Fishfinder: to be or not to be

[pupu]

recently bought a combo garmin unit for my dinghy and been trying to learn using it , problem is most of the people i ask tell me the plotter is good for charts but fishfinder dont rely on it cause it misleads you. what you guys think ?

[ganni]

i have both a fish finder and a gps, the gps is not so accurate in the depth measurements. however a fish finder is accurate in the depth it will read. however don't rely on the fish finder for searching fish, just use it to have a clear idea of the bottom

[pupu]

i was hoping for a different answer but it was just the same as the other fisherman. Malta is known to have very clear waters so why do you think sonar technology which echo's back to the boat will give a wrong reading. it's like saying all this reaserch for nothing. just asking , but it bothers me seeing youtube video's which for a reason cant be applicable to malta

[busumark]

i think what ganni was trying to say is that not all the echoes that are on the screen are fish, they could be seaweed,jellyfish,interference and a lot of other things. But the fishfinder will give exact depth reading and the composite of the bottom.

[anglers]

How can you guess of what the bottom is made from the fishfinder?  I have a garmin 400 fishfinder

[busumark]

if its a colour fishfinder you can tell what the bottom is by the colours if its not coloured you should have diferent shades of black and the some fishfinders have a whiteline. but its better if you read the instructions they explain better than me

[ramio]

The gray scale as I think it is known is the indication of the type of bottom being echoed. The harder the bottom, the stronger the echo back to the sounder.
The range of the depth depends on the unit and transduced used. last year I installed a new set up on my boat which included the combination of the Cobra Marine MC 600 GPS with the MF 2500 black box. This together with the B260 1kw dual frequency trancducer has already given me a range of 650m. This coming season will try to trim it a bit more. The manufacturer states a max depth of 735m. Quite happy with the setup. What amazes me about this systems is the frequency of the pulses is so high that it gives a very clear reading even at planing speeds.

[pupu]

on my garmin 420s i have whiteline setting but it says low med or high , which one should i use to know it its sand or rock? and if the whiteline is thick it means which