A diagram of the old wiredrag system as developed by Nicholas Heck, Jean Hawley, and others in the U

A diagram of the old wiredrag system as developed by Nicholas Heck, Jean Hawley, and others in the U. S. Coast and Geodetic Survey. Prior to the development of sidescan sonar, this was the only method to find protrusions from the bottom that occurred between sounding lines. This diagram was published in the “Military Engineer”, 1924, p. 228.

Photo Category: Historical Ships - Sounding