VMG Calculator
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Velocity Made Good (VMG) (knots): {{ vmg }}
Velocity Made Good (VMG) is a critical sailing metric that quantifies the speed at which a boat is moving directly towards its destination or mark, factoring in both the boat's speed and its angle to the wind. It's essential for racers and cruisers alike for optimizing course and sail settings.
VMG Formula
The formula to calculate VMG is as follows:
\[ VMG = BS \times \cos(TWA) \]
Where:
- \(VMG\) is the Velocity Made Good in knots,
- \(BS\) is the boat speed in knots,
- \(TWA\) is the true wind angle in degrees.
How to Calculate VMG
- Determine the boat speed in knots. For example, let's say the boat speed is 5 knots.
- Determine the true wind angle (TWA) in degrees. If the TWA is 30 degrees, for instance.
- Convert the TWA from degrees to radians, as cosine calculations are performed in radians.
- Calculate the VMG by multiplying the boat speed by the cosine of the TWA.
Example Problem
Given a boat speed of 5 knots and a true wind angle of 30 degrees, the VMG can be calculated as follows:
\[ VMG = 5 \times \cos(30^\circ) \]
Converting 30 degrees to radians (\(30^\circ \times \frac{\pi}{180} \approx 0.523599\)) and calculating:
\[ VMG = 5 \times \cos(0.523599) \approx 4.330127 \, \text{knots} \]
This calculation shows that, given the conditions, the boat's velocity made good towards the destination is approximately 4.33 knots.
Understanding VMG helps sailors to make informed decisions about adjusting their course and sail trim to maximize their speed towards the target, which is crucial for competitive sailing and efficient cruising.