False transducer readings

I'm getting crazy false depth readings on my Lowrance 4 w/Chirp & DSI ( 3 yrs old)...flashing depth readings as well.Could it be improper install on transducer or just a bad transducer.. what is the best thru hull mounting for this transducer

The mounting on the 2015 or later TI puts the transducer in the water and its all set up for that transducer (I think). I have an older Lowrance model 4 something or other with maybe a similar transducer, never have any depth reading issue (the peak speed reading is however completely out of whack).

If you are shooting through the plastic hull, any air gap at all between the transducer and the inside hull will do what you are describing.. at least in my experience. I had a transducer mounted to the inside bottom of a dingy sailboat shoot through the hull. Used epoxy and worked fine until the glue delamitated and did about what you describe.

I saw a youtube video one time- might have been a Hobie video but I believe they made a little "pool" and used Goop to glue the transducer to the plastic inside the hull. If you dont have the 2015 TI hull or later (dont know about he AI), you might try and find that video.

Thank you..I have a 2012 Outback. My Lowrance Hook 4 comes with a small closed cell foam form thats set inside the hull, and the transducer fits snugly into it. I learned yesterday that it's necessary to put a little water in that form to eliminate air gaps between transducer and the hull ,apparently no goop necessary, although i believe some do that.

After putting a small amount of water in the form today, and securing the transducer in it , it worked very well today, so all it took was a little water to sit the transducer in. hopefully i'm good now.