what is this fishfinder showing me ?

Sun Dec 09, 2012 4:38 am

I'm having trouble understanding what the fish finder tells me about the bottom ie rock / sand / mud / weed . The manual isn't very helpful . Could anyone please give me some simple guidelines using these pics as a reference ?
Cheers .
IMG_8088_1_1.JPG

IMG_8089_2_1.JPG

IMG_8096_3_1.JPG
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Re: what is this fishfinder showing me ?

Sun Dec 09, 2012 10:01 am

blowin wrote:I'm having trouble understanding what the fish finder tells me about the bottom ie rock / sand / mud / weed . The manual isn't very helpful . Could anyone please give me some simple guidelines using these pics as a reference ?
Cheers .
IMG_8088_1_1.JPG

IMG_8089_2_1.JPG

IMG_8096_3_1.JPG

looks like a load of footprints in the snow :shock:

Re: what is this fishfinder showing me ?

Sun Dec 09, 2012 11:20 am

I take it that you are drifting. In the first picture I would normally be zoomed x 2. That said the bottom line looks narrow and all white - Therefore soft bottom. You have a show at 20' this could be anything, weed, fish, bubbles...who knows! I would not get too excited about that small show. More than likely just "noise".
Second and third pictures are similar.....soft bottom. The second picture is showing "stuff" that could be anything....fish...weed..etc. you would build up knowledge if you caught fish when that sort of show was going on. It really is not a great show for 40 feet.

Basically, narrow return = softer bottom
Wider return coloured = harder bottom

There will be an attempt to answer any questions :D

Re: what is this fishfinder showing me ?

Sun Dec 09, 2012 7:07 pm

hi jimc sorry to hijack the post but but novice here aswell so rockey areas show up red and less denser areas such as mud show orange or something accordingly down to sandy bottom white? sorry again for hijacking post have a garmin unit to go in and no real idea how it works only 2 wires to battrey and hope it dont cheers

Re: what is this fishfinder showing me ?

Sun Dec 09, 2012 7:19 pm

dont pop __ technolagey

Re: what is this fishfinder showing me ?

Sun Dec 09, 2012 8:09 pm

How to use a Fish Finder

http://youtube.com/watch?v=jcJE0fEsicI
Help me interpret my fishfinder images: http://www.stripersonline.com/t/813400/ ... der-images
Fishfinder pictures:
http://www.thehulltruth.com/marine-elec ... tures.html
How to turn your fish finder into a fish catching machine: http://www.amazon.com/Finders-finder-ca ... B006WO3F0U
Hope this helps!

Re: what is this fishfinder showing me ?

Sun Dec 09, 2012 10:07 pm

jacko1 wrote:hi jimc sorry to hijack the post but but novice here aswell so rockey areas show up red and less denser areas such as mud show orange or something accordingly down to sandy bottom white? sorry again for hijacking post have a garmin unit to go in and no real idea how it works only 2 wires to battrey and hope it dont cheers


Depends on your make/model/scheme. The stronger the colour the better the echo. The width of the line depends on the hardness of the bottom. Thin line = softer bottom. Heavy line = hard bottom.
While drifting you will see the difference easily. So no, different areas are not different colours per se.
You will see transition between rock and sand easily. The rocky bottom will be more colourful, heavy line and will appear "lumpy". Garmin have a "grey line" on B/w sounders and "white line" on colour units (the older ones. The modern HD units are different) this gives the best indicator of hardness. Make sure it is turned on.
Most sounders work perfectly well out of the box, on auto. If necessary reset to default and then start experimenting.

Re: what is this fishfinder showing me ?

Sun Dec 09, 2012 10:43 pm

hi again jim i went well above my means i bought a gps4208 second hand without realising that i needed sounder box transducer and the rest of whistles ive since bought a gsd 22 again second hand from states but still need transducer looking at other sites and reports the minimum i should go with is an airmar b60 as i think the deadrise of my colvic is 23deg these really vary in price depending where you look the closest i can find at right price is US unfortunitally have you any veiws as im just reading reports no clue to be honnest all help greatlly appreciated cheers

Re: what is this fishfinder showing me ?

Sun Dec 09, 2012 11:43 pm

jacko1 wrote:hi again jim i went well above my means i bought a gps4208 second hand without realising that i needed sounder box transducer and the rest of whistles ive since bought a gsd 22 again second hand from states but still need transducer looking at other sites and reports the minimum i should go with is an airmar b60 as i think the deadrise of my colvic is 23deg these really vary in price depending where you look the closest i can find at right price is US unfortunitally have you any veiws as im just reading reports no clue to be honnest all help greatlly appreciated cheers


It might be cheaper to use the GPS as a standalone and buy an Echo 300 or 500/550 sounder.
I was looking at a transducer in CH marine a while back. It had a superb fitting kit whereby it would shoot thru the hull and you could vary the angle could be a P79 or something. Might be worth ringing Leo up there. Looking at the specs of the gsd 22 you could fit a lesser spec tdcr and see how you get on.

Re: what is this fishfinder showing me ?

Mon Dec 10, 2012 2:13 am

JimC wrote:................. the bottom line looks narrow and all white - ...........

