Raymarine ST900 Speed/Temp Bronze Thru-Hull, 13.7m Cable
- Brand:
- Raymarine
- Part no:
- E70686
Image: firstchoicemarine.com
Where to buy
Specifications
- Mount
- Thru-hull
- Sensor
- Paddlewheel
- Material
- Bronze
- Max speed
- 45 kt
- Retractable
- Yes
Raymarine's ST900 is a paddlewheel speed and water temperature sensor in a low-profile bronze thru-hull housing, supplied with 13.7 m of cable. The insert is retractable, and it is made to retrofit into Airmar P120 and B120 housings. It reads speed from 0.3 up to 45 knots. The housing sits almost flush, with about 5 mm outside the hull, and a built-in valve limits water entering the boat while the paddlewheel is out for servicing.
Our take
The valve assembly in the ST900 housing is meant to limit water entering the boat while the paddlewheel insert is out for maintenance, which makes a routine clean less of a worry. Its speed range starts at 0.3 knots, so slow manoeuvring still gets a reading.
From our buying guide
Speed sensors use a paddlewheel, or ultrasonic transducers with no moving parts. Both foul: Airmar says growth can impede or freeze a paddlewheel within weeks, and also reduces an ultrasonic sensor's performance.
Check before you buy:
- It suits your hull, since Airmar does not recommend its UDST800 for hulls designed to pull air under them.
- The housing suits your hull too. Airmar and Raymarine rule out plastic on a wood hull and bronze on a metal one.
- You'll calibrate it once fitted, since Raymarine says the reading depends on where it sits, the hull shape and the water flow.