48 



With the moderating of the weather on the morning of April 1, a 

 rectangular search was planned to find the berg sighted in latitude 

 44°21' N., longitude 48°30' W., on March 30, allowing a maximum 

 drift of 40 miles per day for the berg. Before this search was com- 

 pleted a berg was reported in latitude 42°58' N., longitude 48°50' W. 

 This berg was located by the patrol vessel in 42°57' N., longitude 

 48°46' W., and it was identified as the berg of March 30 and had aver- 

 aged for two days 42.5 miles per day. This is an extremely rapid drift 

 and can only be explained as the effect of the northerly gales of March 

 31. Wlien first sighted this berg was of average size, but the above- 

 surface mass consisted mainly of an almost semicircular shell giving a 

 very large surface or sail area per unit mass for the berg. As has been 

 so often stated in the past, this type of berg is most strongly affected 

 by gales, and this berg's drift is further evidence to the fact. When 

 found again after its 2-day drift the berg had diminished considerably 

 in size and two large growlers were drifting in the vicinity. Other ice 

 sighted on April 1 was two small bergs and 10 growlers strung in scat- 

 tered positions along the 50-fathom curve from latitude 44° 10' N., to 

 latitude 43°31' N. The remainder of the patrol was spent following 

 the drift of the above berg, the southernmost ice, as it moved at 0.8 

 knots in a west-southwest direction with the current. Whenever vis- 

 ibility made it worth while the Pontchartrain searched to the westward 

 to be sure no ice got south of the Patrol vessel and to keep track of the 

 many small pieces sighted March 30 and April 1 and 2. By the morn- 

 ing of April 4 all that remained of the berg were two growlers which 

 could not long be a menace to navigation. So at 0647 April 5 the 

 Pontchartrain steamed to the westward toward the relieving point. 



The Tahoe was met in latitude 43°08' N., longitude 52°23' W. A 

 boat was lowered and Lt. G. Van A. Graves, ice-observation officer, 

 and the observer's party were transferred to the Tahoe and at 1555, 

 April 5, 1938, the Tahoe relieved the Pontchartrain as Ice Patrol vessel. 

 The Pontchartrain set course for Halifax, Nova Scotia, arriving there at 

 1150, April 7, 1938. 



The following is a summary of ice and water-temperature reports 

 received during this cruise: 



Number of bergs reported south of latitude 48° north 25 



Number of bergs reported south of latitude 43° north 1 



Number of ice reports received "^ 



Number of vessels furnishing ice reports 26 



Number of water-temperature reports received 1, 164 



Number of vessels furnishing water-temperature reports 139 



Number of vessels furnished special information 12: 



FOURTH CRUISE, "TAHOE," APRIL 5 TO 19, 1938 



The Tahoe sailed from Halifax, Nova Scotia, at 2300, April 3, 1938, 

 for ice patrol. Light variable winds and good visibility were ex- 



