Planing Characteristics of Fast-Water Buoys

Results of an experimental study of the planning of fast-water buoy shapes show that a buoy with a chine that is close to the bottom of the hull will attain a lower planing angle than a buoy for which the bottom-to-chine distance is large. A chine is an edge formed by the intersection of a vertical side and a slanted surface which passes through the water. The planing angle is found to reach a maximum value at an intermediate speed and then decreases as the speed increases, for the buoy with the optimum chine configuration. The planing angle in this case is the counterclockwise angle between the bottom of the buoy and the direction of motion in the vertical plane. A study of the effects of the depth of the mooring cable attachment to the buoy shows that the planing angle decreases with the attachment depth at a given speed. The speed at which the peak value of the planing angle occurs is found to decrease as the attachment depth increases.