Alexander Behm patented the first echo depth sounder in either 1907 or 1913 (??). He was trying to invent something to detect icebergs, spurred on by the Titanic tragedy. He never developed anything useful in detecting icebergs, but found echo sounding an excellent method for reading depth.
I think the trademark "Fathometer" was registered in 1914 based on development work by a Canadian engineer, R. A. Fessenden. It was a common aid to navigation long before WWII, and was used in the 1920's and 1930's as a charting tool as well.
It is effectively SONAR, just that a Fathometer device uses a low energy pulse directed directly downward. All the work on early echo location led directly to lateral SONAR for sub hunting.
|