During the period of this cruise surface patrol vessel activity 

 was supplemented by aerial ice observation flights as follows : On 

 18 April two flights covered the area from 41° N., to 44° N., be- 

 tween the 51st meridian and about longitude 47° 30' W., and from 

 44° N., to 45° N., from the Grand Banks eastward to about 45° 45' 

 W. Weather did not permit aerial reconnaissance of the critical 

 area again until 29 April when one flight covered the area be- 

 tween 43° and 45° N., from 43° to 46° W., and a second flight 

 covered the area between 51° W., and 47° 15' W., from 40° 15' N., 

 to 41° 45' N. On the following day one flight extended this searched 

 area northward to 43° N., and added a 50-mile wide strip along the 

 southwestern edge of the Grand Banks westward from the Tail 

 of the Banks to the 53d meridian. The same day a second flight 

 covered the southern edge of the field ice from 49° N., to 50°15' N., 

 between the Newfoundland coast and 48° 15' W. 



Fourth Croise, "Tampa," I May to J5 May, 1946 



The Tampa departed Argentia, Newfoundland, at 1336 G. c. t. 

 on 30 April 1946, for ice patrol. The Modoc was met and relieved 

 as surface patrol vessel at 45°00' N., 50°55' W., at 1100 G. c. t. on 1 

 May 1946. 



Weather during this cruise may be summarized as follows : Fog 

 was scattered throughout the period for a total of 105 hours. It 

 varied in density but was generally moderate to dense, restricting 

 visibility to a half mile or less. Precipitation occurred in the form 

 of light rain and light drizzle. There were approximately 15 hours 

 of precipitation, the longest continuous period being 6 hours. There 

 were no marked changes of barometric pressure of any significance. 

 The highest recorded pressure was 1,028 millibars and the lowest 

 1,007 millibars. The maximum wind was force 7 and came from 

 the northwest and westnorthwest. Seas were generally smooth, 

 with low average swells. The highest state of sea was 5 and oc- 

 curred during the period of maximum wind. This was on 5 May. 

 Air temperatures varied from a minimum of 31 °F. on 6 May to a 

 maximum of 62 °F. on 14 May. 



On 15 May, 1946, at 0920 G. c. t., at 45^00' N., 50^51' W., the 

 Modoc relieved the Tampa which then set course for Argentia, 

 Newfoundland, arriving there on 16 May. 1946. 



The following is a summary of the water temperature, ice, and 

 obstruction reports received during this cruise : 



Number of ice reports received 11^ 



Number of vessels furnishing ice reports 66 



Number of water-temperature reports received _ - 849 



Number of vessels furnishing water-temperature reports 16o 



Number of obstruction reports received ^ 10 



Number of vessels furnished special information 30 



136 



