Overview

The Raymarine E26005 is a transom-mount speed and water temperature sensor for ST40 instrument systems. It is the ST69 paddlewheel style sensor, so it reads boat speed and sea temperature at the stern without using a through-hull fitting. The sensor uses a 9 m cable and reads speed from 4 to 50 knots, which covers the normal operating range of many cruising, fishing, and performance boats.

This is an analog transducer for instrument displays rather than a standalone network sensor. That matters when you are replacing an older ST40 sensor or matching it to a compatible Raymarine instrument setup, because the mounting style, cable run, and instrument input all need to line up before you mount it on the transom and route the cable forward.

Key features

• ST69 transom-mount paddlewheel sensor for speed and water temperature
• Works with Raymarine ST40 systems and other compatible Raymarine analog instrument displays
• 9 m cable helps with runs from the transom to helm-mounted instruments
• Paddlewheel and housing sit close to the hull to help keep spray and drag down
• Built-in transom-angle adjustment helps when matching the sensor to the boat's stern angle
• Paddlewheel can be removed for cleaning or replacement
• Plastic housing stands up well to impact and chemical exposure around the transom

Compatibility and system integration

This sensor is used with Raymarine speed and bidata instrument displays that accept analog speed and temperature input, including ST40, i40 Speed, i40 Bidata, i50 Speed, and i50 Tridata. On i70 and i70s installations it is used through an iTC-5 converter, which is worth checking before ordering a direct replacement.

Installation and fit

Transom mounting makes sense on boats where you want speed and temperature data but do not want a fitting through the bottom of the hull. The bracket lets you set the sensor angle to suit the transom, and the cable can exit from the left side, right side, or top of the housing. That gives a little more freedom on sterns that already have ladders, trim tabs, drains, or trailer hardware nearby.

Maintenance and care

Like any paddlewheel sensor, it works best when the wheel spins freely and the sensing face stays clear of growth. Periodic cleaning is part of normal upkeep, especially on boats kept in saltwater. This sensor suits owners replacing an ST40 transducer, refitting a smaller instrument system, or adding basic speed and water temperature data at the helm without moving to a larger electronics package.