CPT-120 CHIRP Bronze Thru-Hull Transducer (DownVision)

The CPT-120 is Raymarine’s dual-channel CHIRP transducer engineered to give your boat both crystal-clear DownVision™ imagery and reliable fish-finding capability in one thru-hull unit. This bronze transducer contains two separate sonar elements: one is a conical High-CHIRP fishfinder element (operating in roughly the 170–230 kHz range) for depth and fish targets, and the other is a wide fan-shaped DownVision element (around 320–380 kHz) for scanning the bottom with near-photographic detail.

By installing the CPT-120, you essentially gain “X-ray vision” beneath your boat: the DownVision channel will display the structure of the seabed – rocks, ledges, wrecks, vegetation – in a photo-like manner, while simultaneously the traditional CHIRP channel will show fish arches and digital depth readouts so you can pinpoint fish and know exactly how deep they are. The DownVision channel has a maximum effective depth of about 180 m (600 ft) depending on conditions, which covers most inshore and many offshore fishing grounds. Meanwhile, the high-CHIRP fishfinder channel can reach around 275 m (900 ft), ensuring you maintain depth tracking even when the detailed channel can’t go further.

High-Speed Fairing Block: The CPT-120 comes bundled with a specially contoured fairing block for external hull mounting. This fairing serves two important purposes:

1. Angle Correction: It allows the transducer to be mounted on hulls with deadrise up to 25° while keeping the internal elements pointed straight down. In other words, the wedge-shaped fairing compensates for your hull’s angle, so the sonar beams shoot vertically. This makes the CPT-120 versatile across many boat types – from flat bottom boats to moderate V-hulls.
2. Streamlined Flow: The hydrodynamic shape of the fairing smooths water flow around the transducer face, reducing turbulence and air bubbles at speed. This is crucial for maintaining a clean sonar signal when the boat is moving quickly (e.g., on plane). With the fairing, you can expect solid bottom lock and sonar returns even at speeds where other transducers might struggle.

The transducer itself is housed in a bronze body, chosen for its durability and proven performance in through-hull applications. Bronze is an ideal material for fiberglass and wooden hulls due to its strength and resistance to corrosion. (Note: On aluminum hulls, bronze must be isolated properly to prevent galvanic corrosion – Raymarine offered a plastic thru-hull variant for metal boats, known as the CPT-110. Owners of metal hulls should consider that, or ensure proper isolation when installing CPT-120.)

Compatibility & Use Cases: The CPT-120 is designed to work with the Raymarine CP100 sonar module as well as Raymarine MFDs that have built-in CHIRP DownVision sonar (such as the a68, a78, certain eS/gS Series units with DownVision). Connection is via a standard 9-pin plug – truly plug-and-play. Once connected to a CP100 or compatible display, the system will automatically utilize the two-channel input, giving you the option to view DownVision and conventional sonar side by side or blended.

Benefits of the CPT-120:

• Dual Sonar Capability: With one installation, you get two types of sonar. The advantage here is immense: you can confirm what you’re seeing. For example, DownVision might show a complex structure on the bottom; the fishfinder channel can then confirm if fish are holding around it (displaying arches). Conversely, if you see fish arches on the CHIRP, a quick glance at the DownVision panel can tell you if they’re near a tree stump, wreck, or just off a drop-off. It’s a one-two punch for situational awareness underwater.
• Exceptional DownVision Clarity: The wide-beam DownVision element operates on CHIRP pulses centered in the high kHz range, producing extremely high-resolution slices of the water column. The result is akin to a black-and-white photograph of the bottom. This high clarity is particularly useful for identifying bottom composition (hard vs. soft), recognizing man-made structure (like submerged roadbeds or wreckage), and even spotting schools of baitfish or individual gamefish in relation to the structure (they’ll appear as bright spots against the high detail background).
• Dependable Depth & Fish Tracking: While DownVision provides detail, the conventional CHIRP sonar provides strong depth tracking and target detection at greater ranges. The CPT-120’s CHIRP element ensures you maintain an accurate depth reading up to ~900 ft and can detect fish well beyond the DownVision limit. This duality means you won’t lose situational info – you always have a fallback to the traditional sonar when probing deeper waters, ensuring safe navigation and continuous fishfinding intel.
• Performance at Speed: When installed with the fairing, the CPT-120 is built to hold the bottom even when you’re cruising between spots. Many transducers lose bottom lock or display clutter at higher speeds due to aeration; the CPT-120’s design mitigates that. So you can confidently monitor depth to avoid shallow hazards when running, and even mark fish or bait while on the move, giving you more time fishing and less time idling.
• Seamless Integration with Raymarine Systems: As an official Raymarine transducer, the CPT-120 integrates perfectly with the user interface of Raymarine displays. You can utilize advanced features like split-screen zoom, A-Scope (real-time sonar column), and target depth tracking on fish symbols. If connected to a Raymarine MFD, you can also leverage waypoint marking directly on sonar imagery – see a big fish arc or interesting structure on DownVision? Just touch the screen to drop a waypoint for later. The synergy between the CPT-120 and Raymarine’s software ensures you get the most out of the hardware.

In summary, the Raymarine CPT-120 CHIRP Bronze Thru-Hull Transducer is a top-tier sonar sensor for boaters who demand superior imaging and performance. It’s particularly valuable for dedicated anglers and exploration enthusiasts who want to see beneath their boat in extraordinary detail while still tracking fish and depth reliably. With CPT-120 installed, your chartplotter/fishfinder becomes a powerful window into the underwater world – revealing structure, locating fish, and helping you make informed decisions on the water for both safety and success.