Fishfinder and sea bottom nature

[Roberto]

I am looking for a colour fishfinder capable of givi g information about the nature of the sea bottom, usually through some colour scales related to sea bottom echo response.

Ideally, depths would be up to 20m so no particular need of something going to 200m; also, no interest in fishes so the ability to detect echoes at mid-depth would be irrelevant.
I have read a few instruction manuals but they all concentrate around fishing, what shoul I look for in terms of transponder frequencies, beam angle, power, chirp/not chirp, etc etc ?

Any models to suggest, preferably in the lower price bracket

Thanks r

 

[fisherman]

The small Koden is good, and will cost you about £500. Some Garmin kit is around £300, you very much get what you pay for. That one comes with the tranny, the Koden doesn't.

 

[Roberto]

The small Koden is good, and will cost you about £500. Some Garmin kit is around £300, you very much get what you pay for. That one comes with the tranny, the Koden doesn't.

Thank you fisherman, much appreciated
r

 

[Ric]

There is no sounder that I know of that will tell you directly the nature of the bottom by colour-coding. I don't think any manufacturer has yet made an algorithm that will detect and colour code (say) sand as yellow, or weed as green etc (probably somebody might do it soon). However, after you have used sounders for a while you can tell fairly accurately what you are dropping your anchor onto.

I have a "classic" Raymarine fish finder (which is actually intended to detect fish swim-bladders but also gives bottom reflections which change according to whether weed or sand or shingle). I also have a Raymarine dragonfly multi-spectrum which is excellent at picking out detailed structures on the bottom such as chains and wrecks, but less good at showing the bottom substrate. They are both useful in different ways.

 

[johnalison]

Tallow is what you need.

 

[Baddox]

Most echo sounders will give an idea of the bottom. The echoes from a hard bottom like rock will be stronger than from a soft muddy bottom. Sounders usually display the stronger echoes as thicker, darker lines to define the bottom.