INTRODUCTION 



Since the early 1960's, the International Ice 

 Patrol Research Section (IIPRS) of the U.S. 

 Coast Guard Oceanographic Unit has used taut- 

 line instrumented arrays to collect current veloc- 

 ity data near tlie Grand Banks of Newfoundland 

 and the Labrador continental shelf. Only the 

 1970-71 projects will be discussed in this report. 



The taut-line instrumented arrays used by the 

 IIPRS (Figure 1) were patterned after a de- 

 sign developed and used successfully by Woods 

 Hole Oceanographic Institution (Berteaux, 1968; 

 Berteaux and Walden, 1969). The arrays con- 

 sisted of a surface float attached to a plaited 

 nylon mooring line with current meters attached 

 at various positions along its length. The com- 

 plete mooring was secured to an anchor with a 

 release device (acoustic or time) which freed 

 the array from the anchor when triggered. 



The direct current observations collected are 

 of interest to the Ice Patrol Research Section : 



• To determine the validity of the geostrophic 

 apjDroximation. 



• To collect direct current measurements which 

 may be used for boundary conditions in a 

 mathematical circulation model of the region. 



• To collect direct current measurements to be 

 used in iceberg drift models. 



The 1970 arrays were set off the coast of 

 Labrador north of the Strait of Belle Isle in 

 positions 54°30'N, 54:°32'W and 54°29'N, 54°- 

 30'W. Both arrays were recovered successfully 

 two weeks after they were set. In 1971, two 

 arrays were set on the southeastern edge of the 

 Grand Banks at positions 45°02'N, 48°55'W and 

 46°40'N, 47°24'W . Two weeks later, one array 

 was recovered; the other array was apparently 

 struck by a fishing trawl which carried away the 

 surface float, allowing the remaining section of the 

 array to sink. When the CGC EVERGREEN 

 was within about two miles of the location where 

 the buoy had been set, the acoustic release device 

 responded when interrogated. Extensive drag- 

 ging operations failed to recover the release or 

 any other part of the array. (Note in proof. 

 Two of the current meters and assorted lengths 

 of line from the southern array were found by a 

 Newfoundland trawler and returned to CGOU 

 in February 1973. The acoustic release was not 

 recovered. ) 



