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Before I stop the daily entries, I want to go over the windward leg wind shifts again.
Going up wind when the wind shifts, one tack moves closer to the windward mark (lifted) and the other moves further away (headed). The shortest and usually the fastest to the weather mark is to always sail the lifted tack.
So we try to sail the lifted tack until it becomes a headed tack. When one tack gets worse, the other gets better. So when your tack gets "headed" go to the other tack.
We try to stay out of the corners and delay going to the lay line, because then you can't take advantage of the changing tacks with wind shifts.
IF THE WIND DOESN'T SHIFT, all points on a line that is perpendicular to the wind direction are the same distance to weather mark. We call that line the Line of Equal Position (LEP).
You may want to draw that out on a piece of paper and measure the different ways to go.
When the wind does shift, the LEP shifts and the LEP of the boats toward the wind shift are now closer to the windward mark. Boats that were away from the change of direction now have further to go to the windward mark.
We want to "climb the Ladder" of LEPs toward the windward mark. The distance of boats apart on the LEP is called the "separation". The more the separation the more change with wind shift. The bigger the wind shift the more the change in position.
The further away from the wind direction change, the more you loose. A CHANGE OF 5 DEGREES IS 12 % OF THE SEPARATION. 10 DEGREES IS 25 % OF SEPARATION.
So sail low and fast toward the next expected wind shift. "Foot to the headers". You are increasing the separation and getting to the wind shift sooner.
If you are sailing a lift continue. "Stick with the lifts." You are "footing to the header".
"Cross them when you can." Often a lift lets you cross and it reduces the separation, when you are ahead.
"Don't let them cross you". If they are sailing a lift, then tack and lead them to the next shift.
If you are sailing a lift, sail low and fast to the next header. You will increase the separation on those following you. Helps you climb the Ladder.
If you decide for tactical reasons to continue a header, then pinch up (but stay fast) this reduces separation and helps you not loose as much on the ladder.
If you are ahead and "covering" by staying between your opponent and the next mark you are reducing the separation. If you are behind and trying to catch up you will be wanting to increase your separation to the next wind shift.
What about "the persistent" wind shift-- maybe tomorrow.
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2.2KW旋涡泵
3 years ago
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