Depth finder always at 3ft? troubleshooting

[JWhit]

I just got the power connected to an old depth finder, very simple display with depth and alarm. It is connected to a puck transducer in the bilge, and always reads around 3 ft, give or take a very small amount. Any ideas which component may be causing the problems or if there is anything i can do to test? Don't have the model of the finder with me unfortunatly. Thanks for any advice!

 

[Silvertip]

Re: Depth finder always at 3ft? troubleshooting

You have what's called a "shoot through hull" installation of the transducer. The transducer will not work properly if there are any air bubbles between it and the water. transducers cannot shoot through air.

 

[JWhit]

Re: Depth finder always at 3ft? troubleshooting

It's an original installation, 1989 boat. is it likely that some of the sealant has deteriorated and that is causing an issue? I'll try to clean up the area around the transducer and look for any signs of trouble