are powered by water-cooled internal combustion engines and can be very powerful and fast, the noise and fast operation is discouraged in many park settings as too disturbing to patrons, waterfowl and other wildlife. Electric power and low pressure steam engines are popular, with many amateur machinists building engines from casting kits. Specialized regattas for radio-controlled motorized craft are held that include rubber duck herding and the simulated rescue of ships in distress by a team of operators controlling a pair of tugboats. See also Hobby Ship model Wooden Ship Models Radio-controlled boat