I had a new fishfinder installed this spring. I noticed that when I'm going fast it shows 1200ft depth in 30ft. Also, it has vertical lines about every inch. My installer says it's not because of transducer in the wrong location, but programming. Now he's not returning my calls. Any ideas what the cause might be?
Hello r0ckteacher,
The cause will be either air under the transducer, or high background noise. Boats are noisy places at speed, some noisier than others, and if the sounder can't here the bottom echo amongst the noise then you get no bottom trace and the sounder goes into Bottom Search Mode and ranges right out. There's a lot of information about the causes and how to diagnose these problems
on this FAQ. Feel free to take screenshots and post them back here for us to have a look.
Regards,
Tom