A80041 TM265 LM D/T Transom CHIRP Transducer

The Raymarine TM265LM CHIRP transom transducer (A80041) is among the most powerful fish-finding sonars you can mount on your boat’s stern. Combining two ranges – Low and Medium – this transducer gives you the advantage of covering an exceptionally wide swath of depth with optimal clarity. 1 kW of power and eight high-sensitivity ceramic elements mean the TM265LM can “punch” through the water column down to roughly 1000 m (depending on conditions), returning strong, clear echoes from the bottom and targets in the water.

The CHIRP technology employed by the TM265LM continuously varies the transmit frequency within each range (Low or Medium), and Raymarine’s specialized modules (like the CP470, CP570) receive and process the echoes from these signals. Why does this matter? Because instead of one single frequency ping, CHIRP sends out a “whole chord” of frequencies and listens for the tune coming back. This results in significantly higher resolution and contrast in the sonar image: individual fish in a school are more clearly separated, fish can be distinguished from structure or bottom, and the bottom itself is delineated with greater precision.

The TM265LM is a dual-spectrum transducer:

• In the low frequency band (Low, 42–65 kHz) it emits long-wavelength pulses that penetrate deep waters. The wide beam (up to ~25°) means you cover a large area beneath the boat – ideal for searching for pelagic fish or mapping structure when deep-water trolling. While resolution is lower than the medium band, at 300–500 m depth the Low CHIRP still gives you remarkably good imagery, where conventional sonars would long have lost definition.
• In the medium frequency band (Medium, 85–135 kHz), the transducer uses shorter wavelength pulses that provide finer detail. The beam here is narrower (~16° at 85 kHz down to ~11° at 135 kHz), which concentrates the energy – perfect for mid-depth ranges, say up to ~200–300 m, where you want maximum resolution. In practice, Medium CHIRP is often used to pick apart individual fish near the bottom or to clearly image structures (e.g., when bottom fishing on reefs at 100 m, this band can show you crevices, rocks, and the fish around them with exceptional clarity).

It’s worth noting that the TM265LM is a D/T, i.e., Depth/Temperature transducer, which means that in addition to sonar echoes, it provides depth (calculated from the return) and water temperature data. The temperature sensor is valuable for fishing – fish often relate to thermoclines (the boundary between warm and cold water layers), and with this transducer you can see when you pass through such a layer by a sudden change in temperature reading.

Mounting the TM265LM is transom-style. Despite its high power, the transducer is designed in a compact package for external stern mounting – avoiding the need to drill a hole in your hull (as you would with thru-hull transducers). Special consideration has been given for high-speed protection: the bracket allows a bit of kick-up if it strikes debris, and keeps the transducer angled correctly in the water flow. With proper installation, you can expect reliable readings even at faster cruising speeds (of course, maximum detail is usually obtained at slow speed or idle, as with any fishfinder).

Compatibility: The TM265LM (A80041) uses an 11-pin connector which is standard for Raymarine’s CP470 and CP570 CHIRP sonar modules, as well as integrated units like the Axiom Pro RVX and new Axiom 2 Pro RVM (which have a direct port for CHIRP transducers). This means integrating the transducer into your system is straightforward – just plug it in and configure the corresponding channel on your display. Raymarine’s software will auto-detect the TM265LM and offer setups for the Low and Medium channels. You can view both channels simultaneously in a split-screen – for instance, Low CHIRP for the broad view and Medium CHIRP for the details – or toggle between them as needed.

With the Raymarine TM265LM on your transom, your boat becomes a true “sonar station” capable of exceptional performance: seeing fish at 500+ meters, distinguishing single fish within bait schools, tracking the bottom from the shallows to the abyss. This equipment is favored by serious offshore anglers – especially those after trophy fish like swordfish, tuna, or deepwater groupers, where being able to probe the depths is crucial. With it, there’s no compromise: you get as much information as possible below you, making your fishing more efficient and your navigation safer when it comes to avoiding submerged hazards or piloting over complex terrain.