Group: Forum Members
when you find out why this is happening, please post it. We have a similar issue(s), though we use our chart plotter trip log for the mileage.
Our chart plotter (Northstar M120), our Raymarine Autopilot (ST3G), and our Tacktick wind and speed instruments and all interconnected (as is our Icom VHF and AIS transponder).
Our chart plotter will (for example) show a SOG of 7.5kt, the Raymarine display shows 6.9 as 'speed ', while the Tacktick shows 6.5kn (through the water).
Just to add to the interest, while at anchor (0kt speed) the Tacktick will display two different wind speeds and directions for apparent and true.