A80011 B265LM D/T Bronze CHIRP Transducer for CP470 (Low/Medium)

The Raymarine B265LM (Part # A80011) is a 1 kW dual-band CHIRP transducer that combines low and medium frequency ranges, offering exceptional versatility and a complete view of the underwater environment. Built to pair with high-end sonar modules like Raymarine’s CP470 and CP570, this bronze thru-hull transducer allows anglers and navigators to cover the entire water column – from the ocean depths to the mid-levels – using a single device. Employing advanced CHIRP technology, the B265LM greatly enhances target clarity and sonar sensitivity by transmitting over a sweep of frequencies in two bands (Low and Medium), rather than a single frequency ping.

In the low CHIRP range (42–65 kHz), the B265LM can penetrate to approximately 3,000 ft (around 900 m). This makes it excellent for deep-water exploration and fishing – you can track bottom contours in the open ocean, locate submarine canyons and drop-offs, and mark large targets lurking far below the surface. The low-frequency beam is relatively broad (up to ~25° at the lowest frequencies), which means it covers a large territory and helps you find interesting bottom features or concentrations of fish without needing an extremely tight grid search.

In the medium CHIRP range (85–135 kHz), the transducer focuses on mid-depth zones – roughly up to 1,000 ft (300 m) – with improved resolution. The medium-frequency beam is narrower than the low (about 16° at 85 kHz, narrowing to ~11° at 135 kHz) but still wider than a typical high-frequency CHIRP beam. This moderately wide coverage in the medium band is extremely useful for tracking moving schools of fish and scanning more water volume in the mid-range depths – for example, when fishing pelagic species like tuna or mahi-mahi that roam between the surface and deeper waters. At the same time, the Medium CHIRP provides sufficient detail to distinguish individual fish and structures, albeit not as fine as a High CHIRP would. In practical terms, the B265LM gives you a broader “radar” for the mid-water column compared to a Low/High transducer, while still retaining the ability to “punch down” deep with its low channel.

When used with a dual-channel CHIRP sounder (such as the Raymarine CP570), the two channels of the B265LM can operate in parallel, enabling simultaneous monitoring of deep and mid-depth ranges. The low CHIRP channel keeps an eye on the bottom and deep structures, while the medium CHIRP channel watches for activity closer to mid-depth. This is especially valuable during trolling or drift fishing, where bait and gamefish may be spread at different levels. The combined transducer eliminates the need for a second unit to cover the mid-range depths, saving you space and installation complexity.

As with the other models in this family, the B265LM comes with a fairing block to ensure proper installation on hulls with up to 20° deadrise. A correct installation with this fairing guarantees that the powerful transducer is oriented straight down even on V-hulls, which is critical for accurate sonar returns. The fairing also promotes laminar water flow across the face of the transducer and reduces aeration, improving the reliability of the echo readings at speed. With the B265LM, you can count on steady sonar tracking even at high boat speeds – similar to the B265LH – as both are engineered for professional-grade performance under demanding conditions.

The transducer provides both depth and temperature data, adding valuable environmental information to your fishing or navigation decisions (for instance, being able to note a thermocline or temperature break that might attract fish). Its robust bronze housing indicates that it’s built for longevity in the saltwater environment. (As a reminder, this thru-hull is intended for non-metal hulls; if you have an aluminum or steel hull, you should use appropriate isolation or a different transducer to avoid interference.)

Compatibility: The Raymarine B265LM connects directly to Raymarine CP470 and CP570 CHIRP sonar modules via its 11-pin plug (cable of ~33 ft is attached). It also works with the CP450C module. If you are running modern multifunction displays with CHIRP sonar built-in (such as the Axiom Pro series), this transducer can be integrated as well, using the same standard Raymarine CHIRP connector. In essence, it’s easy to add the B265LM to your existing system without adapters, which simplifies the upgrade process on board.

The Raymarine B265LM Low/Medium is the ideal pick for those seeking a do-it-all transducer for both offshore and coastal waters. Installed on an appropriate vessel (typically 33 ft and above, where a 1 kW sonar can fully shine), it gives you the advantage of simultaneously monitoring deep and mid-depth realms. Whether your goal is to target bottom fish dwelling at 2,000+ feet or to follow a fast-moving school of tuna at 300 feet, the B265LM has you covered. The comprehensive picture it paints beneath your boat means more opportunities to find fish and better understanding of the underwater terrain. The product comes with a 2-year warranty from Raymarine. Routine cleaning and the application of a compatible anti-fouling coat on the transducer face will ensure peak performance season after season.