Marine Technology - January 2007 - Page#81

<BODY> <span id="lblContents">Fig. 2 Underwater photograph showing arrangement of tufts over bottom illustrating direction of fluid flow Fig. 3 Characteristic features of vee-bottom planing surface. (A) model of wedge; (B) transom; (C) keel; (D) chine; (E) whisker spray; (F) reflection of spray; (G) spray root region Using the above definitions of the various parameters, it can be shown that the total whisker spray area (two sides of the hull) projected on the plane through the keel and perpendicular to the hull centerplane is equal to: As = b2 16 sin 2 The actual wetted area in the plane of the bottom surface of the hull is: Aas = Thus, Aas = b2 4 sin 2 cos (7) As cos tan tan (4) Using the previous definition of , it is seen that: tan = 2 tan tan (5) Substituting into equation (4), As = b2 4 sin 2 (6) This rather simplified expression for spray area is somewhat different from the complicated equation given in Savitsky (1964). In that reference the spray area is taken as that projected on a plane through the keel and perpendicular to the hull centerplane. In the present development the spray area is defined in the plane of the bottom (which is realistic). Further, in Savitsky (1964), the oncoming fluid, which creates MARINE TECHNOLOGY 38 JANUARY 2007</span> <br /> <br /> <a href="http://www.digitalwavepublishing.com/" title="Digital Magazine">Digital Wave Publishing</a> </BODY>