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VMG stands for Velocity Made Good and it’s an important concept in the sailing world. Essentially, it calculates how fast you are moving toward a waypoint as the crow flies, rather than how fast you are moving in a straight line. For example, if you are trying to get to a point that is due north, but are sailing at 45 degrees at 8 knots, how fast are you actually moving towards that point? If you’re having traumatic flashbacks to trigonometry class, you’re not alone.
Fortunately, our navigation equipment on board calculates VMG for us and it does it in real time. This is especially helpful as we have set a waypoint over by the Caribbean and can track our VMG towards that point. So far we’ve managed a great VMG while we’re on starboard tack and heading WNW, but that eventually brings us too far north, so we had to gybe and head back south today.
It was quite painful to watch our VMG drop into the 2-3 knot range today as we headed south, even though we were sailing at 7-8 knots. This was because we had to sail at a wind angle of about 120-150 degrees in order to prevent our genoa from being blanketed by our mainsail and meant that we were sailing much more south than west.
So we decided to try a new sail combination so that we could run deeper downwind: wing-on-wing. Now full disclosure, this isn’t the most efficient point of sail for a catamaran, and we don’t have equipment such as a whisker pole to run from the mast to the clew of the genoa that would help fully open up the genoa. But with all that said, what matters is VMG, and if we can maintain a higher VMG while making our way back south, I’ll take a bit of inefficiency.
We already had the barber hauler rigged up for the genoa and it was quite easy to rig up a preventer for the boom. Rather than grind the genoa, I set it with the barber hauler on the tack I wanted, and then slowly pulled the boom to windward using our traveler. Then I adjusted course so that we gybed the mainsail and set the autopilot to run on a consistent 175 deg wind angle on a port tack. The preventer is keeping the boom from moving around and preventing any accidental gybes, hence the name, and the barber hauler is keeping the genoa fairly open.
So far the results are good. We are heading more WSW towards our Caribbean waypoint and our VMG has jumped from 2-3 to between 6-8 while our Speed Over Ground has only suffered a bit. It may not be the most efficient way to sail, but as I’m quickly learning, all that matters is VMG baby and doing whatever it takes to get there.
On a side note… We are currently monitoring another sailing vessel on AIS that is projected to pass with 1-2 nm of us in the next half our or so. We have been trying to hail them for over an hour with no success. It’s amazing to me how two boats can come so close in the complete middle of the ocean, but it’s even more amazing to me that a boat can be out here without monitoring their radio. Fortunately, we’re on the ball and keeping a close eye on them!