Operation Manual
FarSounder, Inc.
F31552 (Rev. 3.8.0)
Page 58 of 69
floating in the middle of the water column. However, even obstacles laying on the seafloor can reflect well
beyond the bottom mapping limit. To illustrate this case, consider a rock on the seafloor as shown in figure
A.5. The rock creates a reflecting surface that is able to angle the reflected signals back to the sonar rather
than forward-scattering them away from the sonar. It may not be possible to tell the exact depth of that
obstacle, but it can be clearly detected as an in-water target.
Figure A.5. Reflecting off an in-water target beyond bottom mapping range
The ability to detect obstacles beyond a sonar's water depth limit is extremely important. Vessel operators
can detect the edge of rock ledges, shore lines, submerged coral reefs, and other navigation hazards. This
is helpful even in charted areas. For example, charts often mark an area as "reef" or "rocks" but don't give
the exact locations. Sometimes channel markers are missing or have moved from their nominal locations
on the chart. The sonar can help the vessel operator know exactly where their ship is located relative to
the edge of the channel.
Please visit the screen shots gallery at http://www.farsounder.com for examples of shallow water operation
at ranges well beyond our water depth capability.
