Applications in Peace and War 



17 



em North Atlantic, as shown by comparison 

 of cnrrents with the observed tracks of 

 icebergs. The United States Coast Guard, 

 which operates the International Ice Patrol, 

 now computes currents from detailed tem- 

 perature and salinity observations each sea- 

 son to predict the probable number and 

 location of dangerous icebergs in the West- 

 ern North Atlantic. 



In the days of sailing ships, knowledge 

 of the direction and speed of major ocean 

 currents far from shore was useful in short- 

 ening the time required to sail from one 

 port to another. With the development of 

 faster vessels, less advantage was taken 

 of currents because they represented only 

 a small fraction of the speed of the ship. 

 Recently, however, it has been shown that 

 in certain areas major ocean currents, such 

 as the Gulf Stream, are much narrower than 

 had previously been supposed and flow at 

 greater velocities, up to seven knots. If 

 such high speed jets in the ocean can be 

 readily located, considerable advantage is 

 to be had even for large, fast ships. 



The development of air travel over the 

 ocean has increased the necessity for de- 

 tailed current information on the high 

 seas in order to locate survivors from trans- 

 oceanic planes forced to ditch at sea. Meth- 

 ods for locating survivors on life rafts at 

 sea developed during the last war were 

 based on the best estimates then available 

 of the surface currents and the effects of 

 winds on these currents and on the rafts. 

 The location of survivors on life rafts is 

 facilitated if a reliable means of communi- 

 cation between survivors and searching 

 parties is available. Underwater sound 

 (SOFAR), trapped in a water layer or 

 "sound channel" and transmitted for great 

 distances, may be used for this purpose. 

 Stations have been established in the Pa- 

 cific to locate by triangulation the source 

 of sound produced in this "channel" by 

 the detonation of bombs dropped by sur- 

 vivors. 



In the past the icy wastes of the Arctic 

 Sea have been avoided by all but a few 

 explorers, but in future it can be expected 

 that this area will be more and more trav- 



eled bv ships and aircraft. Knowledge of 

 the movement, strength, thickness, and dis- 

 tribution of sea ice will be essential for 

 navigation in this area. 



MILITARY OCEANOGRAPHY 



The great expansion of oceanography dur- 

 ing the past ten years, amounting to a ten- 

 fold increase in the number of persons em- 

 ployed and the amount of money expended, 

 can be traced directly to recognition of the 

 importance of oceanographic information 

 for military problems. More than half of 

 the funds being expended for oceanographic 

 investigations at the present time come 

 from the Department of Defense. 



Oceanography has military applications 

 of four types : ( a ) in the design and speci- 

 fications of new equipment to take maxi- 

 mum advantage of the properties of the 

 oceans; (b) in testing new equipment to 

 meet requirements in operation at sea; 



(c) in the tactical use of equipment to 

 take maximum advantage of oceanic condi- 

 tions either as observed or forecast; and 



( d ) in strategic planning where knowledge 

 of average oceanic conditions can be used 

 in selecting the time and location of mili- 

 tary operations, the type of equipment to 

 be used, and the most effective disposition 

 of men and materiel. 



During World War II, oceanographic re- 

 search and information found effective ap- 

 plication in amphibious and undersea war- 

 fare. In amphibious warfare the success 

 of beach landings depends on accurate 

 knowledge of conditions in the surf and 

 shore zone. The most important of these 

 is the bottom topography immediately off- 

 shore, which may change rapidly depend- 

 ing upon changes in wave height and direc- 

 tion. If landing craft become stranded 

 before they reach the beach, the landing 

 troops may be subjected to a withering 

 fire in wading ashore and may be unable to 

 cross an intervening deeper zone. Just such 

 a situation existed at Tarawa, and the 

 losses incurred in that operation stimulated 

 the effort to find methods of determining 

 bottom depths in shallow water. Second 

 in importance to the bottom topography are 



