Project Mohole Drilling Platform 



The total forces in these equations are made up of the hydrodynamic forces, the 

 aerodynamic forces, and the propulsive forces. 



HYDRODYNAMIC FORCES 



Forces Due to Acceleration 



The forces that the water exerts on the platform due to its acceleration are 

 given by the formulas that follow: 



^x = "Anil + A22RV + AjgR^ 



Fy = -A22V - AiiRU - A^^R 



M, = -AgeR- A26(V+RU) 



where 



F^ = longitudinal force, positive forward 



Fy = lateral force, positive to port 



M^ = yaw moment, positive when producing yaw to port 



U = longitudinal velocity of vessel relative to water, positive forward 



V = lateral velocity of vessel relative to water, positive to port 



R = angular velocity of yaw, positive to port 



All = added mass for longitudinal acceleration 



A22 = added mass for lateral acceleration 



Agg = added mass moment of inertia for yaw acceleration 



A26 = moment of added mass producing yaw moment due to lateral 

 acceleration. 



Forces Due to Velocity 



General 



These forces are produced by a combination of inertia and viscous effects. 

 It is assumed at the outset that all forces vary as the square of velocity. In 

 order to represent the total force and moment adequately for arbitrary motion 

 of the vessel, it is necessary to consider separately the forces on the various 

 parts of the platform. Where no formula for moment is given, it is calculated 

 by multiplying the forces by the appropriate moment arms. 



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