Description

The graphic recorder is the shipboard part of a side scan sonar system, which translated the pings from the towfish into data that humans can read. This Klein Model 595 sonar recorder is contained in an upright metal box in Klein Associates’ signature light blue with black accents. The top of the unit has a small digital display and a few basic command buttons to control the sonar frequencies. These are mounted on a door that provides access to the circuit boards that controlled and processed signals from the towfish, along with knobs that experienced operators could use to fine-tune the signal processing. The bottom of the unit contains a thermal printer, which printed data on a continuous roll of paper that spooled out the front of the unit.

The Klein Model 595 Digital Recorder was introduced at the end of the 1980s and marked a major shift in the function and utility of sonar technology. It was the first sonar model to process incoming signals from the towfish digitally, making automatic adjustments to amplify different signal lengths (time varied gain) and adjust for different bottom types. For a legible readout from previous generations of sonar, an experienced technician had to manually adjust incoming signals. Digital processing allowed professional archaeologists and other sonar amateurs to use equipment on their own, significantly expanding the reach of the technology.

The Model 595 sonar recorder was also capable of sending sonar pings on two different frequencies and print the results simultaneously, minimizing the need to compromise on image clarity or range or the need to cover the same patch of water twice. The thermal printer itself was also a leap forward, and much more user-friendly than the delicate rotating helixes and wet emulsions of earlier generations of recorders.

This Model 595 recorder was owned and used by Jim Whitaker, a Florida-based shipwreck hunter.