[TG] Rv100 shows deep depth falsely

[Tom - Raymarine - Moderator]

In the meantime then, can you describe the sounder image (in traditional/200kHz, let's not worry about 3D for now as it is much more complex)?

Have you tried Manual Range, setting the range to something a bit deeper than the expected depth?

How sure are you that this is a speed-related problem, working at higher speeds, and not for example related to a change in bottom conditions that perhaps coincides with you leaving a no-wash zone or similar? If you're sure it's speed, not location that's the factor that makes it work, there are three things that spring to my mind:
- poor flow of water or aeration across the transducer face when the boat is displacement/ploughing but not when planing
- a noise signal related to speed, e.g. hull section resonating with a harmonic of engine revs (this really happens, and just like a rattle in your car - or at least my car - is engine-rev-range specific)
- low supply voltage to the display, starving the sounder ping reservoir and preventing proper sounder power output, which is resolved when you get some surface charge in the batteries.

Tom