50 



gave an opportunity to observe the performance of these floats as well. 

 These trials are described in the following section. 



PROCEDURE IN PULL-SCALE SWEEPING OPERATIONS 



Pull-scale observations of the performance of the TMB planing float 

 and of the NMWTS float were made on 11 March ^^kk at the U.S. Naval Mine War- 

 fare Test Station, Solomons, Maryland. In these tests twenty planing floats 

 were used in conjunction with seven cylindrical floats on a single cable. 



Although the original specifications called for the use of 18OO 

 feet of aluminum cable having a negative buoyancy of 0.55 pound per foot, 

 the trials discussed herein were made with 2000 feet of copper cable weigh- 

 ing 0.83 pound per foot in water. With a spacing of 75 feet between floats, 

 each float was carrying approximately 63 pounds. 



The arrangement used in the full-scale tests is shown schematically 

 in Figure 39 • Runs were made with the two Identical towing ships separated 



Cylindrical Float 



Method of Securing Floats to Sweep Coble 5 Cylindricol Floats- 



Junior iVIInesweeper- 



Plgure 39 - Catenary-Type Sweep Towing Arrangement for Tests of 11 March 19^4 



by 350. ^00, 450, and 5OO yards. Observations were made at speeds up to 5-25 

 knots. Ship separation was measured by a stadimeter, and speeds were computed 

 from taf frail-log readings. The total tension in the catenary-sweep cable and 



