What is true wind?

True wind is what the wind is truly doing and it can be computed from the measured apparent wind by subtracting the vessels speed. For example, if the vessel was moving at exactly 5 knots and the wind was blowing in the exact opposite direction at 5 knots, then the WSO100 measured, or apparent wind speed would be 10 knots. If the boat speed of 5 knots was subtracted from the apparent wind speed, then the computed true wind speed would be 5 knots. Maretron display products (DSM150, DSM200, DSM250, and N2KView) always show true wind referenced to the bow of the vessel. In other words, you see the angle at which the true wind is striking the vessel relative to the bow of the vessel. It is important to note that the WSO100 doesn’t actually compute and transmit true wind speed, it is the displays that subtract the boat speed from the apparent wind and ultimately display true wind.