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Balance of Helm and Static Directional Stability of Yachts Sailing Close-Hauled

Published online by Cambridge University Press:  04 July 2016

John S. Letcher Jr
John S. Letcher Jr*
Affiliation:
California Institute of Technology , National Science Foundation Co-operative Graduate Fellow, Ae. Eng. Candidate, Dept. of Aeronautics
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Summary

An analysis is presented for equilibrium of yawing moments for a yacht sailing in the displacement mode in smooth water. The geometry of hull form and sail plan are quite unrestricted, although special attention is given throughout to currently popular types.

The free-surface flow is simplified by a reflection technique. In cases where the hull form is appropriate, the hull hydrodynamics are treated by lifting-line theory: in other cases slender-body theory is applied. The sail aerodynamics are treated by methods taken from aerofoil theory. Some design charts are given and computation methods are suggested for practical design calculations.

Static directional stability is treated theoretically and some general conclusions drawn regarding the influence of various characteristics on stability.

Where the theory has been applied, results have agreed with the available experimental data within the limits normally provided for adjusting balance of helm. Changes of balance with angle of heel and static stability have been given by the theory at least qualitatively correctly; experimental results are, however, not available for comparison.

Type
Research Article
Information
The Aeronautical Journal , Volume 69 , Issue 652 , April 1965 , pp. 241 - 248
Copyright
Copyright © Royal Aeronautical Society 1965

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References

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