Analyses of Mult-iple-Float-Supported Platforms in Waves 



the waterline diameter, while the corresponding full-scale drafts are 

 96 ft and 78ft, respectively. 



Since the full-scale floats are expected to require a hinge to 

 alleviate the bending loads due to wave action on the upper part of the 

 float, it has been decided to simulate these hinges for the present 

 comprehensive test program. The hypothesis that the attenuators will 

 oscillate in harmony under the action of waves will consequently be 

 tested at this early stage. The hinges are made of very flexible sili- 

 cone rubber. 



The attenuators are to be ballasted so that when flooded with 

 water, they have effectively neutral buoyancy and the center-of-gra- 

 vity slightly below the center-of-volume so that a small positive pen- 

 dular restoring moment exists. The attenuators and hinges can be in- 

 terchanged from one row of floats to another. 



Tests in regular waves to determine the heaving motions will 

 be carried out with all possible combinations of floats and attenuators, 

 plus the increased deck stiffness for the intermediate-spacing floats 

 with one of the sets of attenuators. 



An auxiliary investigation will be made of the motions of a 

 smaller array of floats, 10 rows of 10 each, to explore the effect of 

 extent of the array on the interactions. 



Other auxiliary investigations will include a brief study of the 

 effect of externally applied (not from appendages immersed in the test 

 tank) viscous damping for a range of frequencies, including as nearly 

 as possible the heaving natural frequency. Some tests will also be 

 carried out without the yaw restraining spring lines in place. 



Results will be compared with theoretical calculations and, it 

 is expected, sets of interaction coefficients derived. 



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