How is VMG calculated?
The northward component of the boat’s velocity vector is found by multiplying the boat speed (VB) by the cosine of the angle between the true wind direction (north) and the sailboat’s heading. In this case, the optimal VMG is obtained on a heading of 60 degrees from the true wind (60 degrees NE or 300 degrees NW).
Is a higher VMG better?
The rule of thumb is the lower the angle, the faster the boat will go, but it will be sailing further away from the mark. The higher the angle, the slower the boat will travel, but it will be sailing a more direct route to the mark. The crew therefore need to balance this trade-off between true boat speed and VMG.
What does SOG stand for in boating?
SOG. Speed Over Ground. This differs from boat speed- so for example if your boat is stationary in the water, it may still be moving in relation to the land due to current and wind etc.
How is VMG sailing calculated?
I plugged the numbers into this formula: (Boat speed at 8 degrees above dead downwind) x COS (the degrees above dead downwind) = VMG: 4.2 x COS (8) = 4.16 (VMG) (Boatspeed at 30 degrees above dead downwind) x COS (30) = VMG: 5.2 x COS (30) = 4.5 (VMG).
What is VMG in Prada Cup?
VMG: Velocity Made Good (VMG) at True-Wind-Angle (TWA): Velocity Made Good (VMG) is calculated in this case as the direct upwind or downwind component of velocity, depending on leg of the race course.
What measures speed over ground?
GPS speed, meaning Speed Over Ground (SOG), is a measure of our total speed over the surface of the earth, regardless of how that speed was accomplished, whether from our own propulsion, wind, currents, or any other source.
What is STW in Marine?
Speed Through Water (STW) is the speed of the vessel relative to the water. It is possible for the STW to be zero while the SOG is 5 knots, for example if the boat was drifting in a 5 knot current.
What is a VMG and where does it start?
Our starting point is wherever we are when we decide to sail a course that takes us off the rhumb line. VMG stands for Velocity Made Good , which is the progress that we’re actually making towards our destination, that is our speed along the rhumb line. We want to make this as large as possible.
What is the difference between VMG and boat speed?
VMG stands for Velocity Made Good , which is the progress that we’re actually making towards our destination, that is our speed along the rhumb line. We want to make this as large as possible. Boat Speed is the speed that the boat is making over the ground along its current course.
How much speed do you need to maintain VMG?
The boat speed needed to make 6 knots VMG is 6.9 knots. Looking at the percentage column of the table we can see that for course offsets of up to 15 degrees we only need a speed increase of less than 4% to maintain VMG, and even at 25 degrees away from the rhumb line course we need to gain just over 10%.
What is the difference between velocity made good and VMC?
The term Velocity Made Good (VMG) is often confused with term Velocity Made good on Course (VMC), and often used interchangeably. VMC is the speed component in the direction of a mark. If the course deviation is