ADVANCEMENT OF MARINE SCIENCES 27 



i.his flaunting of our freedom of the seas brought our Nation into the 

 war on the side of the Allies. 



The enemy submarines were few in number, small, could submerge 

 only a short distance below the surface, and were required to surface 

 frequenth' to recharge batteries. Yet they confronted our Navy 

 with a menace that demanded action. 



The Navy did two things. It moved troops and supphes overseas 

 by convoy, and it called in scientists. The scientists invented the 

 hydrophone which could detect the sound of a nearby submarine 

 moving underwater. "When located, om- Navy surface craft could — 

 and did — dispose of them %\dth depth bombs. 



Hydrophones, the first underwater detection device, were crude 

 but they met the requirements of that era because submarines, too, 

 were crude. Thej^ were slow, nois}^, and, as previously stated, op- 

 erated near the surface. The enemy undersea menace subsided. 



Germany introduced better submarines in World War II and entered 

 that conflict with 47 in active service. She increased her undersea 

 tonnage as war progressed, and in 1942 sank more than 1,000 ships 

 between the United States and Em-ope. In that year also she added 

 244 new submarines, her peak construction year. Submarines were 

 diesel powered and operated no lower than 400 feet below the surface. 



Our Navy again called on science. Scientists and technologists 

 developed sonar. Sonar detects submerged objects by sending out 

 sound pulses and noting the echo. The use of sonar in combination 

 with depth charges, torpedoes and air power increased the enemy 

 submarine Josses and decreased the losses of allied ships. By 1944 

 the Germans were sacrificing one submarine for every alhed vessel 

 sunk, while 2 years earlier her submarines averaged 13 sinkings to 

 every loss, and in the year before that the ratio was 16 to 1. 



A fact that may have significance to world commerce, navigation 

 and security is that at no time during World War II did Germany have 

 as many submarines as Soviet Russia has today. 



Russia not only has more than three times as many submarines as 

 the United States; it has more than all the nations of the free world 

 combined. 



Most, if not all, of Russia's active submarines have been constructed 

 since the war. They are modern, s\vift, submerge to greater depths 

 and are far more quiet than those of World War II vintage. 



Russia's older submarines have been scrapped or turned over to 

 her satellites or to other nations which she seeks to woo into her orbit. 

 Among her beneficiaries have been Egypt, Indonesia and Communist 

 China. Part of this bounty also consists of early post-World War II 

 craft which have been replaced by advanced Soviet submarines. 



In brief, Russia today numerically is the world's No. 1 undersea 

 power. 



Vice Admiral John S. Thach, Commander of the Antisubmarine 

 Defense Force, U.S. Pacific Fleet, in an article titled "The Silent Paths. 

 of Destruction" published in a recent issue of Navy magazine, stated: 



The Soviets have over 100 submarines in commission in 

 the Pacific. In addition to these, the Chinese Communists 

 have the 4th largest submarine force in the world. As a 

 matter of fact, the great majority of these submarines are new 

 construction and their number has multiplied several-fold 

 within the past 6 years. 



