Humminbird Side Imaging Forums

Side Imaging Forums => 898c SI => Topic started by: ferney69 on February 27, 2011, 02:36:56 AM

Title: 898c si loosing bottom reading
Post by: ferney69 on February 27, 2011, 02:36:56 AM
I'm having problem with my 898c si loosing the bottom reading when on plane. For example my 898c si unit reads fine while idling around, when i make a run, it reads fine for about 10 seconds then  looses the bottom reading and goes back 1.ft and freezes to that range till I slow down again. I have the XAP 9 20 thru hull transducer with the Y cable connected to my unit. It was working fine before, no troubles? The last three trips out, it does this every time. The unit is fairly new, bought it last Aug. It has worked great till now. Any help would be greatly appreciated.
Title: Re: 898c si loosing bottom reading
Post by: sonar2000 on February 27, 2011, 08:28:52 AM
Who installed the transducer?  do you have pictures?
Possibly the installation left some bubbles or you are getting bubbles due to the location..(cavitation)
Chuck
Title: Re: 898c si loosing bottom reading
Post by: ferney69 on February 27, 2011, 03:22:11 PM
[attachment=1] First, thanks for your response Chuck, I bought my Stratos at Cabelas so I assume the installation was done there. I wasn't loosing bottom signal with my other Hummnbird unit. Here's the pic of my transducer.[attachment=2][attachment=2]
Title: Re: 898c si loosing bottom reading
Post by: sonar2000 on February 27, 2011, 06:55:00 PM
Thanks for the pictures.  That does not look bad at all. 
Can you remove the y cable and try running direct to the unit with the thru the hull. 
Could be a loose or vibrating cable. 
Hopefully the cable layout will let you do this.
Chuck
Title: Re: 898c si loosing bottom reading
Post by: ferney69 on February 27, 2011, 08:17:33 PM
I'll be taking the boat out on Tuesday and will try running directly to the unit without the Y cable. I will let you know how it works. Thanks Chuck
Title: Re: 898c si loosing bottom reading
Post by: Humminbird_Greg on February 28, 2011, 04:40:21 PM
Just a few observations here:
That does not look like raw fiberglass right around the transducer.  The best installation jobs will have the transducer epoxied directly to the raw fiberglass and not whatever type of paint it is they coat the inside of the hull with as it is usually porous and reduces the sonar signal strength.

Can you tell if the stuff they used to bond the transducer to the hull is hard or soft?  The ‘goop’ they used is clear and while I have seen clear epoxy I’m worried that it may instead be some kind of silicone, which would be a bad thing as it can absorb additional sonar signal strength.

Title: Re: 898c si loosing bottom reading
Post by: ferney69 on March 01, 2011, 12:52:51 AM
Greg the stuff around the transducer is hard and the the color of the goop is white. I cleaned around the transducer while trouble shooting the problem the other day. Ill post another pic you might be able to see it better. Thanks for your help Greg.

         
Title: Re: 898c si loosing bottom reading
Post by: ferney69 on March 01, 2011, 05:59:31 PM
Chuck I took the boat out today and connected the dual beam directly to my unit without the Y cable like you said and took two snapshots. First pic,  I'm piking up speed and the second running about 40mph. Still seamed to have same results however my readings would pop back up while running but were very weak returns but my bottom depth would read fine? Can it be my transducer going bad?
Title: Re: 898c si loosing bottom reading
Post by: sonar2000 on March 01, 2011, 07:38:51 PM
On the second pic I see that the GPS looks like it has lost contact.
Try checking the cable where they plug into the head and make sure they are tight and using the connector housing.

HMMMMM I hate to even go here but the unit might be having a problem.

Check all connections first,

Then give HB cust support a call and get a problem ticket opened.

Let us know about the connections at the unit head. (back side)  especially the power connection. and of course at your main supply. check for a loose fitting fuse...

Chuck

Title: Re: 898c si loosing bottom reading
Post by: ferney69 on March 01, 2011, 10:36:23 PM
Chuck I only had the dual beam and power cord connected to the unit when I took the two snapshots. After testing it without the Y cable, I tested with the Y cable and all the connections. I took these snapshots. The first pic I was in about 20ft of water and it reads 1.6 and weak returns and the second reads the same as I was slowing down. Thanks for your input Chuck.

Title: Re: 898c si loosing bottom reading
Post by: RGecy on March 02, 2011, 01:36:37 AM
ferney69,

Where is the transducer located in the hull?  Are there any steps in front of it or rails that would cause any air bubbles?

Also Greg mentioned that the transducer didnt look like it was epoxied to the bare fiberglass.  If there is any air between the layers of fiberglass or significantly thick, it could cause a week signal like this.

Robert
Title: Re: 898c si loosing bottom reading
Post by: ferney69 on March 02, 2011, 05:39:57 PM
The transducer is located in the hull and there is no steps or rails that would cause air bubbles. It is epoxied to the fiberglass but don't know if it is to the bare fiberglass. I had it checked by a boat shop and they seem to think the problem is with my transducer since I'm getting very week returns, so I'm having it replaced Friday, they said after removing the old one they would sand it to the bare fiberglass to ensure a good install. Hopefully it will fix my problem, I will keep you posted on the outcome, thanks for your help Robert.
Title: Re: 898c si loosing bottom reading
Post by: Humminbird_Greg on March 03, 2011, 04:10:58 PM
ferney69,
Make sure that they test the mounting location before mixing any epoxy!  I know that it is a PITA to do so but the results are worth it.  I know of a guy in North Alabama who had an inside-the-hull transducer “professionally installed” than replaced twice by the same shop for a “bad transducer”.  Turns out that the mounting location was bad which they would have known if they tested it the first time they installed it…
With an XAP9-20 transducer this will be more of a challenge due to the sloped hull but it can be done.  Look at the picture below.  This can be done for testing purposes as long as you have something on top of the transducer so that it does not move around.

My money would be on a deteriorating bond between the transducer and boat hull.  The location may be fine since you said that it worked before but not now, so that leaves the transducer and the transducer-to-epoxy-to-hull bond.  With the transducer being installed on top of the paint it casts doubts in my mind about this bond.  If this bond is starting to fail you would start to see a loss in signal strength (sensitivity to you) in the 2D sonar whether moving fast, slow or sitting still.  You may not notice it on the last two but do on the first (moving fast).  If it is the epoxy bond starting to fail you could test for this by filling your bilge with enough water to cover half way up the transducer and see if it works better.  You may have to disconnect your bilge pump to try this though.

Tell the folks that are replacing your transducer that you want your old transducer (whole and not with the cable cut) when they are done.  Than test it by holding it over in the water and see if it gives a good reading or not.  Be sure and knock off the old epoxy before doing so.

Title: Re: 898c si loosing bottom reading
Post by: ferney69 on March 03, 2011, 06:23:32 PM
  I'll make sure to talk with them when I drop it off in the morning. Keeping the old transducer is a good Idea I'll be sure to mention that as well. As soon as I can get it on the water I'll take some snapshots and hopefully this fixes my problem. Thanks for the info Greg
Title: Re: 898c si loosing bottom reading
Post by: ferney69 on March 04, 2011, 11:35:32 PM
After picking up my boat late today, got it on the water just before dark and made couple of small runs. I didn't get a chance to mess with any settings or anything, but wow, nice to see how deep I was running. Took couple of snapshots. I can't wait to get back out.  ;D
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