Contributions to planing theory

• Published in: Ocean engineering 1995-10, Vol.22 (7), p.699-729
• Main Author: Payne, Peter R.
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Ground, air and sea transportation, marine construction; Marine construction
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/0029-8018(94)00033-4

It has been known for half a century that the hydrostatic or buoyant force acting on a planing hull in motion is less than Archimedes' force, the weight of the volume of water displaced by the hull, and that this results in the low speed “hump drag” of a relatively deep draft vessel, such as a catamaran, being much greater than the conventionally calculated value. Payne [(1988) Design of High Speed Boats, Volume 1: Planing. Fishergate Inc., Annapolis, Maryland] suggested a reason for this and discussed the various two-dimensional flow analyses of a flat plate planing on a heavy fluid which gave similar results, but did not present experimental data for the phenomena. The omission is repaired in the present paper, together with empirical equations which correlate these data. Some modifications have been made to coefficients employed in the “added mass” equations for planing forces given in earlier papers, as a result of recent research. The modified equations are presented and compared with the available experimental data. It is concluded that the equations earlier presented, as slightly modified in the present paper, agree with the means of 1099 towing tank experiments to within 3%. The experimental scatter for individual experiments was typically ±20% and, for some experimenters, more than ±40% about this mean. It is, perhaps, not generally realized that experimental measurements can be so imprecise. It also seems clear that some experimenters obtained consistently higher or lower lift forces than others under the same test conditions. While the paper cannot claim to be a comprehensive critical survey of all the “classical” planing data, it does attempt to identify some of the anomalous variations between experimenters.