Hellcats by Peter Sasgen Read Free Book Online Page A

Sound Laboratory (USNRSL) at Point Loma. UCDWR had been established in early 1941 to carry out research and development for the Navy under a contract let by the National Defense Research Committee (NDRC). Harnwell was a respected physicist and educator from Cambridge and Princeton universities. He had also taught physics at the California Institute of Technology and, before the war, had headed the physics department at the University of Pennsylvania. Steeped in advanced electronics and engineering concepts, he wanted to demonstrate for Lockwood some of the new prosubmarine gear, as it was called, undergoing development at UCDWR’s labs. Because prosubmarine gear was high on Lockwood’s list of priorities the sub force needed to counter Japanese antisubmarine measures, he eagerly accepted Harnwell’s invitation to see what progress had been made in that area.
    Earlier in the war Harnwell’s efforts had been focused primarily on the problems associated with what was then called “subsurface warfare,” a discipline that encompassed not just antisubmarine weaponry but also mine detection. As the tempo of Pacific submarine operations increased, the need arose for devices to enhance the inherent stealth of U.S. submarines and to improve their survivability in combat. Harnwell and his staff of scientists had been working on such devices and were eager to demonstrate them for Lockwood’s benefit. Not only did they have a rapt audience but also one who understood how difficult such specialized work was and how much time it had taken to develop the prototypes of the gear on display.
    Harnwell demonstrated just about everything in UCDWR’s inventory. It included a device that could detect an incoming torpedo’s range and bearing; a sonar decoy similar to that of the German U-boat “pillenwerfer,” a cartridge filled with calcium hydride that when mixed with seawater produced huge quantities of hydrogen gas that bubbled like an out-of-control Alka-Seltzer tablet to confuse enemy sonar; ultrasensitive long-range passive—listening only—sonar for the detection of enemy ships; a bathythermograph, a device that recorded the varying temperature layers in seawater, which, because it had a masking effect on sonar, made submarine detection more difficult than it already was; depth-charge direction and range indicators; and, to help reduce a submarine’s self-generated noise signature, a propeller cavitation warning device. Amazed at what he saw, Lockwood lamented that the sub force still lacked these “Alice in Wonderland” gadgets, which he believed would have vastly increased sinkings of Japanese ships and no doubt have saved hundreds of American lives. All he could do was put the devices on his wish list; he knew that despite the best efforts of Harnwell’s scientists, it would take many more months of testing and refinement before the advanced prosubmarine gear reached the submarine fleet—if it ever did.
    After conducting a tour of the lab, Harnwell sprang a surprise on Lockwood. Harnwell and his assistant, Dr. Malcolm Henderson, who, like Harnwell, was a brilliant, dedicated physicist, took their guest for a cruise off Point Loma in San Diego Harbor to demonstrate an experimental sonar device capable of detecting underwater mines and which was slated for installation in navy minesweepers. Henderson had led the group of scientists responsible for creating the device and was eager to demonstrate its abilities. Despite being a prototype with a spaghettilike breadboard electrical layout, the thing performed well enough to give Lockwood a peek into the future, even though, he admitted later, he failed to grasp its significance.
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    The device Harnwell had demonstrated for Lockwood was called FAM-PAS, or Frequency and Mechanically Plotted Area Scan. Its name would soon be changed to Frequency Modulated Sonar and later shortened to FM sonar, then just FMS. The device