RAdio Detecting And Ranging / SOund Navigation And Ranging

A little WW-2 story from the newspapers of the day follows:

Fish Noises Confuse Sub Crews ON Look Out for Sounds of Foe   

Denizens of Deep Grunt, Purr, drum find Grind Their Teeth With Surprising Effect, Men at Earphones Of Undersea Craft Find; Navy Records Disturbing Blasts         

       WASHINGTON, Aug. 19 (AP). -- U. S. submarines turning corners at 10 fathoms or so have pulled up in surprise and wonderment at hearing such raucous sounds as "honk, honk! beep, beep!--g-r-rrrr!"

       The men with the earphones who listen to what gees on while their craft is slithering through the briny deep, often confuse these noises with the hum of enemy propellers, and signal for a quick stop, look, listen.

       But, as it turned out today, the eerie underwater traffic noises often are caused by fish.

Yes, sir. Fish.

       The fish and wildlife service of the Interior Department has reported to its chief, Secretary Ickes, that little fishes are as noisy as dishes, when rattled.

       "Fish," said the F. and W. service in a formal report, "actually grunt, purr, drum, grind their teeth and make a medley of other sounds that create strong underwater vibrations even when inaudible on the surface."


       The F. and W. service, aided and abetted by the Navy, has made a series of recordings of fish noises which are being drummed into the ears of submarine "listeners" so that they will know the difference between an ichthyological burp and a Japanese propeller.

       "The Navy experts," said the report to Mr. Ickes, "obtained their most surprising results with the toadfish, a common species of the Atlantic coast known for its ugliness and its bad temper. Although advised by fish and wildlife service biologists that the toadfish is an important sound-producer, the investigators were unprepared for the volume of its voice which they said compared in intensity with a steam-boat whistle."

      "Fishes capable," the report went on, "of making drumming, grating, or grunting noises are found both in fresh and salt water in all parts of the world. Whether fishes use their voices to attract, the opposite sex, as a feeding call, or to express general contentment like a cat's purr is not known."                                                                                                                          


This reference: (Wilmington, Delaware) Journal-Every Evening, August 19, 1943, p. 10, C1 

Nice to know we can detect small fishes and obviously, large undersea submarines. Now how about those “U.F.Othercraft ????

       This page is for the accumulation of cases that deal with Radar or Sonar so that we can see from them, what to expect in “returns”. Admittedly, the greatest number of cases will come from Radar inasmuch as it encompasses aerial UFOs as well as those on the surface.