So, I'm a racing nerd. I read books on it. So, I've read that when anticipating a persistent shift it is wise to "sail to the shift" as early as possible. In other words, to tack into a header early in the windward leg to get over to the side of the course that allows you to take full advantage of the shift. Why do this early? Why not in the middle of the windward leg? Geometrically, it seems the same. What am I missing?
Sailing to the shift
- Thread starter markwbird
- Start date
If the shift is great enough to allow you to fetch the weather mark on the alternate tack, then it'd be pointless to continue even a few seconds on the "knocked-down" tack. This is not the same thing as oscillation. But also, as as a matter of principle, you never want to be sailing "away" from the mark when the other tack will take you more toward it.
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It works like this.
If you KNOW or predict (and in some placed you can predict this) that the wind is going to go say LEFT at noon, it makes sense to be left on the course. This leftie will knock you hard, but a tack and suddenly you turn simple horizontal distance between you and any boat to your right into gain. The more sep, the more gain! Like this:
Imagine we both start at position 0. Expecting the leftie I go left, and you go right. In One Design boats we both reach positions 1 and are the same distance from the mark or as we say, on the same rung of the ladder. Now the lefties hits, and the you get lifted. Yea. I get knocked but tack, and we are now on the same heading. But the rungs shift as well, and now the horizontal component (factored by the degree of shift) of our separation is ALL GAIN. As we sail on the same heading towards positions 2 I'm crushing you because I'm now closer to the mark even though we sailed the same distance. And as long as the wind does not shift right I never have to give that back. Winning!
If you KNOW or predict (and in some placed you can predict this) that the wind is going to go say LEFT at noon, it makes sense to be left on the course. This leftie will knock you hard, but a tack and suddenly you turn simple horizontal distance between you and any boat to your right into gain. The more sep, the more gain! Like this:
Imagine we both start at position 0. Expecting the leftie I go left, and you go right. In One Design boats we both reach positions 1 and are the same distance from the mark or as we say, on the same rung of the ladder. Now the lefties hits, and the you get lifted. Yea. I get knocked but tack, and we are now on the same heading. But the rungs shift as well, and now the horizontal component (factored by the degree of shift) of our separation is ALL GAIN. As we sail on the same heading towards positions 2 I'm crushing you because I'm now closer to the mark even though we sailed the same distance. And as long as the wind does not shift right I never have to give that back. Winning!
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The idea is that if the shift is going to increase, then you want to already be on the side of the course to take advantage. For example, let's say that early in a leg you detect a 10 degree left shift, and it's forecast to turn 10 more. You want to get as far left as you can when you're only headed 10 degrees, so that you can enjoy the full 20 degree lift later and sail less distance. If you stayed in the middle of the course, you would later have to tack back and forth, splitting time between being headed and lifted. If the shift is persistent, but not expected to increase, then you're right, neither side is really favored.
It's pretty hard to say exactly when a shift will occur. In oscillating conditions there is some rhythm to it. But a persistent shift, while anticipated, doesn't occur on any particular time schedule. Many times around here it's a sea breeze filling in. It may or may not happen on a particular tack but if you think it's going to happen, that's the side of the course you want to be on. Soooo, you don't want to sail outside the lay lines for the current wind unless you can see the wind coming on the water and even then it's not a dead sure thing for a particular leg. You also have to cover your competition and not take a flyer. (I would have put more effort into this post but I accidentally hit the post button before I finished it).
We once experienced a dramatic example of the above scenario. We were getting clobbered by the faster boats that owed us time (PHRF). Big wind shift left, the side of the course that we were on. Tacked over immediately and fetched the mark (port side rounding) ahead of the other boats that were on the right and that were actually ahead of us at the time. I'll never forget that day! Remember the three elements of sailboat racing: Boat speed (money); tactics (knowledge/practice); and coursemanship (luck!).It works like this.
If you KNOW or predict (and in some placed you can predict this) that the wind is going to go say LEFT at noon, it makes sense to be left on the course. This leftie will knock you hard, but a tack and suddenly you turn simple horizontal distance between you and any boat to your right into gain. The more sep, the more gain! Like this:
Imagine we both start at position 0. Expecting the leftie I go left, and you go right. In One Design boats we both reach positions 1 and are the same distance from the mark or as we say, on the same rung of the ladder. Now the lefties hits, and the you get lifted. Yea. I get knocked but tack, and we are now on the same heading. But the rungs shift as well, and now the horizontal component (factored by the degree of shift) of our separation is ALL GAIN. As we sail on the same heading towards positions 2 I'm crushing you because I'm now closer to the mark even though we sailed the same distance. And as long as the wind does not shift right I never have to give that back. Winning!
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Having re-read it, I think maybe I wasn't clear with that point. If the shift hasn't hit yet, you want to get to the side of the course that will be favored, whether the shift will be persistent or continual. All I was trying to say was that after the shift hits, if it's not going to increase further, sailing the headed tack doesn't necessarily help.
Since you like reading up on the subject, Adam Cort has a very good description of this with a diagram in his book:
http://www.amazon.com/Getting-Started-Sailboat-Racing-Edition/dp/0071808264
(you can view the diagram on p47 of the "look inside" feature
)
http://www.amazon.com/Getting-Started-Sailboat-Racing-Edition/dp/0071808264
(you can view the diagram on p47 of the "look inside" feature
)