Many thanks to you all for those replies . I think I am getting there !
JimC , I wonder whether my problem is that I am trying to interpret the wrong line . Are you referring to the layer/line right at the top of the seabed image , that very thin one ? I've been focusing on the much thicker band lower down . From top down there is :
Very thin white
Red
Thick white
Green & blue

So might that mean sand which is on top of a harder layer of gravel which in turn is on top of something even more solid ? ( forgetting the green and blue layer for now ) .
Thanks for bearing with me .
ATB

Re: what is this fishfinder showing me ?

Mon Dec 10, 2012 10:36 am

blowin wrote:
JimC wrote:................. the bottom line looks narrow and all white - ...........

Many thanks to you all for those replies . I think I am getting there !
JimC , I wonder whether my problem is that I am trying to interpret the wrong line . Are you referring to the layer/line right at the top of the seabed image , that very thin one ? I've been focusing on the much thicker band lower down . From top down there is :
Very thin white
Red
Thick white
Green & blue

So might that mean sand which is on top of a harder layer of gravel which in turn is on top of something even more solid ? ( forgetting the green and blue layer for now ) .
Thanks for bearing with me .
ATB


No. The thick white band is the one. The thin White & thin red are just showing the bottom.

To give an example with my older sounder, it might make things more clear:
This is drifting over some broken ground Notice the thicker line where the return is better on the patch of rock. the "show" over the rock were cod. To the left of the screen the line is thin - sand in this case (because I know the area).
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Re: what is this fishfinder showing me ?

Tue Dec 11, 2012 1:05 am

Cheers , it is much less confusing now I know what I am supposed to be looking at .
To summarise : Disregard the very thin red and/or white lines sitting on the top, in effect they tell you nothing .
The thickness of the band immediately below those tells you what surface your bait will be sitting on ( unless the cod take it on the way down ! ) . The colour of this band is irrelevant , it is its relative thickness which matters .
So if you were over new ground and got a band of continuous thickness you wouldn't know whether you were constantly over mud or rock . You would only know that once you had passed over something different and could see how it affected the thickness of the band . The contours would give you a pretty good idea of what you were over , too ( as would getting snagged all the time or , more optimistically , what species you were catching ) .
To begin with you could simply make a point of noting what the band looked like while you were over whatever the map said should be below .
If my summary is correct then that's it sorted , many thanks again .

Re: what is this fishfinder showing me ?

Tue Dec 11, 2012 10:16 am

Cheers , it is much less confusing now I know what I am supposed to be looking at .
To summarise : Disregard the very thin red and/or white lines sitting on the top, in effect they tell you nothing .


Yes for the purposes of starting off... yes. That red line tells you where the bottom begins

The thickness of the band immediately below those tells you what surface your bait will be sitting on ( unless the cod take it on the way down ! ) . The colour of this band is irrelevant , it is its relative thickness which matters .


Colour here will give an indication of return...something biological or metallic will show up different to the main bottom. Thickness = hardness

So if you were over new ground and got a band of continuous thickness you wouldn't know whether you were constantly over mud or rock . You would only know that once you had passed over something different and could see how it affected the thickness of the band . The contours would give you a pretty good idea of what you were over , too ( as would getting snagged all the time or , more optimistically , what species you were catching ) .
To begin with you could simply make a point of noting what the band looked like while you were over whatever the map said should be below .
If my summary is correct then that's it sorted , many thanks again .


You have the gist now. I would always reckon going to a place where you know the bottom structure is a great idea. Get a feel for the picture shown. When you are drifting, the contours will show up rock and you will be in no doubt. Unless you are drifting very slowly or stopped. Then the line will be straight and the thickness will help.

Re: what is this fishfinder showing me ?

Mon Jan 28, 2013 12:17 am

Put your sounder on a deeper scale until you see the second echo under the first bottom echo this will give you the info you need. If you are over mud you will get a very faint second echo, if sand a more distinct thicker (not too thick) echo with no red running through the second echo(just yellow), if you are over gravel you get a wider top echo and also a wider second echo with flecks of red through it(not too much red!). If you are over rock or flat hard ground you will get a not so level top echo with a thick line also more red in it and your second echo will also be thicker with plenty of red in it. This all of course is how it is presented in perfect conditions with little roll, calm seas, a good quality sounder(commercial fishermen do not fork out anything up to 10,000 for a specific sounder for nothing)!Do not expect a cheap model to give you the same results! As for sounding the bottom do not steam along at 10knots and expect to get perfect bottom descrimination. The best speeds for bottom interpretation are around the 2 to 4knots range. A low frequency sounder (good models) wil show up fish with swim bladders when they are schooling. A high frequency sounder is better for mackerel, spurdog and fish that have no swim bladders. A big shoal of mackerel on a low frequency sounder will manifest in little more than a few scratches, whilst on the high frequency model they will show up as a big blob on your screen. When you are on fine bottom and approaching the rough you will see the side lobes come up on the screen this is very handy for staying on the edge of the ground when bottom fishing for mixed species. I am only familiar with this because of many years trawling and other forms of commercial fishing.

Re: what is this fishfinder showing me ?

Tue Jan 29, 2013 3:18 am

Many thanks for taking the trouble --- now I am really looking forward to seeing what I can get out of it :D