A80015 B765LM D/T Bronze CHIRP Transducer for CP470 (Low/Medium)

The Raymarine B765LM Low/Medium CHIRP transducer (Part # A80015) is a bronze through-hull sensor that delivers advanced dual-band sonar performance for Raymarine’s CHIRP sounder systems like the CP470 and CP570. With a 600 W power rating and cutting-edge CHIRP technology, the B765LM offers the performance of larger 1 kW transducers in a more compact, efficient package – well-suited for mid-sized offshore fishing boats. Because it’s a CHIRP transducer, it transmits a continuous sweep of frequencies within each range (low and medium), rather than a single frequency pulse. This results in much better target clarity, improved fish separation, and reduced noise clutter compared to traditional sonars.

The B765LM operates across two CHIRP frequency bands: Low (40–75 kHz) and Medium (80–130 kHz). This gives anglers the flexibility to probe different depths with optimal detail. In low-frequency CHIRP mode, it can reach depths of roughly 1,200 ft (around 350–365 m), enabling the penetration of deep waters to reveal bottom structure and large targets in the depths (perfect for deep wreck scouting or bottom fishing offshore). The low CHIRP beam is relatively wide – up to ~32° – which means it covers a large area beneath the boat, helping to scan broad swaths of water for structure or bait schools. In medium-frequency CHIRP mode, the range extends to about 700 ft (200+ m), and the beam narrows to approximately 24°–16° (at its tightest), providing greater detail and target separation in the mid-depth range. The medium CHIRP is excellent for tracking gamefish in the mid water column and for getting a clearer picture of bottom features in intermediate depths where a high-frequency transducer might be too narrow. Together, the low and medium bands offer a versatile one-two punch – deep coverage plus detailed mid-range resolution – giving you a comprehensive view of the water column.

To ensure optimal performance, the B765LM comes with a high-performance fairing block included. This fairing block, installed on the exterior of the hull, streamlines water flow and allows the transducer to be mounted at the correct angle on vessels with hull deadrise up to 24°. By using the fairing, the transducer face can be aimed straight down even on V-hulls, which maximizes sonar return strength and accuracy. The fairing also helps maintain a strong bottom lock at high speeds. With this setup, you can expect stable depth readings even at cruising speeds of 30 knots or more, a critical feature for tournament anglers and serious cruisers who don’t want to slow down when scanning for fish or navigating.

The B765LM provides both depth and water temperature data. The built-in temperature sensor allows you to monitor sea temperature changes – extremely useful for finding temperature breaks and currents that often attract bait and gamefish. Constructed with a rugged bronze housing, the transducer is built to withstand continuous saltwater use, and its thru-hull installation ensures it stays submerged in the water flow for more reliable readings (no popping out in chop as can happen with transom mounts). (As with all bronze thru-hull transducers, it is intended for fiberglass or wooden hulls; it is not recommended for metal hulls unless properly isolated, due to potential signal interference.)

Compatibility: The Raymarine B765LM is equipped with an 11-pin plug that connects directly to Raymarine’s CHIRP sonar modules – namely the CP470 and CP570, as well as the earlier CP450C. Additionally, this transducer can interface with modern Raymarine multifunction displays that have CHIRP sonar capabilities built-in (such as the Axiom Pro RVX, Axiom 2 Pro RVM, the RVX-1000 module, etc.) using the same standard connector. This means you can plug the B765LM straight into a compatible system without needing any adapter cables. The transducer comes with a 33 ft (10 m) cable to accommodate installation on a wide range of boat sizes.

In summary, the Raymarine B765LM Low/Medium CHIRP transducer is an excellent choice for offshore anglers with boats in the ~30 ft class (and above) who want to dramatically enhance their sonar capabilities. It offers a wider coverage than high-frequency-only transducers while still achieving substantial depth penetration. By deploying this transducer, you gain a fuller picture below your vessel – from deep bottom structure to activity in mid-depth waters – giving you a significant edge in finding fish and understanding what lies beneath. It’s backed by Raymarine’s 2-year warranty for peace of mind. For best results, applying a transducer-safe anti-fouling coating on the bronze face will help prevent marine growth and maintain performance over time.