Raymarine B17 Bronze Retractable Through-Hull Depth Transducer, For ST70/ST60+/ST290 Instruments, 200 kHz, 45 ft Cable

Overview

The Raymarine M78717 is a B17 bronze retractable through-hull depth transducer for Raymarine instrument systems. It is a depth-only transducer that operates at 200 kHz with a 13 degree beam width, giving boaters a dedicated depth signal for compatible analog instrument displays and interfaces.

This unit uses a 2-inch bronze through-hull fitting and is suitable for fiberglass and wood hulls. The retractable core lets the insert be removed for cleaning and service, which is useful when growth or debris affects readings and access from inside the hull is available.

A 15-meter, 45-foot cable with ISO female spade connectors is included on the transducer, giving installers enough length for many helm, cockpit, or instrument-panel runs without immediately planning an extension.

Key features

• Bronze through-hull depth transducer for fiberglass and wood hull installations.
• Retractable insert allows cleaning and maintenance from inside the vessel when the installation layout permits access.
• 200 kHz depth operation with a 13 degree beam width for use with compatible Raymarine instrument systems.
• 2-inch hull opening requirement helps confirm fit before replacing an existing through-hull or planning a new installation.
• 15-meter, 45-foot cable with ISO female spade connectors supports typical instrument runs on many sailboats and cruising powerboats.
• Compatible with Raymarine analog depth instruments and interfaces including i40 Depth, i50 Depth, iTC-5, ST60+ Depth, and other legacy instrument systems.

Compatibility and fit

This transducer is a good match for owners maintaining or upgrading a Raymarine instrument setup that needs a dedicated through-hull depth source rather than a multifunction sonar transducer. It is commonly used on sailboats and cruising boats where a low-profile through-hull installation is preferred over a transom-mounted sensor.

Before installation, confirm the display or interface accepts this analog depth transducer connection and that the hull material is fiberglass or wood. Bronze through-hull fittings are not generally selected for aluminum hulls because of corrosion concerns between dissimilar metals.

Installation and service

The installation requires a 2-inch hole through the hull and a dry, accessible interior location around the fitting. Bedding, tightening, and cable routing should follow normal through-hull installation practices for the vessel, with the cable protected from chafe and kept clear of high-current wiring where practical.

The removable core is helpful for seasonal cleaning and service, especially on boats kept in the water where marine growth can collect around sensors. Keeping the face of the transducer clean helps maintain consistent depth readings during coastal cruising, fishing, docking, and shallow-water navigation.