C-Max CM2 User Manual page 16

CM2 Sidescan Sonar User Manual 4. Planning the Survey
In order to identify a target, or to provide extra assurance of coverage, it may also be necessary to follow the
along-current lines with a set of perpendicular, cross-current, lines.
Sometimes the major consideration in planning lines is not the direction of the current but the bathymetry. It
is easier to survey along lines of approximately constant depth rather than to be constantly heaving and
veering tow cable to keep the towfish at a suitable altitude.
Finally, the wind direction may be the controlling factor. Waves running across, rather than in the same
direction as, the survey line will cause a spiralling movement of the tow cable and oscillation of the towfish
track. This will have more of an effect on the image than the simple pitching motion if the ship is running into,
or directly away from, the waves.
Version 3.6 (2008)
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