IS IT PRACTICAL TO DESTROY ICEBERGS BEFORE THEY REACH THE SHIPPING LANES?
The Coast Guard has conducted numerous experiments in attempts to determine means for accelerating the disintegration of icebergs. These have included gunfire, mines, torpedoes, depth charges, and bombing. However, the use of conventional explosives or combustibles proves difficult. In addtition to the operational hazards of approaching and boarding an iceberg in a seaway; the theory of explosive demolition shows that a 1,000 lb charge of conventional explosives would be needed to break up approximately 70,000 cubic ft of ice (a growler weighing 1,960 tons) and a hundred such charges would be needed for the destruction of an average berg. Furthermore, to melt a medium-size berg of 100,000 tons would require the complete theoretical heat of combustion of over a quarter of a million gallons of gasoline. Such methods are, of course, economically, as well as practically unsound.
In 1959 and 1960, the Ice Patrol conducted a series of tests using the combustion of thermite. Early experiments by other scientists indicated that thermite, which explodes in ice with an extremely high temperature, would have a thermal "shock" or fracturing effect on icebergs. Ice Patrol experiments demonstrated that, under operational conditions, such was not the case. Natural deterioration remains the most practical process for the elimination of icebergs. Other than through these natural processes, the icebergs prove nearly indestructible. In summary, the following factors affect the longevity of an iceberg and/or the extent of its drift:
- sea ice protection.
- sea state
- water temperature
- and bottom depth
The following is a picture taken during the 1959-60 iceberg bombing experiments.