Luke Steele – Captain, REDS

Spent some time on the lake on April 21 working on sonar.  Wanted to pass along my observations so far.

First I would like to thank Munroe (props to Connie Beasley) for his enthusiastic support of this exercise – I could not have done it without him.  He’s not much in the way of conversation, but he’s a tireless trooper that never complains or asks if we’re done yet.

The purpose of this exercise was to start determining the best combination of settings and mode to detect a human-sized figure using Sonar.  The tool in this case was a Garmin 943xsv head unit driving a GT56UHD transducer.  Tests were conducted with Munroe in a semi-seated position in both 10 and 20 feet of water.

Both sidescan and ClearVu modes were tested, at 455 and 1070 kHz.  ClearVu at 1070 seems to be the clear winner:

At both 10 and 20 feet, the shape was clearly discernible and the dimensions were semi-correct – you can even see the line going to the surface buoy.  The negative is that the transducer must pass almost directly over the target – even a few feet right or left is enough to obscure the image.

Sidescan also produces some interesting images once you know what to look for.  This image, at 20 feet clearly shows the figure:

I have a lot more work to do in trying to refine the settings, but I think that this device holds a lot of promise for locating objects in the water.  The biggest question is how the density of Munroe compares to the real thing (sorry Munroe), but I’ll have to save that for another day when I have a patient diver.