Many boats produce turbulence around the transducer making it impossible to get a reliable bottom sounding at speed. While correct placement of the transducer is paramount (follow manufacturer’s inctructions to the letter) This simple tip will guarantee perfect soundings at all speeds.
Take a thin piece of plastic from an ice cream container or similar and cut out a vee the same size as your transducer. Use a good quality glue to stick it to the hull as shown.
This ensures a smooth flow of water past the transducer and eliminates turbulence.