This entry level B150M Tilt Thru-hull Transducer CHIRP solution provides good depth capability and target separation.
This 8-pin 300 W bronze thru-hull mount transducer has a depth of 1,500 ft; an operating frequency of 95-155 kHz; a beamwidth of 26/17 degrees; and a 8 to 15 degree deadrise.
Transducer kit comes with installation instructions. Follow the instructions carefully to avoid damaging your boat.