Simrad B258 Bronze Thru-Hull 9-Pin

Unlock Precision Depth Tracking for Your Sportfishing Adventures

Imagine cruising at high speeds across open waters, confidently tracking the seabed and structures up to 1,640 feet deep, all while monitoring water temperature changes that signal prime fishing spots. The Simrad B258 Bronze Thru-Hull stands out as a rugged, high-performance sensor designed for serious anglers and boaters who demand accuracy without compromise. Crafted from durable bronze, this thru-hull mount thrives in saltwater environments, delivering reliable data from slow trolling to blistering planing speeds.

Unlike basic transducers that falter in rough conditions or at speed, this unit shines with dual-frequency operation, providing sharp target separation in shallows and solid bottom lock in the depths. It's the go-to choice for vessels equipped with fairings, ensuring streamlined performance that minimizes drag and maximizes sonar clarity.

Core Features That Drive Superior Results

• Dual-Frequency Powerhouse: Operates at 50 kHz for wide-area deep-water coverage (typically around 35-degree beam) and 200 kHz for pinpoint detail in shallows (about 10-degree cone), balancing versatility across fishing scenarios.
• High-Speed Stability: Maintains precise echosounding from 1 knot up to 45 knots, with exceptional performance beyond 30 knots when paired with a proper fairing block.
• 1kW RMS Output: Packs serious punch for penetrating deep waters, ideal for offshore bottom fishing, wreck hunting, and structure scanning.
• Integrated Depth and Temperature Sensing: Single compact unit handles both, freeing up hull space and simplifying wiring for cleaner installs.
• Bronze Construction: Corrosion-resistant alloy built for long-term exposure to harsh marine conditions, including constant submersion and biofouling pressures.

Performance Tailored to Real-World Fishing Demands

In shallow bays or coastal zones under 100 feet, the 200 kHz mode excels at revealing bait schools, drop-offs, and individual fish arches with crisp resolution. Switch to 50 kHz for bluewater pursuits, where it locks onto rugged seabeds, ledges, and pinnacles at extreme ranges—perfect for targeting snapper, grouper, or swordfish holds.

Speed is no enemy here. The streamlined design, optimized for thru-hull mounting with a fairing, reduces cavitation and aeration, ensuring steady pings even as your vessel planes out. Boaters report consistent bottom tracking during high-speed transits, a game-changer for tournament pros covering vast search areas quickly.

Environmental toughness is baked in: the bronze housing shrugs off impacts from debris, temperature swings, and galvanic corrosion, outlasting plastic alternatives in salty, unforgiving seas.

Installation Insights for Optimal Setup

Mounting a thru-hull like this requires hull deadrise consideration—aim for a fairing that matches your boat's angle (up to 25 degrees typically) to keep the face perpendicular to the water flow. Forward-facing installs minimize turbulence from props, and always bed the unit in marine sealant for a watertight seal.

Pro tip: Position it ahead of thru-hull fittings or struts to avoid interference bubbles. Cable routing through bulkheads keeps things tidy, and a 9-pin connector ensures plug-and-play compatibility with modern sounders.

Why It Excels Over Standard Sensors

Many entry-level transducers lose lock at speed or depth, but the B258's 1kW power and bronze durability handle professional demands. It's not just about specs—it's about trust in split-second reads during a drift or troll, helping you drop lines exactly where structure meets productivity.

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