Precision Speed and Temperature Sensing for Serious Boaters
Upgrade your vessel’s instrumentation with the Raymarine ST900, a thru-hull sensor that delivers unmatched accuracy in speed and water temperature readings. Designed for sailors and powerboaters who demand reliability, this low-profile plastic housing integrates seamlessly into your hull, providing real-time data to enhance navigation and performance tracking. Whether you’re racing, cruising, or fishing, the ST900’s Gen2 paddlewheel technology ensures responsive startup—even at speeds as low as 0.3 knots—and smooth linearity up to 45 knots.
Key Advantages Over Traditional Sensors
Superior Low-Speed Performance: Starts delivering precise data from just 0.3 knots, ideal for light-wind sailing conditions where every knot counts.
Minimal Drag Design: Only 5 mm protrudes outside the hull, reducing resistance and maintaining your boat’s hydrodynamic efficiency.
Integrated Water Valve: Allows safe paddlewheel removal for cleaning without flooding the bilge, simplifying maintenance during long voyages.
Fast-Response Temperature: Captures water temp changes with ±0.5°C accuracy across a wide range (-10°C to 40°C), perfect for optimizing engine performance or monitoring fishing zones.
Gen2 Paddlewheel: Industry-Leading Innovation
The heart of the ST900 is Airmar’s next-generation Gen2 paddlewheel, engineered for exceptional sensitivity and linearity. Unlike older designs that falter at low speeds or top out prematurely, this paddlewheel excels across the full range—from gentle drifts to high-speed runs. Boaters report noticeably smoother speed logs on multifunction displays, leading to better tactical decisions in regattas or efficient fuel management on long passages.
Retrofit Compatibility for Easy Upgrades
Planning a sensor refresh? The ST900’s retractable insert drops right into existing Airmar P120 or B120 housings, saving time and installation hassle. Its analog output integrates effortlessly with legacy Raymarine systems or third-party instruments, making it a smart choice for mixed setups.
Technical Specifications at a Glance
Feature
Details
Cable Length
20 meters
Sensing Functions
Speed and Temperature
Hull Hole Size
51 mm (2 inches)
Housing Material
Plastic
Mounting Type
Low-Profile Thru-Hull
Output Protocol
Analog
Retractable Design
Yes, with valve
Speed Range
0.3 to 45 knots (0.34 to 52 MPH / 0.55 to 83 KPH)
Temperature Accuracy
±0.5°C (±1.8°F)
Operating Temperature Range
-10°C to 40°C (14°F to 104°F)
Why Choose the ST900 for Your Boat?
Investing in the ST900 means gaining a sensor that punches above its weight in durability and precision. Its robust plastic housing withstands harsh marine environments, while the 20-meter cable offers flexible routing to your helm station. Regular paddlewheel maintenance is straightforward—simply retract the insert, clean away marine growth, and reseat it securely. This level of performance and ease has made it a favorite among competitive sailors and weekend adventurers alike, ensuring your speed and temp data is always spot-on for safer, faster boating.
Frequently Asked Questions
What makes the ST900’s speed range better than other thru-hull sensors?
The Gen2 paddlewheel provides responsive readings from 0.3 knots up to 45 knots, offering superior low-speed startup and high-speed linearity compared to standard paddlewheels.
