The fathometer, or depth sounder, was developed commercially during the 1920s. Use of a continuously recording fathometer on "Atlantis" cruise No. There were different models of the fathometer made initially by the Submarine Signal Company. The indicator of the Dorsey Fathometer was a neon tube on a rotating disc. "Atule" had been equipped with the first upward-beamed fathometer for measuring ice thickness overhead. The "Fathometer" was so named by Dorsey because it measures fathoms. The first practical fathometer was invented by Herbert Grove Dorsey and patented in 1928. Eventually, CRTs were married with a fathometer for commercial fishing and the fishfinder was born. On 23 February, "Triton" detected a previously uncharted seamount with her fathometer. The ship's fathometer was not designed for such depths. The Dorsey Fathometer instrument was used to get a precise measurement of water depth. Then, during an overhaul, she received a fathometer, a Kleinschmidt distilling unit, and SJ radar. A paper chart moves through the fathometer and is calibrated to record the depth. His 'deep sea lead,' a pressure-activated fathometer was another minor, but enduring success. With Dorsey's Fathometer a ship could go at full speed and get the measurements.