ST50 Plus Tridata display speed is 50% low

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum hwturn,

As you have inferred, the problem of low speed being reported following calibration may be rooted in the transducer or speed sensing instrument. Should you have
- replaced the speed/temp insert with a speed/temp insert of the correct length ... i.e. the speed/temp insert's paddlewheel extends slightly out of the transducer's housing,
- have oriented the speed/temp insert within its housing such that the transducer's orientation arrow is facing forward and parallel to the keel,
- have verified that no hull features or marine growth are interfering with the smooth flow of water the
- and the problem persists,
then the fault would appear to have been isolated to the ST50+ Tridata. Unfortunately, Raymarine can no longer service ST50/ST50+/ST60/ST60+ instruments, necessitating that the ST50+ Tridata instrument be replaced.

Please note that the i50/i60 instruments are designed to essentially be drop-in replacements for ST60/ST60+. The communications interfaces of the i50/i60 instruments will support either SeaTalk or SeaTalkng communications protocols. A SeaTalkng Spur to SeaTalk Flat 3-Pin Adapter Cable is supplied with the i50/i60 instruments to facilitate daisy chaining the i50/i60 instruments to ST60/ST60+ instruments, ST600x/ST700x/ST800x autopilot control head (where x= 0, 1, or 2), D244 SeaTalk Junction Blocks, etc.