From a weather forecasting viewpoint the situation of the sailing yacht at sea is unique. The yacht is small and entirely dependent on one meteorological element, wind, for its motive power. It is a device where an increase in that power increases the safety factor of speed by a very small margin while at the same time it increases the danger factor to a much larger degree. This is mainly because the increase in wind speed is accompanied by wave building and the latter increases with wind speed, time and, very dangerously, with approach to the shallow water that must often be traversed before safety is gained. It is not only wind speed that puts yachts in danger, but the combination of wind speed and attendant seaway. However seaway is not an element predicted in weather forecasts; it is a branch of seamanship left entirely to the skipper on the spot.