Velocity Made Good (VMG)

The speed at which a vessel is effectively moving towards its intended destination, factoring in both its current speed and the angle of travel relative to the wind or current.

Velocity Made Good (VMG) is a crucial concept in sailing and other forms of marine navigation, especially when travelling upwind or downwind. It refers to the component of a vessel’s velocity that is directly contributing to its progress towards a specific waypoint or destination. Unlike the boat’s actual speed through the water, VMG takes into account the direction of travel relative to the wind or current, making it a more accurate measure of how efficiently the vessel is moving towards its goal.

For example, when sailing upwind, a boat cannot sail directly into the wind and must instead “tack” or sail at an angle to the wind. While the boat may be moving at a good speed through the water, only a portion of that speed is actually helping it get closer to its destination. VMG helps sailors optimise their course by indicating whether they are making the best possible progress towards their goal, even if that means sailing at a slightly slower speed but on a more favourable angle.

In downwind sailing, VMG is also important, as sailing directly downwind may not always be the fastest route. Sometimes, sailing at an angle to the wind and gybing, can result in a higher VMG, as the boat speed is increased compared to sailing directly downwind. This is particually true when using asymetric spinnakars. By maximising VMG, sailors can ensure they are making the most efficient use of wind conditions to reach their destination as quickly as possible.