McClure and Hove 



173 



178 



168 



75 



105 



193 



930 



1400 



17.5 



1,300,000 



970 



2700 



52.5 



Aerodynamic drag coefficients: 



Angle C13S C^S 



14,500 



45 22,500 7500 



90 18,000 1000 



135 22,500 -7500 



180 14,500 



Appendix D 

 MOHOLE DYNAMIC POSITIONING SYSTEM 



GENERAL DESCRIPTION 



The positioning system consists of three sonar reference subsystems, a 

 two-channel analog positioning computer, display and motor control components, 

 gyrocompass subsystems, and special purpose power supplies. 



The subsystems include independent parallel channels capable of providing 

 desired positioning information to the positioning computer or to the pilot, for 

 manual control. Paralleling of all subsystems not only provides cross-checks 

 on position information and control, but also makes possible trouble-free posi- 

 tioning when routine maintenance or component failure requires the subsystem 

 to be shut down. 



To meet the performance and maintainability requirements, each of the 

 three reference subsystems is further paralleled or provided with standby ele- 

 ments to permit rapid changeover in the event of a failure. 



In addition to the fully automatic mode of operation, several fall-back or 

 emergency modes are provided which require various degrees of manual control. 



442 



