ST50 log overreading

[Peter]

Aplogies, this post should have been here not in the liveaboard forum.
Got a ST50 nav system on my yacht, up until I lifted the boat for wash and antifoul the log worked OK. Now back in the water the log reads approx 2x the GPS reading. Great when sailing but has the potential to cause major problems. Before washing the hull down the log was jammed with marine life and was blasted with the jet wash by the yard. Any clues on why and and fixs

Thank

Peter

 

[Phoenix of Hamble]

It can be calibrated..... if you read the manual, it tells you how... if you don't have the manual it can be downloaded from the Raymarine US site.....