1. But we will want that fathometer badly as we approach Cape Horn. 2. The fathometer , or depth sounder, was developed commercially during the 1920s. 3. At one point her fathometer read only 30 centimeters of water under the keel. 4. A paper chart moves through the fathometer and is calibrated to record the depth. 5. The first practical fathometer was invented by Herbert Grove Dorsey and patented in 1928. 6. The Dorsey Fathometer instrument was used to get a precise measurement of water depth. 7. There were different models of the fathometer made initially by the Submarine Signal Company. 8. The indicator of the Dorsey Fathometer was a neon tube on a rotating disc. 9. Fathometers measure the depth of the waters.10. Eventually, CRTs were married with a fathometer for commercial fishing and the fishfinder was born. 
Mobile