6 days of sailing through lots of depths from 8 feet to well over 200 feet showed a tendency to read what I think were accurate depths with reasonably frequent periods of time that she read 3.5 feet. While there is only one transducer
the Bi-data and the C-80 would show values close but not identical unless it was 3.5 feet. I do wonder if perhaps 3.5 feet might be the minimum it would show and that weeds may have caused the issue but certainly far from certain.
I had lots of other strange things including an autopilot
that would not hold a heading and frequently would show "no data" then shut off and the gps
position on the C-80 showing us jumping all over the place when sitting tied to the dock
or moving in a straight line. Starting to think they are all related to a bad connection or part. I did have to replace the circuit board of the ST40 wind
instrument as it would lock the system up when connected and this was only solved
when I replaced it.