Appendix A 



ESTIMATION OF FLOATING PLATFORM 

 STATION KEEPING POWER REQUIREMENTS 



Consider a platform of the following configuration: 



1. Dimensions; 300 ft by 300 ft. 



2. 36 bouyant columns; 20 foot diameter and 100 foot wetted length. 



3. 12 hydrodynamic forms; 20 foot diameter and 100 foot wetted 

 length. 



4. 20 foot spacing from platform to water. 



5. Platform structure height of 20 feet. 



The environmental conditions are taken to be an ocean current of 

 2 knots and a wind velocity of 40 knots. 



The power requirements to maintain station are estimated as: 



Fc V Fw Vw 

 P = -|^ + -j^ = 7700 + 9400 = 17,100 hp 



where F,, = current drag force « 1/2 p Cp AV x 48 



= 1/2 X 1.99 X 1.2 X 20 X 100 x (1.69 x 2)^ x 48 



= 1.27 X 10^ 



Fc ^c ^ 1.27 X 10^ X 1.69 x 2 

 550 550 



Similarly, F„ = wind drag, and 



= 7700 hp. 



^^ Q^ w 1/2 X 0.002378 x 1.2 x (300 x 40) x (1.69 x 40)^ x -^ = 9400 hp, 



55 



