At 0030 G. c. t. on 20 June, a course was shaped for Cape Spear» 

 enroute to Argentia where the Meyidota arrived on 21 June. 



Weather encountered during this cruise included 166 hours, dur- 

 ing which the visibility was between zero and one-half mile because 

 of dense fog, mist or rain. Of this number, 38 hours occurred during 

 the first half of the cruise and 128 hours during the second half. 

 Less significance is attached to the variation in time than to the 

 variation in locality, since during the second half of the cruise the 

 Mendota was operating in the cold shelf waters most of the time. 

 The periods of low visibility occurred on each of the 23 days of the 

 cruise except 30 and ^1 May, and 1, 2, 6, 7, 9, 11, and 12 June. The 

 lowest air temperature observed was 34° F. on the evening of 18 

 June. The highest winds encountered were force 8 from SSW. on 

 8 June, lasting from 1200 to 1500 G. c. t. Upper air observations 

 included 59 rawins, 1 rabal, 10 pibals, and 47 raobs. Maximum 

 rawin slant range was 161,000 yards. Maximum rawin altitude 

 attained vv^as 18,400 meters. 



Following is a summary of water-temperature, ice and obstruc- 

 tion reports received during this cruise : 



Number of ice reports received 107 



Number of vessels furnishing ice reports 52 



Number of water-temperature reports received 874 



Number of vessels furnishing water-temperature reports 247 



Number of obstruction reports received 



Number of vessels furnished special information 20 



A discussion of the 10 aerial ice observation flights made during 

 the period of this cruise has been included in the description of ice 

 conditions during June. 



Third /ce Observation Cruise, "Mendota," 25 Jane fo 70 Jw/y 7947 



On the morning of 25 June, the Mendota departed from Argentia 

 to search for and stand by a berg which had been sighted by an 

 ice-patrol plane at 45°11' N., 48°26' W., on 23 June. This berg had 

 been drifting rapidly and was sighted again on 25 June by an ice- 

 patrol plane at 43°55' N., 48°58' W. This rapid movement and the 

 prevalence of low visibility in the vicinity made the relocation of 

 the berg difficult and the Mendota searched unsuccessfully from 

 45°11' N., 48°26' W., which position was reached at 1115 G. c. t. on 

 26 June, southward in the area immediately eastward of the Grand 

 Banks to about 41° N., until 1212 G. c. t. on 6 July, at which time the 

 berg was reported by the S. S. William Wheelright at 42°28' N., 

 53°34' W. A course was laid for this position and the berg relocated 

 at 0233 G. c. t. on 7 July at 42°38' N., 53°39' W. Disintegration of 

 the berg proceeded rapidly as the Mendota stood by until relieved 

 by the Spencer at 42°21' N., 54°46' W., at 1216 G. c. t. on 9 July. The 



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