Depth readings - Lowrance 330C

[brucehawsker]

My Lowrance 330C goes crazy above about 18 knots - gives a load of black lines on the fishfinder screen and no longer gives a meaningful depth - number flashes). Sometimes I have to switch off and switch on again even after slowing right down - it fails to re-acquire the bottom properly even at slow speed after a fast run.

Is this ' normal '?

Thanks

Bruce

[marknj]

Could well be down to position / installation of transducer. Have a look at other threads on this subject and if this sheds no light on it post a pic of your tdcr.
Cheers,
Mark

[swginn]

Bruce, as you know I've got the Lowrance 320 which is essentially the same unit as yours except without the colour screen. The transducers are identical though. Mine gives depth readings and perfect sonar picture all the way up to WOT. Lowrance sounders are well known for their great high speed readings so it must be down to the install. It sounds like you are getting some turbulence or maybe the sounder clears the water when you are planing through the bump stuff.

Heres a pic of how I've got mine mounted if it helps.

[brucehawsker]

It is certainly turbulence related. Here is a piccy of my installation. What do you think?

[brucehawsker]

Also, whenver I get it onto the trailer it is in a semi up position as though the water flow has pushed it upwards

[swginn]

Bruce, it is in a semi up position as a sort of collision protection system, it pops up if it hits anything, but can also pop up after a big jump at 30-40kts. You can remedee this by tightening up the nut & bolt either side of the rubber washers. The position of yours does look to be slightly higher up the transom than mine which might just be the cause.

Also you could try increasing the ping speed from the default 50% to 100% on the sonar. If you do this you may get a second bottom echo cluttering the screen which can be eliminated by decreasing the sensitivity slightly.

HTH!!

Steve

[simmons0]

Mine doesnt work over about 10 knots if it makes you feel any better Bruce

[brucehawsker]

Looking at the manual, it seems as though swginn's is placed in between two of the 'strakes', whereas mine is placed quite close to a 'strake'. The manual - see attachments - implies it should be mounted between these strakes. Is that my problem? Simmons0, where is yours mounted?

[Richard B]

Bruce - I would have thought that your depth transducer is quite simply just too close to the speed paddle wheel. Try taking the paddle wheel off temporarily and see if it improves?

[simmons0]

Exactly the same place as yours bruce. Under the outermost "strake"