Raymarine ST900/P120 Speed & Temp Thru-Hull Transducer Retractable w/13.7M (45') Cable
Raymarine ST900/P120 Speed & Temp Thru-Hull Transducer Retractable w/13.7M (45') Cable — Product description
Upgrade your boat's navigation with the precision and reliability of a thru-hull speed and temperature sensor designed for serious mariners. This retractable model delivers unmatched responsiveness from idle speeds up to high-velocity runs, ensuring you always know your boat's performance without guesswork. Its sleek, low-drag design integrates seamlessly into fiberglass or metal hulls, making it a favorite among sailors, racers, and cruisers who demand accuracy in dynamic conditions.
Superior Speed Detection That Starts Fast and Stays True
What sets this sensor apart is its advanced Gen2 paddlewheel technology. Unlike older models that lag at low speeds or falter at high ones, it kicks in reliably at just 0.3 knots and holds steady through 45 knots. Imagine docking with confidence or pushing limits on open water—every reading is smooth, linear, and trustworthy. Pair that with rapid water temperature updates, and you've got real-time data for optimizing fuel efficiency, engine performance, or even fishing spots where temp changes signal bites.
Streamlined Design for Minimal Drag and Maximum Protection
Crafted to hug the hull with only a 5mm protrusion, this low-profile thru-hull unit cuts through water like it's not even there, preserving your boat's speed potential. The retractable valve is a game-changer: pull the core for cleaning or winter storage, and it seals tight to keep bilge water at bay. Choose plastic housing for versatile fiberglass setups or bronze for metal hulls—either way, durability meets everyday boating demands.
Effortless Integration with Your Raymarine Setup
Analog output makes it plug-and-play with popular displays like i40, i50, or iTC-5 instruments, plus it's backward-compatible with legacy Raymarine systems. For those upgrading older Airmar P120 or B120 housings, the ST900 core drops right in—no major refits needed. This modularity saves time and hassle, letting you focus on the water instead of wiring.
Pro Tips for Installation and Peak Performance
Mount it forward of props and keels for clean water flow, ideally at the hull's flattest spot below the waterline. Drill a precise 51mm (2-inch) hole, bed it in sealant, and secure with the included nut. During install, flush the paddlewheel regularly to fend off marine growth—freshwater rinses after saltwater trips keep it spinning like new. In cold climates, retract it fully to avoid freeze damage. With a generous 13.7m cable, routing to your helm is straightforward, even on larger vessels.
- Best for: Sailboats, power yachts, fishing rigs—any hull craving precise speed logs.
- Temp sensing shines: Tracks shifts from 14°F to 104°F, vital for engine cooling or thermocline hunting.
- Maintenance hack: Valve lets you service without hauling out—perfect for liveaboards.
Real-World Reliability from Seasoned Boaters
Mariners rave about its low-speed startup, which outpaces competitors during tight maneuvers or light winds. High-speed linearity means GPS cross-checks match perfectly, building trust in your data. Whether racing around buoys or cruising coastal waters, this sensor proves why Raymarine leads in marine tech—robust, responsive, and built to last through salt, sun, and storms.
Frequently Asked Questions
Can this transducer be used on both fiberglass and metal hulls?
Yes, the plastic housing version works great on fiberglass, while bronze options suit metal hulls. Always match the housing to your boat's material for optimal sealing and performance.
How does the retractable feature work for maintenance?
The built-in valve closes automatically when you retract the paddlewheel core, preventing water from entering the hull. This allows easy cleaning or replacement without dry-docking.
What's the minimum speed it accurately measures?
It delivers precise readings starting at 0.3 knots, ideal for slow-speed scenarios like anchoring or drifting.
Is it compatible with older Raymarine instruments?
Absolutely—its analog output connects seamlessly to legacy systems as well as newer i-series displays.
How do I prevent fouling on the paddlewheel?
Rinse with freshwater after use, retract during storage, and inspect seasonally. Antifouling paints compatible with transducers can extend clean intervals.
Does the cable length support larger boats?
At 13.7 meters, it's plenty for most setups, reaching from bow-mounted sensors to aft helms on mid-sized vessels.
ST900/P120 Speed & Temp Thru-Hull Transducer Retractable with 13.7M (45') Cable
Speed performance has been taken to the next level with the ST900 Speed/Temperature sensor. Featuring the new Gen2 Paddlewheel, the ST900 outperforms all other paddlewheel sensors for responsive startup and linearity. The Gen2 Paddlewheel begins delivering accurate speed reporting as low as 0.3 knots and maintains smooth speed output through 45 knots.
Available with a plastic or bronze transducer housing, they sit nearly flush with the boat's hull and minimize drag with only 5mm (3/16") extending outside the hull. The housing has a valve assembly that helps to minimize water ingress in the bilge when the sensor is removed for routine maintenance of the paddlewheel.
Features:
- Speed and fast-response water temperature sensor
- Analog output for use with Raymarine instruments like i40, i50, iTC-5, and legacy systems
- Retractable for easy maintenance
- ST900 transducer core is retrofittable into existing Airmar P120 and B120 transducer housings
Specifications:
- Plastic
- Hull Material: Fiberglass/Metal
- Cable Length: 13.7M (45')
- Records: Speed/Temperature
- Hole Size: 51 mm (2")
- Mounting Style: Low Profile Thru-Hull
- Speed Range: 0.3 to 45 knots (.34 to 52 MPH/.55 to 83 KPH)
- Temperature Range: -10° to 40°C (14° to 104°F)
SKU: NVN-107014
MPN: E70673
UPC:
Technical specifications
| Brand | Raymarine |
| Model | Raymarine ST900/P120 Speed & Temp Thru-Hull Transducer Retractable w/13.7M (45') Cable |
| SKU / MFR# | 107014 |
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