Kim and Mercier 



sidewall influences were appreciable. These tests were undertaken 

 after measurements of wave-induced forces were carried out with the 

 same floats, secured to a different mechanism, so the floats and ar- 

 ticulating linkages were completely disconnected and reassembled be- 

 tween the two sets of tests in the two tanks. 



Wave elevation measurements were made at three locations 

 during these tests : a) at a location about 10-ft forward of the "bow" 

 of the platform model and about 1-ft abeam of the model centerline 

 (the bow of the model was situated 35 feet from the wavemaker; b) at 

 a location about 1-ft abeam of the side of the model at its midlength 

 and, c) at a location about 10-ft aft of the model's stern and about 

 1-ft abeam of the model's centerline. Wave measurements were made 

 without the model in the test tank for all wavemaker settings used for 

 the test program so that reference measurements without possible re- 

 flection effects would be available. 



Spring lines were connected to the bow and stern to restrain 

 the model against yawing or excessive drifting. The bow line was 

 connected, through two ordinary rubber bands in series, between the 

 deck of the model and a fixed point at the same elevation about 10-ft 

 forward of the bow. The stern line was connected at the deck and over 

 a pulley about 10-ft aft of the stern, to a 0. 10-lb weight. The light 

 tensions in these lines are considered to exert very little influence on 

 the motions of the model. 



Wave-Induced Forces 

 Large Model 



In order to study the effect of interaction on wave-induced 

 forces to correlate with motions measurements of the articulated mo- 

 del, the same floats used in the motions tests were adapted for use in 

 a restrained model rig. 



The sets of six floats were disconnected from the transverse 

 channels solvent bonded to 1-inch square times 30-inch wide plexi- 

 glas bars. The bars were secured to a pair of 2"x4"xl2' aluminum 

 strongbacks which were, in turn, connected to the bridge spanning the 

 75 -ft length of DL Tank No. 2. The spacing and staggered array of the 

 floats is the could be measured for any desired row of floats. 



Wave elevations were measured at three locations : a) 10-ft 

 forward of the row of floats nearest the wavemaker and about 1-ft 

 abeam of the model centerline (the first row was situated 35 feet from 

 the wavemaker for the small model tests also), b) atalocation 14-in 



840 



