McClure and Hove 



The effect of wind on the platform may be expected to be greater than in the 

 case of conventional ship forms. The large superstructure does result in ap- 

 preciable wind force. Wind tunnel data have been utilized to develop the curve 

 in Fig. 14 which indicates the effect on transit speed of a head wind. These 

 were developed by adding the wind resistance at the relative wind speed to the 

 water resistance and balancing that against the propeller thrust. It will be noted 

 that under trade wind conditions the platform can still maintain a respectable 8 

 to 10 knots directly against the wind. Downwind, of course, the effect is re- 

 versed, but is of a smaller magnitude since the relative velocity is reduced. 



The curve shows that headway can be maintained in winds up to 70 knots. 

 This is not significant since the platform would not normally operate at shallow 

 draft in winds of this intensity. Using positioning units to augment the main 

 propellers the platform can maintain headway under stronger winds. 



ACKNOWLEDGMENTS 



The authors wish to express their appreciation to the many persons who 

 participated in the hydrodynamic studies of the Mohole platform. Of special 

 note are the contributions of Dr. H. K. Beckmann of Rice University in planning, 

 analysis, and interpretation of tests, and Dr. E.G. Holt of Flice University in 

 analysis and programming, including preparation of Appendix D. 



Permission to publish this paper was granted by Brown and Root, Incorpo- 

 rated, and by the National Science Foundation, funding and administering agency 

 for Project Mohole. 



REFERENGES 



1. McGlure, A.G., "Development of the Project Mohole Drilling Platform," 

 Society of Naval Architects and Marine Engineers, November 1965 



2. Kopko, William, "Resistance and Yaw Moments of the Underwater Portion 

 of the Mohole Drilling Platform as Predicted from Model Tests," David 

 Taylor Model Basin Report 1890, August 1964 



3. Michelsen, F.G., and Rabe, N., "Model Tests of Project Mohole Drilling 

 Platform," University of Michigan, Final Report, August 1964 



4. Matthews, J.T., "Low Speed Wind Tunnel Tests of a 1:60-Scale Mohole 

 Drilling Platform Model," David Taylor Model Basin Report, Aero Tests 

 A551, June 1964 



5. Nordstrom, H.F., "Screw Propeller Characteristics," Publications of the 

 Swedish State Shipbuilding Experimental Tank, October 1948 



6. Taggart, Robert, "Analysis of Model Tests," Project Mohole Propeller 

 Design Studies, November 1964 



7. Taggart, Robert, discussion of Reference 1 



430 



