Needing help to figure out why I loose my depth reading while on plane at speeds past 30 mph. I have two units on my boat, a Lowrance Elite 9 on the dash and a Humminbird 1198C SI mounted to the side. Neither will read depths unless at idle. Thinking it has to do with how transducers are mounted. Both are mounted on starboard side but there is space between them. I thought one might interfere with side scan image, but was at least hoping for good depth readings from at least one of the other. Should I remount one to the port side, or will prop wash be a problem?

A clear picture of how and where they are mounted would help. Usually loosing reading while on plane is from either being mounted too high or aerated water passing over the surface of the transducer.

Agree with tmd, it is all about transducer location. Send pictures.

Have trouble posting pictures. Can only text , if someone would post them for me.

Looking at the transducers I’m trying to visualize which one might be too high. Running a straight edge from hull to transducer they appear to be mounted at the right height, except the Humminbird 1198C might be angled slightly upward from the back end of the transducer. This is the unit I expected to get my depth readings from. So, maybe I should tilt it downward? Still can’t load pictures, so that’s not any help.

The Humminbird si ducers are difficult to get depth readings on plane. It can be done but most go with a shoot thru ducer with a y Cable or a 2d skimmer ducer. If you look at the transducer it has a line all the way around it to where the top half and bottom half come together. You want to try and line that line up with the bottom of you transom to where the bottom half of the transducer is bellow the hull

I’ll try that. Thanks