B&G HS2000 - Manual (Page 81)

HS 2000 User Manual
Part 6 -Diagnostic Data
HB-0846-03
6-8
6.2.2 Boat Moving
Symptom: Display shows:
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- -
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when boat is moving; this is most often an indication of difficult
sounding conditions, but can also indicate a badly positioned
transducer.
Possible causes:
(a) Difficult sounding conditions and/or Depth Sounder
unable to track rapidly changing bottom. If entering
shallow water, the boat should slow down and proceed
with caution.
(b) Aeration in the water. Most often caused by the wake
of another vessel and can persist in the water for a long
period after the passing of the vessel. In some instances
the Depth Sounder will indicate the depth of the aeration
layer caused by a large vessel.
(c) Poorly sited transducer. Determine which conditions
are causing the problem; this is best achieved by
completing some maneuvering trials in an area which
has: a relatively uniform depth, a solid bottom and is
clear of the wake from other boats.
First, determine the maximum speed at which reliable soundings
can be made when traveling in a straight line. Then repeat the
tests when turning to port and starboard. If better results can be
obtained when turning it is possible that there is something in front
of the transducer causing aeration. This may be a rubbing strake
or other hull fitting, such as a water outlet; in which case the
transducer or the hull fitting should be re-sited.
If there seems to be little difference whether turning or not, the
position of the transducer should be reviewed. The transducer
may be coming out of the water at high speed or in rough water. It
is impossible to give specific instructions on where to re-site the
transducer since it is dependent upon the design of boat; generally
better results will be obtained nearer the centre line of the boat. If
there is only a problem when heeled, fitting two transducers with a
changeover switch should be considered.