Sediment has come up, and would explain part of observation when moving between sandbanks.
It does not come into play when in a tidal marina and tied up, not moving and still see indications go below 2 mtrs, and not touching.
I do understand how the system works, and transducer is 'straight down' that doesn't explain the irratic indications, unless powerlevel is such it would be impossible to measure correctly when so close to the ground. Any suggestions to different settings (dealer calibration)?
S/V Tutti ( Nantucket 33 by Alan Guerny )