Downhill Starts -- the Search for Clear Air

Downwind starts make even the best tacticians nervous. In an upwind start, as long as reasonable spacing is maintained, and you start on time, you can at least be assured of a lane that provides clean air and full speed, the primary goal of all starts. Volumes have been written about proper technique, tactics, and strategy for upwind starts. Off-wind starts (starts in which the first mark can be reached without tacking), on the other hand, involve essentially only one lane until the breeze is far enough aft that a gybe will be necessary.

Clear air and room to sail are hard to come by. They are a special beast with lots of variables with little in the literature to provide guidance.

It’s only in point-to-point races, the “navigators” format where government marks are used, or casual weeknight races where off-wind starts are encountered. With renewed popularity of these formats, I thought it would be worthwhile to try to ascribe some method to the madness.

I find it helpful to divide downwind starts into three zones. Zone 1 is angles from 40-80 true wind angle (relative to the course to the mark): the close reaching zone. Zone 2 is true wind angle (TWA) from 80-140: the beam reach to run zone. Zone 3 is 140-160 TWA: the run zone where a gybe will be involved. As always, the strategy (or where you want to start) is the easy part. Tactics, or how you execute the job of getting your boat to that point, are the hard parts.

The Favored End

Unlike upwind starts where the favored end of the line is the upwind end, in reaching and one-gybe runs (zones 1 and 2), the favored end is simply the one closest to the mark. Unless the line is grossly out of square, the more important overriding concern is getting clear air, which means you will generally be starting on the upwind end of the line. If the start is a true run (zone 3), then the favored end is the end furthest downwind, and it is worth considering a start there.

Zone 1

Start just ahead and to leeward of the pack. You don’t need to be the weather boat, because your apparent wind will be far enough forward to maintain clear air. If you get headed, the boats above will fall in. If you get lifted, you will have a faster reaching angle and shorter distance to the mark. The only exception is if the boat (right hand) end is much closer to the mark; then you will have to be right at the boat.

Zone 2

You must start directly at the windward end of the line (the righthand or boat end in the diagrams) and maintain a high lane to get to weather of the pack. This is the only way to insure clear air, even if you have to sail above an ideal course to the mark.

Zone 3

Start at an end, not in the middle. This is the quickest way to insure clear air. Consider which end is farther downwind. If it is 10 degrees or more favored, this is the place to be.


When starting in zones 1 and 2, it is easiest to control the fleet from a leeward position. From here you can head up to slow down and use your luffing rights to clear space. It is also important to know the close-hauled layline to the end where you are starting. If you get below this, you are vulnerable to weather boats. If you get too far above, leeward boats will control you. In a zone 1 start, the key is to bear off with plenty of time to get up to full speed; don’t be luffing up at the gun. In a zone 2 start, hold high until you reach a clear lane. Delay the spinnaker set until a clear lane is established and you are confident that no one can roll over the top of you.

In a zone 3 start, consider staying to weather to guarantee clear air and the ability to set a spinnaker. If starting at the left-hand end, think about a starboard approach to control the fleet with a gybe-set around the mark. This insures clear air and a free lane and may cause considerable consternation among the pack of port tackers trying to start at that end. Regardless of approach, set the spinnaker early, well before the gun if possible, so that the boat is up to full speed.

~David Flynn For more Quantum Racer's Edge stories, click here.