Humminbird Side Imaging Forums

Side Imaging Forums => 798c SI => Topic started by: Daniele_Mari on July 19, 2010, 04:20:57 AM

Title: Thermocline
Post by: Daniele_Mari on July 19, 2010, 04:20:57 AM

Good morning.

I noticed that my 798 ci is not able to show me the thermocline as other fishfinders do.

Such as an 898 of a friend of me , in the same area.

Could you tell me , please , if I have forgotten to set up something ?

Regards

Daniele

Title: Re: Thermocline
Post by: Wayne P. on July 19, 2010, 08:00:36 AM

Mine shows the thermocline great and even on DI and SI.
DI and 2D sensitivity set to 10

Title: Re: Thermocline
Post by: sonar2000 on July 19, 2010, 08:37:27 AM

Daniele, can you post a picture of the screen and where you think the thermocline might be.
As Wayne said it could be settings also. 
Chuck

Title: Re: Thermocline
Post by: Daniele_Mari on July 19, 2010, 09:32:52 AM

I meant the line with the double tempetatures indicated up and down.

There are al lot of examples here, but I haven't ever seen it on my screen ...

For example Wayne , in you snapshot I noticed the thermocline, but it is not shown as I expected.

Sonar, I do not have a snapshot for this.

I will do some new snapshot the next time.

For example:

[img width=800 height=480 alt=]http://forums.sideimagingsoft.com/MGalleryItem.php?id=207[/img]

Thanks for your replies

Title: Re: Thermocline
Post by: Wayne P. on July 19, 2010, 10:19:12 AM

I don't have a fully developed thermocline screen shot with my 798 yet (hasn't been hot enough long enough). Here is one from last summer that was taken with my Matrix 97. The sensitivity was set to 10

Title: Re: Thermocline
Post by: Wayne P. on July 19, 2010, 10:20:56 AM

This is the same thermocline with a lower sensitivity setting to clear up some of the clutter:

Title: Re: Thermocline
Post by: Daniele_Mari on July 19, 2010, 10:27:43 AM

Thanks Wayne.

but

is it really the Thermocline

please have a look.

(http://forums.sideimagingsoft.com/index.php?action=dlattach;topic=1458.0;attach=2908;image)


Temp on the left is 82.8 and on the DI is 93.

Has anybody noticed it ?

Thanks again .

Daniele

Title: Re: Thermocline
Post by: countryboycansurvive on July 19, 2010, 11:57:33 AM

The actual surface temp of the water is 82.8 as shown on the left.  What you're seeing in the di view is the limits of the temp scale on which the temp graph is being plotted.  In other words there is a graph of the temp plotted in the di view and the graph is being shown with a top limit of 93 and a lower limit of 73.  As you move from cooler to warmer water you will see the graph start to trend up.  The unit only measures the surface temp of the water, so to find the thermocline you have to look for a steady return on the screen which indicates the change in water density which forms the thermocline.

Title: Re: Thermocline
Post by: sonar2000 on July 19, 2010, 01:44:39 PM

Daniele, thanks for the picture. I dont think that is a thermocline. It looks more like a large pile of old trees or brush.  A recording of the run would be nice for looking at the SI view in comparison.
Wayne and CountryBoy  have given a good answer also........ hope that helps. 
Chuck

Title: Re: Thermocline
Post by: Wayne P. on July 19, 2010, 01:51:13 PM

countryboy is correct, the temperature sensor on your transducer cannot measure where it is not located. That readout/graph you have is a history of transducer temp changes. Here is a copy of a screen shot from another site showing the temp graph. You will notice the uneven line from right to left that indictes a temp change has occurred several times. My unit does not have that graph, but if the range is adjustable to have a narrower temp difference, the changes would be a lot easier to notice:

Title: Re: Thermocline
Post by: Daniele_Mari on July 19, 2010, 03:12:05 PM

I got you guys.

Thanks ...

Really cool .

Title: Re: Thermocline
Post by: Daniele_Mari on July 26, 2010, 03:14:36 AM

Guys, do you usually use switchfire on to detect Thermocline ?

Title: Re: Thermocline
Post by: Wayne P. on July 26, 2010, 06:18:37 AM

I keep mine on Switchfire Clear all the time. I haven't tried the other setting to see what the thermocline looks like. I'll check that out this week.

Title: Re: Thermocline
Post by: Daniele_Mari on July 26, 2010, 07:11:00 AM

I' m on the Switch Fire Clear Too.

Title: Re: Thermocline
Post by: Daniele_Mari on August 03, 2010, 05:15:29 AM

Wayne, do you have any interesting shots with the Switch Fire on ?

Title: Re: Thermocline
Post by: Wayne P. on August 04, 2010, 02:16:24 PM

Daniele, that image was done last year before Switchfire was added. I added it and removed it after experiencing screwed up shallow water readings. That was with my Matrix 97.
This is the thermocline with the 798 in the Switchfire Clear setting done a couple of weeks ago. The thermocline is not very dense yet and I only did the screen shot at the thermocline level while checking for contours at that level.
The DI sensitivity was set at 12.

Title: Re: Thermocline
Post by: LocDown on April 11, 2011, 08:47:11 PM

[attachment=1]

I think this is one from a pond to go to quite a bit. This was late march 2011.
I believe it's a thermocline. .

Title: Re: Thermocline
Post by: sonar2000 on April 12, 2011, 09:01:27 AM

At 8.5 feet I am not too sure of a thermocline..This could be the propwash from your or another boat near you......Or surface clutter.  This can probably be filtered out with settings...
Chuckj