[DG] [DG] Replacement ST 60+ Tri Data Speed sensing housing

[Derek - Raymarine - Moderator]

Hi mmichaelbrown

Thank you for your enquiry

There are several reasons the speed may be underreading, the cause could be mechanical, electrical or due to interference.

If mechanical, then it could be a worn shaft or paddlewheel impeller bearings - the paddlewheel may spin freely when spun by hand or blown, but in water could have higher friction and not spin so easily. So we suggest replace the paddlewheel and shaft, the service kit and replacement housing can be sourced at this link

If electrical, the transducer could be faulty and can be tested here . Alternatively, there could be an incorrect speed calibration factor used and this can be checked in the instrument calibration.

If interference, this could be caused by the transducer cable being coiled near other cables or sources of high signal amplitude or cables carrying high current possibly.

regards

Derek