Determination of Small Craft Leeway
Abstract
Small craft (less than 22 feet) leeway is determined as a function of the wind speed in the range of 5-20 knots to enable more precise forecasting of the leeway drift of a distressed surface vessel at sea. leeway is calculated by measurement of the separation distance of the small craft from a dyed patch of surface water at sea, using time-sequenced aerial photography. Leeway increases linearly with wind speed for small craft equipped with or without a sea anchor in the wind range studied. Leeway for small craft without sea anchor can be calculated from the equation U sub L = 0.07 U sub W + 0.04 where U sub W is the wind speed at 2 meter elevation. Leeway for small craft with sea anchor can be calculated from the equation U sub LD = 0.05 U sub W - 0.12. The small craft drifted off the downwind direction in about 80% of the experiments. The drift angle is variable and difficult to predict.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1974
- Accession Number
- ADA020977
Entities
People
- G. L. Hufford
- S. Broida
Organizations
- United States Coast Guard Research & Development Center