Downwind in Heavy Air

A San Juan 24 has lots of great features; however, stability going downwind in a strong breeze is not one of them. These are a few tips I’ve learned that help keep the boat upright in these conditions. Maybe these are well-known to almost everyone but perhaps one or two will be of use to somebody.

For starters, there are a couple of principles worth keeping in mind:

The boat has more than enough power. Once the wind reaches a certain point – to my eye, around when whitecaps start appearing – there’s more than enough wind force to power the boat to its maximum hull speed. Since you can’t go any faster than that (disregarding extraneous factors such as waves and current) it’s worth trading off a little power when necessary in order to maintain control. The boat will still be moving as fast as it can go.

Keep the keel and the wind more or less in alignment. That means heading fully downwind, which may seem obvious when talking about downwind sailing, but it’s doubly so in stronger winds. The keel is great when it serves as a blade slicing through the water but when the wind starts pushing too much laterally on the boat that blade becomes a lever and broaches quickly follow.

Here are a few things I do to implement these principles:

1) The spinnaker pole can go forward a foot or two from its usual setting. This will depower the chute a bit by blanketing it with the mainsail. If everything feels stable, you can always bring it back to its normal position. This is simply the first and probably easiest step you can take to reduce power.

2) Keep the pole lower on the mast than normal. Again, this will reduce power a bit. By keeping the spin lower it also is better positioned to drive the boat forward rather than introducing dynamics that might tend to take the boat in a different direction.

3) Steer dead downwind. Or at least nearly so. (This assumes that the next rounding mark is more or less dead downwind from the windward mark you’ve just rounded.) You may be thinking, Mark, you said this before so why are you repeating yourself? A couple of reasons. The principles above are intended to highlight the forces that are at play and that you have to balance; this is the how-to section. So head straight to the next mark. Moreover, you have more than enough power so you won’t go faster by heading higher, which means you’re sacrificing velocity made good by doing anything other than heading straight to the mark. This also sets you up to take advantage of the suggestions that follow. On the other hand, following a higher heading such as you would use in lighter winds can begin to set up a problematic chain of events.

4) Steer under the sail. Learning this one has been the single best aid to me of anything. You don’t have to constantly steer exactly toward the middle of the sail but at the first sign that the boat is becoming unstable or might be headed toward a round-up steer aggressively to the middle of the chute. And I mean aggressively; there’s a lot of force at work and things happen quickly so the boat needs to be stabilized right away. There can be a natural reluctance to change course from the one you want to follow. This is where you need to keep the bigger picture in mind; a 10 or even 20 degree course alteration for 10 seconds is nothing compared with the time you lose if a more serious problem develops. Plus, if you’ve been following a dead downwind heading, you won’t have deviated all that much from that course and can make it up fairly quickly.

5) Gybe early. You want to sail a dead downwind course anyway so as soon as you think you can do that on the other tack, go ahead and gybe. In addition to setting you up to be the inside boat at the next rounding, it is so much easier to gybe while heading dead down. It’s always a struggle to reset the pole on the other side but there’s absolutely no rush if you’re heading dead downwind. The boat will continue moving along just fine without the pole in place so everyone can wait for the moment when it’s easiest to get the pole back on. By contrast, gybing from an apparent wind heading of, say, 160 degrees on one side to 160 on the other side can be substantially more difficult because it’s almost impossible to find a point where the pressure can be relieved sufficiently to put the pole back in. Therefore, if you find yourself in this position, it often is best to assume a dead down course for the gybe, continue on that heading until the gybe is completed, and only afterwards assume your desired heading.

I hope that helps. See you on the water. Sometime.

Mark Bradner, Return