Simrad B75M Medium CHIRP Thru-Hull Transducer 9-Pin

The Simrad B75M is a bronze thru-hull transducer built for boaters who want real medium-band CHIRP performance out of their sonar. Instead of pinging at a single fixed frequency the way older transducers did, the B75M sweeps a continuous band from 80 to 130 kHz. That swept signal is what CHIRP is all about, and it's why the returns look so much cleaner. You get better target separation, so two fish stacked close together show as two marks instead of one blob, and you get clearer bottom detail and structure at depth. For anglers chasing suspended fish or reading bait balls, that difference is the whole reason to move up to a transducer like this.

The B75M is a medium-frequency unit, which is the band you want when you're fishing deeper water or want more reach out of your sonar. It reads down to about 274 meters, roughly 900 feet, so it covers offshore depths that a higher-frequency transducer can't reach. The tradeoff between medium and high CHIRP comes down to what you fish. Medium CHIRP like the B75M trades a little fine detail in the shallows for more depth penetration and a wider search area, which makes it the smart pick for deeper offshore work and mixed fishing where range matters.

Physically this is a thru-hull design with a bronze housing, meant to install through a fiberglass or wood hull for the cleanest possible acoustic path. Mounting the transducer element in direct contact with the water, rather than shooting through the hull, gives you the strongest signal and the best performance at speed and in deep water. The tilted-element design is matched to hull deadrise so the beam fires straight down even though the housing sits at the hull's angle, which keeps your depth readings honest and your bottom lock solid. It handles up to 600 watts of power, plenty to drive the medium CHIRP band hard.

The beam works across roughly a 24 to 16 degree cone as it sweeps the band, giving you a useful search footprint under the boat. A wider cone covers more water and helps you find fish and structure, while the CHIRP processing keeps that coverage sharp instead of muddy. Built into the transducer is a fast-response water temperature sensor, so your display shows surface temperature without a separate sender. On the water, temperature breaks are one of the best clues to where fish are holding, and having that reading built into the transducer is one less thing to install and wire.

Connection is through the 9-pin xSonic connector, which plugs into compatible Simrad multifunction displays and sonar modules with a CHIRP-capable sonar port. That standardized connector keeps the install clean and makes it straightforward to match the transducer to the right display in your helm. If you're building a new sonar setup or upgrading an older single-frequency transducer, the B75M is the kind of component that lifts the performance of your whole system, because the transducer is where the sonar picture actually begins.

Getting a thru-hull transducer installed correctly matters. The hole has to be in the right spot for clean water flow, the housing has to be bedded and sealed properly, and the tilt has to suit your hull's deadrise so the beam fires true. It's worth doing carefully, and it's worth doing once. If you're not certain the B75M is the right match for your hull and your display, reach out before you order and we'll help you confirm it fits your boat and your electronics.

Think of the B75M as the foundation your sonar is built on. No matter how good your display and sonar processor are, they can only show what the transducer hears, so a quality thru-hull like this is where real performance starts. Match it to a capable CHIRP source and you'll see the difference in every screen, from a cleaner bottom line to better-defined fish arches to the confidence of a solid depth reading in deep water.