VMG stands for "Velocity Made Good" and basically tells you the speed at which a boat is reducing the distance between themselves and the finish. For example, a boat that is going very fast, but in the wrong direction, could have a lower VMG compared to a boat going steadily in the right direction.

VMG has to be based on the boat's performance up til now, and we provide you with two different ways to compare VMG: "VMG since the start", which gives an indication of a boat's average performance from the beginning of their voyage. Or "Recent VMG" mode which is based only on the last few position reports and gives you an an indication of a boat's current performance. You'll see a button allowing you to switch between these two modes.

Each boat has a TCF (time correction factor) based on the size of boat, type of sail etc. It allows a fair race to take place between different kinds of boats. Much like a golfing handicap allows players of different skill levels (size of boat) to play against each other, without the most highly skilled player (biggest boat) winning all the time.

The Estimated Finish Time is the time when we think boat will actually reach the finish - the time the boat will physically arrive there. The Corrected Finish Time takes the finish time, and applies (multiplies by) the TCF (handicap).

The leaderboard is then sorted in that order, so you can see who will "win" out of the group of boats. This is an imaginary time, but allows comparison of a fleet of disparate boats.