# Help with transducer mount on flat bottom aluminum boat



## pcsolutions1 (Jul 22, 2009)

Just got my Lowrance HDS 7 and installed it in time to run up for a test this evening.  It's a fantastic unit and the sonar worked very well at slow speed.  When I run at speed across the lake, it would lose the bottom and would not even show the depth.  I did not have the same problem with the Humminbird 798 with the transducer in the same spot.  Any ideas?  Boat is a 1654 tracker grizzly.  I have it mounted on the right side about 15 inches to the right of the motor and inbetween 2 of the bottom ribs.  I had it lined up with the bottom of the flat of the hull and not with the bottom of the ribs.  How do you guys do them and do you have this trouble?

Any help will be greatly appreciated.  

By the way, I'm sure this will be resolved, but the unit is fantastic.  The GPS is much easier to use and the maps much easier to read.


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## CardsFan (Jul 23, 2009)

That's got to be frustrating.   I would almost suggest trying a higher ping speed (and the obvious xducer alignment), but it should work straight out of the box if your HB unit was tracking bottom fine at high speed.

Since you mounted the xducer in the same spot as the old one, I would think that location would have been fine, but maybe someone who knows more can comment.   I assume you needed to mount a new xducer and you routed the cable in the same location as the HB?

I have an aluminum jet with a xducer bracket that allows two heigth positions.  In the summer when I'm running shallow rivers, I mount it high so I don't bust the xducer, but I can't get a good bottom lock on plane in deeper lakes.  In Winter when I fish lakes instead of rivers, I move the xducer down and then I get a good reading on plane.   Perhaps the xducer is just not low enough?

Email Linda Colt at Lowrance at Linda.colt@navico.com and she might be able to help you.


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## kscoggins (Jul 23, 2009)

I have similar problems, interested to hear opinions/experiences also.


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## 20ReevesCC (Jul 23, 2009)

My buddies 522 lowrance does the same thing but my hds-5 works great at all speeds. I would try to adjust the ping speed and the chart speed also it might be a sensitivity setting issue. I would call the manufacture to get the best advice.


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## pcsolutions1 (Jul 23, 2009)

*question*



20ReevesCC said:


> My buddies 522 lowrance does the same thing but my hds-5 works great at all speeds. I would try to adjust the ping speed and the chart speed also it might be a sensitivity setting issue. I would call the manufacture to get the best advice.



What types of boats are your buddies and yours?  I will try the faster ping speed for sure.  I called Lowrance and they were actually pretty quick to answer which should make some feel better after the issues they have had.  He told me to try to lower it and to move it to the cleanest looking area of the water off the back of the boat.  I agree, I thought it was working well so just put it in the same spot and especially with the smaller transducer it should be great.  I'm sure it's an adjustment of some kind.

Thanks,

Tom


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## Doyle (Jul 26, 2009)

Give up.  You'd be extremely lucky to get any transducer to work at high speeds on a light, flat-bottomed jon boat.  Transducers have to have pure water under them to work.  Any air bubbles will break the signal.   Flat bottomed jon boats generate too many air bubbles that trail under the transducer.


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## fishlipps1952 (Jul 26, 2009)

it'll work ....it's just a matter of getting it located properly without having to drill a lot of holes in the boat....someone, somewhere, makes a plate that you can mount on the back of the boat that gives you lateral adjustment....to get away from the rivets and ribs....you just need to get the DEPTH set right, first..

my boat is just a 16' jon....a little "beefed up", but still a jon....and mine reads running in the mid 30's.....


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## little rascal (Jul 27, 2009)

*Here's a couple pics*

of two different set-up's on two different style flat hulls.
First is "true flat hull"  1/8" thick, aluminum bracket with double sided 3M tape. The hull has no crimps on bottom like on production jons. They have longitudal ribs, which when dented create a tunnel instead of hook, like you get in regular jons with vertical or side ribs. A hook can and will cause more air bubbles. Those crimps are there for strength, due to thinner hulls and not for grip(keels) as most would think, move your ducer away from the crimps and avoid any hooks ahead of the ducer.
 My ducer will swivel up when I jump logs, stumps, shallow mud etc., and can be adjusted back in position later.
The second set of pics are on a crimped bottom flat jon(production hull). This is an Alum. L bracket epoxied to hull and ducer epoxied to bracket. Works well, but if you hit something shallow it may have to be re-poxied, and has once!


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