very low aspect ratio during emergence 

 from a submerged condition to a planing 

 condition. 13 In Figure 8a the float is 

 running in a cavity near the free surface; 

 this is an unstable condition and a small 

 perturbation causes breakdown of the flow 

 over the float to a more stable type as- 

 sociated with planing in which the water 

 is thrown forward and to the sides. From 

 a theoretical standpoint, these two types 

 of flow are closely related. 14 ' 15 > 60 



Figure 7 - Cavity Formed During 



Air-Water Entry of an 



Aluminum Sphere 



Figure 8a Figure 8b 



Figure 8 - TMB Planing Float in the Shape of a Symmetrical Airfoil of 

 Low Aspect Ratio in Submerged and Planing Conditions 



The forward speed of the float is the same in each photograph (see Eeference 15) 



