The d10 automatically based on the following priority:
1: If speed through the water is provided by an external system then that is used
2: If there is no speed through the water provided by an external system and a paddle wheel is connected then the paddle wheel speed is used
3: If there is no speed through the water then speed over the ground is shown. If there is speed over the ground from an external system then that is given priority over SOG from the internal GPS.