Fishfinder issue?

[scugpg]

Hi all - I have an LMS-522c and I've noticed when I'm crusing around I can't seem to mark any fish going faster than 3-5mph and over that the screen goes blue (hard to explain). Could this be interference from the gas motor's electrical system, or does it sound like the transducer is picking up air bubbles or something? I currently just use a suction cup on the back of the boat and I try to position the TD just under the boat at the flat angle. Do you guys have any issues marking fish or with interference on your electronics?

[Roy]

Electrical interference is less common than turbulence interference. Make sure that the transducer is 18"+ from the center line of your gas motor. Ensure also that the bottom of the ducer is level with the water line and 1/4" or so into the water. You probably won't be marking fish in less than 15 or so FOW but you should never lose bottom. Can you give us a pic of the transducer position as it is now? front and side view?

[Greencoachdog]

Probably turbulence interference. A suction cup mount is about the worst way to mount a transducer, you should check into one of these.

 

http://www.cabelas.com/cabelas/en/template...&id=0000844

 

Roy is right about not marking fish in less than 15 FOW if you just have a single or dual beam transducer... but! if you have a triple or quadruple beam transducer your cone will be much larger in shallow water than with single or dual beams.

[limeyangler]

try also to angle the transducer slightly forward as opposed to dead level, its helped me...(i also have a lowrance) i can now do over 10 mph and get clear readings whereas when it was level anything over 3 or 4 mph and the screen was toast

[OhioFisherman]

Transducer positioning, angle as the boat is moving at speed, and mounting method can all cause problems.

[scugpg]

Thanks for the replies guys. Sounds like the suction cup might be the problem. I've attached a pic of where I typlcally have it sititng on the boat. I think it's far enough away from the motor.

 

Currently have it connected to my 24v batteries on the one with the (-) going to the trolling motor. Also have a ferrite power filter on the power line going to the lowrance.

[scugpg]

Here's another pic

[OhioFisherman]

Haven`t used a suction cup mount in a lot of years, I like the transducer with one on lower in the water, bubbles no clear stream of water under the transducer will cause problems. Even rivets on the bottom of the boat can cause problems in the water stream if the transducer is not low enough. Get it as far down as it will stick.

[Roy]

You're too deep. Go to the manual and check out page 15 and 16.

Online, you can find it here.

 

http://www.lowrance.com/upload/Lowrance/Do...-181_120406.pdf

[DRIFTER_016]

The problem with the suction cup is that it is not solid and moves around due to the water pressure on the transducer. The transducer is permanently mounted on my boat and I read bottom at full speed (35+ MPH).

Reading fish at speeds over 5 or so MPH is difficult due to the size of the target and the speed at which you pass over that target. The faster you go the more compressed the image gets. At trolling speed you may pass over a large school of bait that presents as a big ball. That same ball of bait at speed will show as a vertical line. By speeding up the chart rate you can fix this compression issue, but it can only go so far.

[scugpg]

You're too deep. Go to the manual and check out page 15 and 16.

Online, you can find it here.

 

http://www.lowrance.com/upload/Lowrance/Do...-181_120406.pdf

 

I thought it was supposed to be 1/4'' below the boat? Sounds like I have a project to mount this thing permanently. I like the bracket GCD mentioned...maybe I'll make one of those rather than drilling through the transom. Good to know about it not marking fish over 5mph though....never loses bottom but I'd like to get the best image possible and start using this thing....really only used it as a depthfinder this year so want to get my $'s worth on this unit.

 

cheers,

 

scugog