development was disseminated to maritime interests via the ice 

 broadcasts. It is significant that the navigability of the strait at 

 such an early date is almost without precedent. 



The absence of the ice patrol cutters from participation in the 

 season's activities plus the rotation of one PBIG aircraft between 

 Argentia and its home base helped keep operating expenses of ice 

 patrol to a minimum. 



The oceanographic program was conducted, as in recent years, 

 by the Coast Guard Cutter Evergreen. Three oceanographic 

 cruises and one post-season cruise were made and are discussed 

 in detail elsewhere in the bulletin. 



AERIAL ICE RECONNAISSANCE 



The entire ice observation service was conducted by two winter- 

 ized PBIG (converted B-17) aircraft without support from the 

 ice patrol cutters. As already mentioned, the absence of any 

 threat to the established shipping lanes permitted a rotation of 

 aircraft between Argentia, Newfoundland, and the home base of 

 Elizabeth City, N. C. Flight plans were usually about 1,200 

 miles in length (8 hours) with flight lines 25 miles apart. It 

 was rare, even under the most ideal weather conditions, to find 

 the entire search area free from fog so that it was necessary 

 to rely on a radar search whenever visibility was restricted. 

 Loran, with readings taken every 3 minutes, was the most effec- 

 tive tool at the navigator's disposal which, with the aid of celestial 

 navigation, made it possible to pinpoint continuous fixes, the maxi- 

 mum error rarely being more than a few miles. A trained ice 

 observer, responsible for defining and plotting all ice sighted, was 

 carried on each flight. Since there was little ice of any conse- 

 quence south of latitude 50°00' N., most of the 27 flights were 

 conducted between latitudes 50°00' N. and 55°00' N., and several 

 flights searched along the Labrador Coast as far north as 60°00' 

 N. The total hours in flight for both aircraft was 198.2 hours, 

 cruising 29,808 miles and searching 600,790 square miles. The 

 average duration of a flight was 7.3 hours, although individual 

 flights ranged from 2.5 hours to 10.5 hours. Only 139 bergs were 

 sighted. A policy of waiting for favorable weather before dis- 

 patching a flight contributed to the efficiency of each flight and 

 made for good visual effectiveness. Flights were made about 

 twice a week, the greatest interval between flights after the for- 

 mal inauguration of ice patrol services being 7 days. 



COMMUNICATIONS 



Since the success or failure of an ice observation service is 

 directly dependent on the efficiency of the communications tech- 



