Dmitry Shteyn — Finding the Groove: VMG vs. Soaking in Downwind Dinghy Racing

The Downwind Dilemma

One of the most frequent questions I get during our weekend clinics on Lake Mendota is simple but tricky: "Should I point at the mark, or should I head up to go faster?" In a dinghy, the answer is rarely a straight line. We are constantly balancing Velocity Made Good (VMG)—which is our actual progress toward the leeward mark—against our raw boat speed.

In the sailing world, we call this the trade-off between "soaking" (sailing deep and slow) and "heating it up" (sailing higher and faster). If you sail too deep, your sails stall, and your speed drops off a cliff. If you sail too high, you might be flying, but you’re traveling twice as much distance as the guy who just pointed his bow at the buoy.

Understanding the VMG Curve

Think of your dinghy like a bicycle on a hilly road. If you pedal straight up the steepest part, you go slow. If you zig-zag, you go faster but travel more miles. Downwind, your "hill" is the wind pressure.

In light air, specifically on our inland Wisconsin lakes where the wind can be patchy, you often have to "heat it up." By heading up 10 or 15 degrees, you create apparent wind across the sails. This keeps the flow attached and keeps the boat moving. In these conditions, a boat that tries to "soak" (sail directly downwind) usually ends up bobbing in place while the rest of the fleet sails around them.

However, as the breeze builds, the math changes. Once you have enough wind to keep the boat at its hull speed, every extra degree you sail away from the mark is wasted distance. This is where "soaking" becomes the winning play.

The Lake Michigan Plane

Let’s look at a concrete example from a Laser (ILCA) regatta I coached off the Milwaukee shoreline last summer. We had a steady 12-14 knot breeze with a bit of a chop.

In these conditions, the boats that tried to sail a straight line to the leeward mark were getting stuck in the troughs of the waves. Their bows would bury, and they’d lose momentum. The winners were the sailors who played the "S-turn." They would head up slightly to catch a wave—generating speed and getting the boat on a plane—and then, once they were flying, they would immediately "soak" down, using that momentum to sail deep toward the mark while staying on the wave.

This is the ultimate VMG technique: using bursts of speed to earn the right to sail deep. If you just sit there at a 180-degree angle to the wind, you aren't generating enough dynamic lift to get over the waves.

Strategic Soaking and Rule 17

When you are in a tight fleet, your choice of angle isn't just about the wind; it's about the boats around you. If you are the windward boat and you decide to soak deep to stay in a puff, you have to be mindful of the boats to leeward.

According to World Sailing's Racing Rules of Sailing (RRS) Rule 17, if a boat clear astern establishes an overlap to leeward within two of her hull lengths, she shall not sail above her proper course. However, as the windward boat, you have the right to soak as deep as you want, provided you don't infringe on their space or break Rule 11 (Windward/Leeward). Soaking is often a great defensive move to keep your air clear from boats behind you who are trying to "heat it up" to pass you.

When to Pivot Your Strategy

How do you know which one to pick? I tell my students to use the "pressure test."

• The Light Air Test: If your telltales are drooping or the boat feels "heavy," head up. Gain 5 knots of boat speed even if it means sailing 20 degrees off course. Speed is king in light air.
• The Heavy Air Test: If you are already planing or moving at max speed, look at the mark. If you can point closer to it without losing that plane, do it. Every yard you save is a yard your competitor has to sail.

On small lakes like Lake Wingra, the shifts happen so fast that your VMG angle might change every thirty seconds. You have to be active. You can’t just set the boom and relax. You should be constantly moving the tiller—heading up in the lulls to keep the boat alive, and soaking down in the puffs to make gains on the mark.

Safety and Stability

Remember that soaking deep, especially in a gusty breeze, puts you at risk of a "death roll" or an accidental gybe. As you sail deeper (closer to 180 degrees), the boat becomes less stable. Always keep your weight centered and be ready to trim the mainsheet quickly if the boat starts to oscillate. Safety is part of speed; a capsize is the worst VMG you can possibly have.