@idefix37 Actually, very easily. After racing and/or cruising the boat for a season or 2, you should have a good idea of what the boat's average boat speed is. Also, if you have "polars" from a Velocity Prediction Program used by a Naval Architect in designing the boat, you can use the polar data and the forecast windspeed to set your boat speed. I use a boat's "Polars" all of the time when delivering boats that I know very little about.