Overview

The Garmin B75 is a bronze, low-profile thru-hull CHIRP transducer family with a 600 W rating, depth sensing, and fast-response water-temperature sensing. It is offered in Mid-CHIRP (80 to 130 kHz) or High CHIRP (130 to 210 kHz) to match the water you run and the type of targets you want to separate.

Mid-CHIRP versions cover 80 to 130 kHz with a 24° to 16° beamwidth and are rated to a maximum depth of 274 m (900 ft). High CHIRP versions cover 130 to 210 kHz with a 15° to 9° beamwidth and are rated to a maximum depth of 214 m (700 ft). Installation is a true thru-hull that uses a 70 mm (2-13/16") hole, with a 95 mm (3.75") usable shaft length.

The internal tilt element is fixed at 0°, 12°, or 20° so the sonar beam points straight down when the unit is mounted close to flush. Match the tilt to the hull deadrise at the install location: 0° for 0° to 7°, 12° for 6° to 15°, and 20° for 16° to 24°. The bronze housing is intended for fiberglass or wood hulls and is commonly used on stepped, planing, or displacement hull forms.

Key features

• 600 W single-band CHIRP transducer with depth and fast-response water-temperature sensing
• Mid-CHIRP option: 80 to 130 kHz with 24° to 16° beamwidth
• High CHIRP option: 130 to 210 kHz with 15° to 9° beamwidth
• Fixed internal tilt options (0°, 12°, 20°) to match hull deadrise without adding a fairing block
• Thru-hull mounting with 70 mm (2-13/16") hole size and 95 mm (3.75") usable shaft length
• Bronze housing for fiberglass or wood hulls, with a low-profile shape that sits close to flush when installed correctly

Variants

This product is offered in multiple configurations to match both hull deadrise and sonar band.

The differences across the range are the fixed tilt angle (0°, 12°, or 20°) and the CHIRP frequency band (Mid-CHIRP or High CHIRP).

• 010-11636-20: Tilt 0° and CHIRP Frequency Mid-CHIRP. A 0° tilt matches flatter mounting areas (0° to 7° deadrise) while keeping the beam pointed down.
• 010-11636-21: Tilt 12° and CHIRP Frequency Mid-CHIRP. A 12° tilt aligns with moderate deadrise sections (6° to 15°) so the transducer can sit close to flush.
• 010-11636-22: Tilt 20° and CHIRP Frequency Mid-CHIRP. A 20° tilt matches higher deadrise areas (16° to 24°) where a straight 0° element would aim the beam off to the side.
• 010-11634-21: Tilt 12° and CHIRP Frequency High CHIRP. High CHIRP uses a narrower beam, which helps when you want tighter target separation in shallower water.
• 010-11634-22: Tilt 20° and CHIRP Frequency High CHIRP. This combines the higher-deadrise tilt range (16° to 24°) with the High CHIRP band for detailed returns in shallower water.

Installation and setup

Because this is a thru-hull install, plan on drilling a 70 mm (2-13/16") hole and having clear access inside the hull for the nut and cable routing. Pick a location that stays in clean water at speed and is clear of turbulence sources like strakes, steps, and intakes. A close-to-flush install helps keep drag down and protects the transducer from impact.

Sonar and system integration

Verify that your sonar source supports the band you are selecting (Mid-CHIRP vs High CHIRP) and that the connector and port type match your system before you commit to cable routing. Once connected, you will get depth plus water-temperature data from the built-in sensor.

Use cases on board

Mid-CHIRP is a solid fit for boats that split time between shallow and mid-depth water and still want meaningful bottom detail. High CHIRP is a better match when you spend more time in shallower water and care about separating targets near structure.

This transducer family makes sense for fiberglass and wood-hull boats where you want a low-profile thru-hull installation and you can choose a fixed tilt that matches the deadrise at the mounting spot.