[TG] Replaced DSM300 with CP370 to restore numeric depth reading

[Tom - Raymarine - Moderator]

Good day Rip,

Can you post some screenshots or clear, high-res, full-screen photos of the CP370's sounder image on both 50kHz and 200kHz, both in all-Auto and in the following Gain setup:

Gain = 60
Colour Gain = 15
TVG = 0
Range = manual, set to 1.5x to 2x the real current water depth

This will give us valuable information about the reason for the poor performance. The manual gain setup is in order to provide a benchmark comparison against other sounders, so the specific values are important.

One comment at this stage though: very often the cause of this sort of thing occurs because of problems with in-hull transducer installations. Wet-boxes can leak or fluid evaporate, not all hull materials are suitable (I understand it worked with the DSM, but perhaps it 'only just' worked, and the CP370 has a different TVG curve which means that it may receive a different signal level in a particular shallow water depth than the DSM did, and perhaps its different software is rejecting the weak, shallow bottom return.) I'm not saying by the way that the CP370 is inferior, quite the opposite is true, which is why I'm focussing on an external cause for the poor performance rather than the CP itself.

Regards,
Tom