[dcb]

I'm not so sure, I would use the water speed signal if it is already there just for convenience, but distance made good is distance made good.

Case and point, kill the engine and float back to the ramp and the whizweel will indicate 0mph and 0 mpg the whole way back, and the gps based speed signal will give you the actual infinity mpg and actual speed on the way back, just like EOC.

I mean who really cares how fast the current is going for efficiency? Your destination is still x actual miles away, and you still want to find the best way to get to that actual point with the least gas and it has to be in relation to actual miles, not water flow miles.

I don't see the fascination with water speed, at least not enough to buy a water speed sensor over a gps module, or why it is of any use except as an approximation of actual speed.