Raymarine Nylon Thru-Hull Speed Transducer, For ST70, ST60+, ST290, 20m Cable

Overview

The Raymarine E25025 is a nylon thru-hull speed and temperature transducer with a 20 m cable for Raymarine instrument systems. It gives the boat speed-through-water data needed for trim, sail performance, current comparison, and everyday navigation, while also reporting water temperature where the connected display supports it.

This is a P17-style thru-hull sensor with a retractable insert, so it is suited to permanent below-waterline installation rather than a transom or in-hull mount. The 20 m cable, roughly 65 ft, gives enough reach for many sailboat and powerboat layouts where the display or converter is not close to the transducer location.

Fit details matter before drilling: this transducer uses a 2 in installation hole and is listed for aluminum and fiberglass hulls. It is commonly used with Raymarine ST40, ST60+, ST290, and ST70 instrument installations, with ST70 systems requiring the separate ST70 Speed Pod.

Key features

• Measures speed-through-water and water temperature for compatible Raymarine instrument displays and converters.
• Through-hull mounting places the paddlewheel sensor in clean water flow below the hull for steadier speed readings.
• Retractable insert supports practical service access for cleaning the paddlewheel when fouling affects speed data.
• 20 m cable length helps with runs from the hull location to the helm, nav station, or instrument converter.
• 2 in hole requirement gives installers a clear fit check before replacing an older speed transducer or planning a new installation.
• Compatible with aluminum and fiberglass hulls when installed with the correct marine sealing and mounting practices.
• Works with Raymarine ST60+, ST290, and ST70 systems when the required ST70 Speed Pod is used.

Installation and setup

This transducer is intended for a thru-hull location where the paddlewheel can stay in smooth water flow while the boat is moving. On sailboats, that usually means avoiding keel turbulence, through-hull fittings, and trailer bunks. On powerboats, the mounting spot should stay wet and clear of aerated water at typical running speeds.

The 2 in hull opening should be planned carefully before removal or replacement work begins. As with any below-waterline fitting, installation should use the correct bedding compound for the hull material and should allow access inside the boat for tightening, inspection, and later service.

Compatibility and fit

The E25025 is a good match for boats maintaining or updating a Raymarine analog instrument setup where speed-through-water remains important. It can support cruising, racing, and fishing use where GPS speed alone does not show current effect or true boat performance through the water.

For ST70 installations, the separate ST70 Speed Pod is required. For newer Raymarine instrument networks, compatibility may depend on the display or converter being used, so the full instrument chain should be checked before ordering.

Maintenance and care

Like all paddlewheel speed sensors, this unit depends on a clean, freely turning wheel. Marine growth, paint buildup, or debris can reduce or stop speed readings, so periodic inspection and cleaning should be part of normal hull and instrument maintenance.

When hauled out, keep the outside face and paddlewheel area clean and avoid heavy antifouling buildup on moving parts. Inside the boat, inspect the cable route and the through-hull area during routine bilge checks, especially after rough passages or service work nearby.