91 



sighted for 24 hours because of fog. A berg may move north, though 

 the flow of the main body of the Labrador Current more often makes 

 it move south. If it goes south very rapidly under the above con- 

 ditions of berg distribution the chances are good that the next berg 

 to the north will take its place in the 60 mile section immediately 

 ahead of the ship. In 24 hours the position of each berg south of the 

 Tail may be assumed to be indeterminate by about 30 sea miles. 

 What is the chance that ice will be hit? 



The breadth of the liner can be neglected, for her maneuvering 

 powers may be such that she can avoid a berg sighted ahead by half 

 the amount of her beam, though if not properly made use of these 

 same maneuvering powers are capable of causing a long raking colli- 

 sion when otherwise the vessel would have just passed clear. The 

 chance that a berg \vil\ be hit works out at 1 chance in 1,200, the 

 ratio between the 300-foot diameter of the bergs and the 60-mile 

 front at right angles to the course line along which each berg was 

 assumed to lie. 



Such chances are not desperate ones, and the}^ would doubtless 

 be welcomed by trans-Atlantic fliers; but the aspect becomes different 

 when it is considered that there are exceedingly many steamship 

 crossings past the Tail during fog and darkness each season and 

 that when bergs are far south they are likely to be spaced much closer 

 than one to every 60 sea miles at right angles to the track. 



Frequent long periods of fog make it impossible to guarantee that 

 occasionally unannounced bergs will not get upon the B tracks. 

 Whether or not there will be disastrous collisions with ice in the North 

 Atlantic depends largely on the speed at which vessels run during 

 thick weather and darkness while they are east, south, and southwest 

 of the Tail. Ships crossing north of the Tail are, as has already been 

 said, liable to meet more and more icebergs in proportion as they 

 cross the Labrador Current in higher and higher latitudes; but their 

 masters realize this and generally run very slowly during low visibility, 

 thereby minimizing the ch-ances of serious damage in the cases where 

 they find collision with ice is unavoidable. 



The above all serves to place some of the problems of the patrol 

 before the reader and shows the inherent danger that lies in neglecting 

 the scouting program for any purpose at all, even that of attempting 

 to make current maps by the hydrodynamic method. So long as 

 there is only one vessel out on patrol at a time, oceanographic stations 

 can be taken here and there without any appreciable interference with 

 the practical program, and this should certainly be done to keep up 

 the annual continuity of the records of salinity and temperature 

 offshore about the Grand Banks. Much useful information and 

 much training in physical oceanography that may be valuable in the 

 future, is given by the occasional scattered stations; but such station 



