then at 72°06' N, l68°42'W, and travelled northward by motor 

 launch. The northernmost point reached was about 72°14'N 

 latitude. Small floes with occasional hummocking were en- 

 countered in this region. This ice extended 6 to 9 feet above 

 the water and covered from 10 to 25 per cent of the total 

 surface area. Some of the floes were as much as 200 feet in 

 length. These ice conditions extended north to the horizon. 



By reference to the composite ice chart (fig. 52) it will 

 be noted not only that the USS CAIMAN traversed the southern 

 ice limits on 1 August, but also that she made more northerly 

 observations than any of the other ships. A study of the USS 

 CAIMAN'S ice plot indicates that after entering a lead, her 

 most northerly latitude was 72°45'N. This point was almost 

 identical with the southern limit of the arctic pack ice (72°44'N) 

 as reported to the USS NEREUS by aircraft. 



The USS CABEZON traversed the ice limit on 1 August 

 only. The ice plot of the USS CABEZON shows that in the 

 western part of the area investigated the ice limits varied 

 from 71°55'N to 72Q27'N between l69°2l' W and l65°24'W. 



The ice chart of the USS CHUB shows that this ship was 

 travelling continuously in or near the ice from 1 August 

 through 6 August. The USS CHUB was the only ship to re- 

 port on the ice condition in the eastern region extending 

 between longitudes l65°00'W and l6l°35'W. The detailed 

 ice plot of the USS CHUB for 6 August, the day on which the 

 ship traversed this section, shows that the most northerly 

 point attained was 72°26.5' N latitude. The ice observed was 

 classified as one or another of the various sizes from brash 

 to floe ice. While the USS CHUB was leaving the ice area on 

 7 August, a large ice concentration was observed and later 

 described as a "floating island" 



The USS BOARFISH also traversed the ice from 1 August 

 through 6 August. However, her most easterly travel took 

 her only as far as 165°W. Ice plots show the most northerly 

 point to be latitude 72°18' N, longitude 166°48' W. The USS 

 BOARFISH reported a polynya (a sizeable sea water area 

 encompassed by ice), three miles in diameter, at latitude 

 72°17.2'N, longitude 166°49.9'W. In the same region, many 

 glacons that rose as high as 1 5 to 20 feet above the water 

 were observed. Ice observations for 1, 3, 4, and 6 August 

 indicate that brash and floe ice were encountered. 



Variations in the limits of the ice as indicated in the 

 composite ice chart (fig. 52) by the four ships may be attrib- 

 uted not only to navigational difficulties, but also to a differ- 

 ence in interpretation of the ice limits. In some cases a 

 single piece of ice may have been used to define the ice 



