CONCLUSIONS AND RECOMMENDATIONS 
A mathematical model of a craft having a constant deadrise angle, planing in regular 
waves, has been formulated using a modified low-aspect-ratio or strip theory. It was assumed 
that the wavelengths were long in comparison to the craft length and that the wave slopes 
were small. The coefficients in the equations of motion were determined by a combination 
of theoretical and empirical relationships. 
A simplified version for the case of a craft or model being towed at constant speed was 
programed for computations on a digital computer, and the results were compared with 
existing experimental data. 
The comparison of the computed pitch and heave motions and phase angles with the 
corresponding experimental data gave remarkably satisfying results. Comparison of the bow 
and CG accelerations was fair to good. 
In summary, the previously described mathematical model appears to be a valid represen- 
tation of a planing craft in waves for the specific craft geometry and wave conditions 
considered. 
To make the computer program more valuable to the designer the following additional 
work is recommended: 
1. Improve estimates of hydrodynamic coefficients to obtain better acceleration data 
and to include more complicated ship geometry. 
2. Determine added resistance in waves. 
3. Include freedom to surge and to add components of propulsion. 
4. Extend to the case of irregular waves. 
ACKNOWLEDGMENTS 
Acknowledgment is given to Dr. Joseph Whalen and Ms. Sue Fowler of Operations 
Research, Inc., who translated the equations of motion into an operational computer program. 
