Ill 



4. OBSERVATIONS ON ICEBERG DISINTEGRATION SOUTH OF THE 

 FORTY-FOURTH PARALLEL 



One might assume that the ice patrol as now conducted has more 

 frequent and better opportunities actuall}^ to observe the disinte- 

 gration of icebergs and field ice than is the fact. There are some 

 opportunities for first-hand observation, of course, but these are often 

 not so good as might be \\dshed. For instance, during the writer's 

 four years' experience with the ice patrol he has never seen a single 

 square foot of the field ice that is so abundant during the earlv season 

 in the northern parts of the Grand Banks region. The reason for this 

 is that the patrol must almost always remain close by the southern- 

 most ice limits. About these limits the field ice is not usually found, 

 and even the bergs themselves are rather few and far between. 



Frecjuently after a day of searching a berg reported earlier by a 

 passing vessel is found late in the afternoon after the completion of a 

 predetermined search pattern. It is usually given a berth of from 

 one-half to one-fourth mile, though sometimes it is passed closer, 

 depending upon weather and other conditions. The ship will then be 

 stopped 1 or 2 miles to leeward of the berg, where it is ''secured" 

 for the night — that is, steam is turned off the propelling machinery 

 and the larger generators and auxiliaries, to save fuel for future 

 searches for ice. 



When daylight returns next morning the berg is usually only a 

 small white mass on the horizon. It may even be 8 or 10 miles to 

 windward, on account of the relatively greater effect of breezes on 

 the ship and surface water than on the deep-lying berg. It may be 

 approached again before the new day's search is started, but in many 

 cases it is onh^ relocated from a distance by a series of bearings taken 

 with the aid of the gyrocompass repeaters on the wings of the bridge. 

 Such bearings can locate the geographical position of the berg as well 

 as steaming up to it, and the}^ can be taken while the ship is running 

 along on a set of courses planned to make the new day's search for 

 ice most effective. 



Possibly the patrol will return to the old berg for the night, and if 

 this is done, a comparison can be made with the way the ice looked 

 24 hours earlier. But new bergs that require watching may be found 

 in more threatening positions than the old one, and if this is the case, 

 the former may never be seen again. 



Each season a few of the most southern bergs are watched during a 

 period of days. Then the usual procedure is to drift well clear of the 

 ice and to run up toward it once or twice a day, in the evening, or 

 both morning and evening, depending on the rate at which the patrol 

 ship is drifted or blown away. 



During about one-third of the ice-patrol season fog makes all con- 

 tinued observations of ice impossible. Bergs under surveillance when 



