Raymarine B75LH 12DEG Pair Thru Hull Chirp Transducers

Upgrade your vessel's sonar capabilities with these precision-engineered thru-hull transducers designed for serious anglers and navigators who demand crystal-clear underwater imaging. Crafted from durable bronze, they seamlessly integrate into fiberglass or wood hulls, delivering reliable performance even in demanding marine environments. Whether you're chasing trophy fish in deep offshore waters or mapping precise contours along the bottom, these transducers provide the edge you need for successful outings.

Superior Chirp Technology for Unmatched Detail

At the heart of these transducers lies advanced Chirp functionality, sweeping across broad frequency bands to produce hyper-detailed sonar returns. The low-frequency range excels at penetrating deeper waters, revealing structure and bait schools from afar, while the high-frequency band sharpens focus on individual targets and wrecks. This dual-band approach minimizes clutter and maximizes target separation, helping you spot fish that traditional fixed-frequency sonar might miss.

• Low-frequency coverage: Expansive beam from 32° to 21°, ideal for wide-area scanning in depths over 1,000 feet.
• High-frequency precision: Narrow beam tapering from 15° to 9°, perfect for pinpointing game fish near the bottom.
• Integrated temperature sensing for real-time water column data, aiding in thermocline detection and lure selection.

Robust Build for Long-Lasting Marine Use

Engineered with a rugged bronze housing, these thru-hull mounts withstand the corrosive punch of saltwater while maintaining acoustic integrity. The 12-degree design optimizes performance on hulls with moderate deadrise angles, ensuring a clean signal path without dead zones. Paired with a standard power rating, they handle high-output sounders effortlessly, and the included Y-splitter cable simplifies dual-transducer setups for side-by-side or forward/aft configurations.

Installation is straightforward for DIY boaters: Drill a precise fairing hole, bed the unit in marine sealant, and route the cable cleanly through bulkheads. Pro tip: Align the transducer parallel to the waterline at cruising speed for optimal beam projection—many users report a 20-30% improvement in bottom tracking after fine-tuning the angle.

Real-World Applications and Angler Insights

Offshore captains swear by this setup for tuna runs and billfish pursuits, where the narrow high-frequency beam cuts through thermoclines to highlight hooks-ups amid bait balls. Inshore, it shines for redfish ambushes along structure-rich flats, combining depth accuracy with temp data to predict feeding zones. Compared to pod-style transducers, thru-hull models like these offer less turbulence-induced noise, leading to cleaner screens at displacement hull speeds above 15 knots.

For multi-engine setups, running a pair—one forward, one aft—creates a comprehensive coverage envelope, eliminating blind spots common in single-unit installs. Anglers often pair them with high-end chartplotters for CHIRP-enabled networks, unlocking features like ForwardScan for safe anchoring in unfamiliar bays.

Maintenance Tips for Peak Performance

To keep your sonar humming season after season, inspect the face annually for marine growth and gently clean with a soft brush and mild vinegar solution. Avoid high-pressure washers, which can damage the ceramic element. During haul-outs, apply a fresh coat of anti-fouling paint around the thru-hull flange to deter barnacles. With proper care, these units deliver years of trouble-free service, outlasting cheaper plastic alternatives in harsh conditions.