Topic: 1158C fishfinder readings

[Mark129]

Hi,

I've had my 1158c installed for a month or more now, all is well but it does not read the bottom very well if the water is deep or the boat is moving very fast.

At my local seamount, water is 500' and rises to 300', the picture is VERY grainy at slow speeds and useless on plane.

In 60 to 80 feet of water at slow speeds the picture is great, but at 20 to 28 mph the picture will have lots of gaps.

I'm using a shoot through the hull transducer.  Is there anything I can do?  Would the transom mount transducer help?

Thanks,
Mark

[Roddy]

Mark; Seen this happening on other units.

Check out Sensitivity Page #137, Lower Rande page #138,
Chart Speed Page #139, Noise Filter page# 170,Max Depth page# 170,Transducer Select page# 172.

Shot Thru hull xducer will lose a lot of sonar return.

I have this happen to me a number of times in deep water (150+ feet).

   Good Luck and Enjoy Roddy

[Humminbird_Greg]

Mark129,
Try setting the Beam select menu to the 83kHz setting and see if that improves the readings any.

Do you get gaps in the bottom reading when running at 20+mph in shallower water (like 20 feet deep)?
If so, than this could be a sign of a bad installation, a deteriorating installation or (shudder) a sign that the hull is delaminating.  Was the inside-the-hull transducer tested in its present location before it was epoxied in place?

[Mark129]

Thanks for the reply's guys.  In smooth, shallow (10 to 20 feet deep) water I can get a constant, not broken, line on my recorder with the boat on plane, 24 +/- mph.

I have the transducer mounted in the same spot my old Airmar was located.  I got great performance from my old unit, a Garmin 2010C with a separate black box GSD20 sender.  Well, the Garmin was very unreliable, but when it worked it read the bottom well.

When I go to Beam Select I can get a reading on the recorder using 200 or 83/200, but just 83 the screen is blank, no reading.

Thanks again for your help.

Mark

[Humminbird_Greg]

“When I go to Beam Select I can get a reading on the recorder using 200 or 83/200, but just 83 the screen is blank, no reading.”

Is this at any boat speed?

How did the transducer test before you epoxied it in place?

In smooth water, how deep can you go and get a reliable depth reading at the same speed?

[Mark129]

At 83 kHz I get no reading at all, no indication of the bottom.  As soon as I switch to 200 or 200/83 I get a good bottom reading.

The transducer works about as well epoxied in place as it did before I glued it down, maybe some better actually.  I ran the boat a few times before glueing with water in the bilge and the transducer anchored with a couple sand bags.  I had a good picture for most of what I do (60 to 150 feet of water) at slow speeds, I was hoping final installation would fix the gaps.

I've wondered about the no reading at 83 kHz.

[Humminbird_Greg]

Mark,
What is the model number of the transducer you are using?  This should be on the cable within a few feet of the connector end.

Any chance that you can test your unit on someone else’s boat that has a Humminbird unit to see if the 83kHz works?  Most any Humminbird model will work for this test.

[Mark129]

Greg,

I plugged the factory supplied transom mount transducer into my 1158C and got the same reading as I get from the shoot through the hull transducer (model number XP9 20T), that is I get a bottom reading on 200 kHz and 83/200, but nothing at all on just 83 kHz.

Then I took my 997C si and plugged it into the same connections I use for my 1158C.  Doing this I was able to get good readings on the fish finder from 83 kHz, 200 kHz an 83/200, and just sitting at the dock the picture changed slightly going from 83 to 200, like it's supposed to I imagine as the angle viewed changes.

So it seems like the 83 kHz part of my new 1158C is inop, what do you think?  would having the 83 kHz working improve my high speed and/or deep water performance?

Thank you again (and again!) for your help.

Mark

[Humminbird_Greg]

Mark,
Yes it does sound like the 83kHz is not working in your 1158c unit.  What version of software are you running?  Maybe updating the software will reset something in the unit allowing the 83kHz to work.  My guess is that getting the 83kHz to work will help with your deep water readings but not with the high speed readings.