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CHRIS_aka_GWH
13-09-2002, 12:14 PM
afternoon all,
I have a new Lowrance X91 sounder in my new rig. Terrific sounding at trolling speed really happy.

Up on the plane I lose my bottom line. I still get a digital readout which appears to be accurate. I've played with the sensitivity etc but no difference. The book says the possible cause could be either cavitation or electrical interference.
I've dropped the probe deeper & played with the angle but still no change.

My Question...
Is this normal for the X91 or similar Lowrance sounders? Could other owners give me some feedback.

I could not tell you at what speed my Stacer 475 hits the plane but it travels at about 30-35 mph according to the gauge at 4000 rpm.
Aside from the motor there are no electronics near the probe - the battery is stored on the other side & it was all professionally fitted.

Any help or advice would be greatly appreciated,

chris

bassfanatic5
14-09-2002, 03:04 AM
G'day Chris,
I put an x71 in my new boat and i am having the same problem,i have tried every thing i can think of to fix the problem but haven't yet. I also have one of the new eagle trifinder2's in the boat and it works fine both sounders i have installed the same way and i only run 1 at a time.
The x71 looses bottom trace at 27mph and the tri finder holds it at 41mph.
If you do find something out let me know as i to would like to sort out this little glitch.
Cheers Damien

rwells9999
14-09-2002, 09:26 AM
Hi Chris,
I'm on my 5th sounder now and when I have purchased a new sounder the displays from each of them has been terrible. On the third or fourth trip the sounder responds better. I'm not sure if it has some coating on the case of the transducer that causes cavitation. I have a Humminbird Paramount Wide, and when I took it out for the first trip the display was almost black, on subsequent trips it just got better. I can do 52kmh and get good botton reso. Dont forget that the angle you have the hull working at and the angle of the transducer is a major factor. My advice is that if your transducer is just below the hull (1/2") and the same angle, be patient, I think that it will improve, dont ask me why this happens.

Robin

adrian
14-09-2002, 04:26 PM
hi guys

had the same problem when the boat is loaded on an overnighter camping have found that the angle of the transducer changes so the reading blanks out great at troll but useless at speed so try chaangeing the angle downn a bit more . this will mean doing it on the water

hope it helps

Anzac

Volvo
17-09-2002, 06:05 AM
Have had the same problem in past years and found that by moving the transducer to flatter water or stick it internally(through the hull)(ie stick it to the hull so it reads through it) it has illiminated your problem.
From the sounds of thing all are suffering from from airated water or however ya wish to describe it.
i have an elcheapo eagle back of the boat where it definitely works through clean water and works a charm at all speeds so cant see how your x91 or other wouldnt do likewise.
Just a matter of playin around till ya get the right spot its happy to work through.

CHRIS_aka_GWH
19-09-2002, 07:22 AM
thanks for the replies - seems I'm not alone. I've emailed lowrance & are waiting for a response, which I will post.
I've also repositioned the probe deeper & away from the nearest chine (?? is that the correct name for the lengthwise ridges on the bottom of a tinnie). Yet to test the new position. If that fails i'll alter the angle as per anzac's advice.
It's not electric interference from the motor as when I bring the revs up at idle it does not affect the readout.
Frustrating !!!
chris

CHRIS_aka_GWH
20-09-2002, 02:31 PM
for those interested & affected LOWRANCE REPLIED..

"Thank you for your inquiry. The unit should maintain a bottom track at all
times. The digital readout of the depth will begin to flash if the unit
loses track of the bottom. If the digital readout does not flash then you
may need to readjust sensitivity settings for a proper display. If however
you lose a bottom track and the digital depth also begins to flash, this
means your transducer may not be properly installed.
Ensure the transducer is placed on an area of the hull which does not leave
the water when on plane. The transducer must remain in a clear flow of water
at all times to maintain bottom lock. Do not place behind hull chines, water
inlets, or next to other sensors which may disturb the clear flow of water
over the face of the transducer. Ensure the transducer is oriented properly
for the correct angle of attack into the water. It should be level with the
bottom when in operation. However a slightly downward aft position can
improve performance at higher speeds.

Thank you for choosing Lowrance. "

I put in the inquiry late pm 12/09 & got response 17/09, not too bad considering weekend & the size of their market etc. - the response is informative - i'm surprised it doesn't appear in the trouble shooting guide of the owners manual.

At least i now know you should not lose the bottom trace at speed, & the relationship between the digital readout & bottom trace.

As i posted, i've moved the probe further away from its nearest chine & dropped it deeper. If that doesn't worked I'll then drop it's tail so it's shooting slightly forward.

Could the extra flotation of the ModPod on the nomad be part of the problem?

Either way it goes I'll post a result.

cheers,
chris

Fitzy
23-09-2002, 07:14 PM
We probably get 10 phone calls a day about exactly the same problem. Its all caused from getting air under the transducer. With planing hulls, the very nature of thier design IS to get air under the hull to gain lift & less drag. As described by others, you need to position your transducer in a position where it is going to get the cleanest water, this means not behind strakes (that's the name Chris) and as close as possible to the keel (centre) without getting too close to the motor. There's no set of rules that apply to a particular sounder on a particular hull configuaration. Everyone sets their boat up differently & has the weight/trim etc differntly.
Trial & error is the best bet, try to silastic the transducer in place & test it when dry. If that isn't right simply tear it off & try another spot. Once you've got the best spot, then screw/rivet/bolt it in place.
If you have a glass or plastic boat, you can get a shoot thru transducer, but be 100% certain that there's not one single air buble in the gel coat/glass/plastic underneath it, or you up that certain creek without a bent stick.

Cheers,

Fitzy..

CHRIS_aka_GWH
24-09-2002, 10:20 AM
ta fitzy,
the silastics a good idea if this new position doesn't work, will save creating a swiss cheese transom.
It's driving me nuts, I know you're not a Lowrance man but what I'm picking with this sounder at troll is amazing - I just need it at speed as well. A big part of how I chase the bigger stuff is to fish the bait rather than the location so I need to see what I'm passing over when motoring.
I'll be dunking it again tomorrow if the wind dies flinging some rubbers around, here's hoping.
thanks for the suggestion
cheers,
chris

Fitzy
24-09-2002, 05:02 PM
Hi Chris,
I don't currently run a Lowrance but they make good sounders, don't get me wrong. I just enjoy the 320 verticals & ease of use that the Zercom/Legend gives me.
I wish the x71 & 91 had hyperscroll like the 51 does. Don't know why it isn't an option as faster scroll speed can help separate fish packed in tight. Anyways....

Good luck mate & let us know how you get on.

fitzy..

CHRIS_aka_GWH
03-10-2002, 02:15 PM
angling the probe "aft" fixed it. That is having the rear end of the probe lower than its front end. Doesn't look like a parrallel shot at the bottom but works accurately.
Thanks for the contributions,
chris

bassmansrc
05-10-2002, 08:37 AM
One other thing that might help here is a narrower angle transducer. In the fresh water my finder works fine at all speeds. In the salt it's not so good loosing bottom at any speed over 20kms in water deeper than 10 meters.

From what I have gathered it's to do with my transducer being a wide beam or 20 degrees. I was told if I moved to a narrow beam transducer 8 to 12 degrees. I would keep bottom a lot better in the salt. The reason is the salt suspended in the water makes it harder for the signal to reach the bottom. Not sure if this has anything to do with your experiences though

Steve

ahoj
18-01-2006, 06:56 PM
Almost every tackle shop has adjustable transducer bracket around 11$ #screw to Transon and adjust for best effect...

Ahoj