ExtensiA^e experiments have been pursued by the Ice Patrol to 

 discover a practical means of iceberg destruction. High explosives 

 (TNT mines) and gunfire have been tried repeatedly with in- 

 different results. The experiments of H. T. Barnes (1927) in berg 

 destruction have been followed by the Coast Guard with great inter- 

 est. Barnes has shown, undoubtedly, in his work with icebergs, St. 

 LaAvnmce field ice, and river ice jams that the high temperature 

 radiations produced by his thermit charges do have an impressive 

 disruptive effect on ice. It was therefore hoped that this method 

 might prove valuable in the destruction of isolated bergs, particu- 

 larly those drifting well south, immediately in the path of the trans- 

 Atlantic express lanes. The effective placing of the thermit charge, 

 however, necessitates boarding the iceberg. Barnes carried out his 

 interesting experiments on icebergs in the sheltered water of Notre 

 Dame Bay near Twillingate, Newfoundland. These bergs were 

 either grounded or at least in comparatively stable equilibrium and 

 the water surrounding them was smooth and protected. Even under 

 these conditions Barnes thought the equilibrium of a berg, some 12 

 hours after a thermit charge had been set off, so uncertain that he 

 considered it unsafe to board it again to try the effects of a second 

 charge. The conditions in the open ocean are far less favorable for 

 boarding icebergs. The heavy ocean swell, even on the calmest days, 

 is continually breaking against the precipitous sides or foaming over 

 outlying ledges. Coupled with the motion of the sea is the fact 

 that those bergs it is desired to destroy are almost invariably in 

 warm water, which makes their equilibrium extremely delicate. To 

 approach such an object and go aboard it from a small boat in the 

 open ocean seems an unw^arranted risk of life. This is especially 

 true when it is considered that these southernmost bergs have an 

 extremely limited life span remaining (7 to 10 days) and unless the 

 berg was completely disintegrated on the first try its life would only 

 be shortened by 1 or 2 days (Ricketts, 1930, Bulletin No. 18). 



Too much credit cannot be given to those officers of the Coast 

 Guard who conducted tlie first International Ice Patrols in 1913 and 

 1914. It was due to their immediate grasp of the situation, intelli- 

 gent interpretation of conditions and low percentage of erroneous 

 conclusions that all these many problems outlined in this section were 

 quickly realized and vigorously attacked from the very beginning. 

 Tlie solution of these problems has been the aim of the Ice Patrol 

 over its entire 22 years of service. The lines of investigation which 

 showed no definite results after a fair trial were quickly dro})|)ed and 

 those that gave results were kept, and carefully studied. 



The International Ice Patrol, as at present organized, is carried 

 out by three vessels. Two of these vessels carry on the actual patrol. 



