Kim and Mevcier 



centerline. As for the motions tests, wave measurements were made 

 without the float models present for all wave maker settings used for 

 the test program. 



Small Model 



In order to study the effect of model size on hydrodynamic 

 forces, an array of 35 rows of 6 each of smaller scale models was 

 constructed. The scale ratio relative to the larger model was 7/20, 

 corresponding to the ratios of the diameters of the surface piercing 

 tubes, 7/16:5/4. The shape of the floats, similar to that of the large 

 models, was produced by thin- walled wax castings. The damping col- 

 lars at the top of the conical part of the float are stiff mylar film glued 

 to the tube. 



The floats were attached in rows to 30- in wide bars (except for 

 the row used for measuring forces) which were, in turn, attached to a 

 pair of 2"x 4"x5' aluminum strongbacks which were connected to the 

 bridge in the same way as for the large model tests. The spacing ratio 

 and staggered array are the same as for the large model. 



The measurement row of floats was connected to a force ba- 

 lance system for measuring vertical and horizontal wave forces. This 

 row of floats could be moved, as in the tests with the larger model, so 

 that forces in Figure 49 as a function of frequency. Surge force results 

 are given in Figure 50. 



Cross -faired results in the form of carpet plots are given in 

 Figures 51 for heave and 52 for surge force. 



It is interesting to note that the heave force shown in Figure 51 

 does not increase dramatically at the stern as does the heave motion, 

 as shown in Figure 48. 



Small Models 



The force measurements data obtained in the tests in the large 

 tank are presented in the corresponding figures for the large models. 

 Results have been expanded by Froude's Law so that small model data 

 are expressed in large -model-equivalent forces and frequencies. Dif- 

 ferent plotting symbols are used to distinguish small model results 

 from large model results. A composite carpet plot of the heave force 

 is given in Figure 53 for these small model results which are some- 

 what different from the large model results. 



842 



