How to Calculate VMG

When sailing, it is often beneficial not to sail at your target destination. It is not possible to sail directly upwind, and sailing directly downwind can often be dangerous. Instead, by calculating Velocity Made Good (VMG), you can find out if there is a more efficient heading to reach your destination.

Instructions

1. Find your course offset by subtracting your course heading from the direct heading to your destination.

2. Multiply your boat's actual speed by the cosine of your course offset. This is your velocity made good.

3. Multiply your boat's actual speed by the sine of your course offset. This is your cross track error.

4. The course track error tells you how far off course you will travel in relation to the VMG while traveling along this bearing.

5. An ideal heading can be found by multiplying boat speeds at varying headings by the cosine of course offsets at those headings and choosing the optimal VMG.

References

• Why VMG Matters
• Printable Yachting VMG Reference Chart