Overview

The Garmin B150M is a 300 W CHIRP-ready thru-hull transducer that operates in the medium band (95-155 kHz) and connects through an 8-pin plug. It reads depth and water temperature, with a published maximum depth of 183 m (600 ft) in typical conditions. The body installs almost flush to the hull, and the internal tilt corrects the sonar beam angle without adding a fairing block.

Installation requires a 51 mm (2 in) hull hole and enough access inside the boat to tighten and seal the stem. The bronze thru-hull housing is intended for fiberglass or wood hulls, where corrosion resistance and a secure mechanical fit matter over long seasons in the water.

Key features

• 300 W, medium-band CHIRP operation (95-155 kHz) for depth sounding
• Depth and water-temperature sensing in one thru-hull unit
• Low-profile thru-hull form that sits almost flush to the hull, so a fairing block is not required
• Fixed-tilt element options (0°, 12°, 20°) to match hull deadrise angles up to 24°
• 51 mm (2 in) thru-hull hole size with a 66.5 mm (2.62 in) usable shaft length
• Medium-band beamwidth listed at 26° x 17°
• 39 ft cable with an 8-pin connector for compatible Garmin sonar ports

Variants

This transducer is offered in three fixed-tilt configurations.

The tilt angle is built into the housing to match your hull deadrise so the beam points straight down when the transducer is installed nearly flush to the hull.

• 010-11927-22: Tilt 20°. Covers hull deadrise angles from 16° to 24° for deeper-V running surfaces.
• 010-11927-21: Tilt 12°. Covers hull deadrise angles from 8° to 15° for moderate-V hull sections.
• 010-11927-20: Tilt 0°. Covers hull deadrise angles from 0° to 7° for flatter hull areas.

Installation and setup

Plan the mounting location where the transducer face will stay in clean, aeration-free water when underway. Typical placement is forward of steps and away from strakes, intakes, and other fittings that can feed turbulence across the face.

Because this is a thru-hull installation, sealing and torque matter as much as the electronics. After the first few trips, it is worth rechecking for any sign of seepage and confirming the cable is supported so vibration does not work on the connector or strain relief.

Compatibility and fit

The B150M is a single-band, medium-frequency CHIRP transducer (95-155 kHz). Your sounder needs to support CHIRP and be rated to run a 300 W transducer.

Connector fit is equally important. This version uses an 8-pin transducer plug, so confirm your Garmin unit or connected sonar module uses the matching 8-pin transducer port before ordering.

Use cases on board

This is a practical match for boats that spend time fishing or cruising in shallow to mid-depth water and want a medium-band CHIRP return with a beam shape that helps separate targets around structure. The fixed-tilt options are especially helpful when you want a clean install on a V-hull without building up the outside of the hull with a fairing block.

Maintenance and care

Keep the transducer face free of heavy marine growth so readings stay consistent. During routine haul-outs or dives, check the housing for corrosion, confirm the inside nut remains secure, and inspect the cable for chafe anywhere it passes through bulkheads or rigging runs.