LOSING BOTTOM ON SOUNDER

[Brokenrod]

I've got a Lowrance 337c gps/ sounder combo. The transponder is the dual frequency transponder that comes with most all Lowrance's resent units.
I have it transom mounted with the correct amount of clearence in relation to the hull. I lose the bottom at speeds not much faster than trolling . I've ajusted the height + - 3/4 of an inch with no real change. I'm considering the through hull mount. I have a 21" Trophy HT. Does any one have any suggestions or experience with this type of installation on a deep V hull. [?]

 

[Butt Ugly]

I would have a look at the transducer while you are under way and going fast enough to where you lose the bottom. If the transducer is in turbulance and bubbly water, then you will need to relocate it.

 

[eaglemaniac]

You might also want to check the transducer itself, as Lowrance transducers are infamous for the wire that enters the transducer as well as the plugin itself of popping out. Once they do there toast.[xx(] eman

 

[blueorca]

I had the same issue with my unit.
I installed a baffle plate above the unit to drive the water downward and to eliminate the rooster tail when at speed.
Cured both issues quite well and was cheap to install.
I will post a picture momentarily.

 

[saltybeaver]

I have the same unit and problem.

 

[blueorca]

Here's a link to the picture for you.
I used a piece of clear plexi-glass so you can still see the unit from above.

 

[Brokenrod]

Thanx Paul, Kev phoned me, gave me some pointers that should solve the proplem. At least a starting point. As for the rooster tail, I have a large swim grid that sound fix that, but if it doesn't...

 

[marula]

I have a second el cheapo sounder with the transducer epoxied to the bottom of the bilge, this way it reads clean at speed and does not add any more gear to the transom. As long as both sounders are not on the same frequency they will both work at the same time.

 

[fishwish]

I'm dealing with the same problem right now with my 335c, except I not only lose bottom at high speed, but it also won't read bottom deeper than 180 ft. I called Lowrance, described the problem, and they said the the transducer is probably hooped. I also noticed that when the boat was on the trailer, and the sounder was on, the ticking of the sonar was completely different than it had always been.

Long story short, I orderd a new transducer, and I'll pick it up tomorrow. Lowrance said that they would compensate if this wasn't the problem.

Oh, another thing that surprised me, when the Lowrance guy asked how long I have had the unit, I answered four years. He then went on to say that the transducers shouldn't really last that long in the first place[xx(]. That doesn't sound good.

FishWish