High Performance Ships—Promises and Problems 15 
/ 
DESTROYER / 
HORSEPOWER 
SHARK FORM 
SPEED 
Fig. 14. Speed-power curves of a destroyer and the 
shark form 
(+) BOW UP 
SHARK FORM (ISLAND AFT) 
fe) 
MOMENT COEFF 
FROUDE NUMBER 
Fig. 15. Comparison of the pitching moment for the shark form with Rankine 
ovoids, with the hull 1.5 diameters below the surface 
appear comparable. The pitching moments are not small and will probably require large 
control surfaces to counteract them. In view of the fact that the moments vary in direction 
and magnitude with speed, the control surfaces may have to be controlled by an autopilot 
system. 
