Persistent Shifts for Dummies

By Doug

Roberto in Italy sent us this interesting chart. It shows four boats going upwind - the first 2 sail in a steady breeze while the other 2 sailing in a breeze that slowly shifts to the right:

• Black-left bangs the left and takes 16m 58s.
• Black-right bangs the right and takes the same, 16m 58s.
• Like most of us, red likes the lift but has to come into the mark on a big header, taking 17m 52s. This is 54 seconds more than the blacks because red is on the outside of a persistent shift.
• Green does something unusual - it sails on a header and then comes into the mark on a big lift, taking just 16m 9s. This is 49 seconds less than the blacks because green is on the inside of a persistent shift.

This is simple geometry - playing the shifts correctly means sailing a shorter distance which takes less time. But guessing when a shift is persistent is tricky - most people will stay on a lift like red and go the wrong way. It takes a lot of courage to recognize the shift is going to be persistent and take an early header like green to go the correct way.

The first time I learned about this was from Frank Bethwaite who was the Australian meteorologists at the 72 Olympics. Frank told me how amazing it was to watch Rodney Pattisson (GBR) who was the only sailor who recognized the long, persistent shifts at Kiel. Pattisson was the defending gold medalist and would start a leg going the wrong way on a header. This got him inside a persistent shift which only paid off at the top of the windward leg. Pattisson again won gold.

So Roberto's diagram is great because it quantifies the amount you can win or lose by not reading a persistent shift correctly. It's also great that most sailors don't sail at places like Kiel that have persistent shifts to worry about.

Actually, that's not true - we have persistent shifts all the time [Dummy alert - the following is simplified to make it a little easier to understand.]

The definition of a persistent shift is when the wind shifts one way and does not come back. In Roberto's diagram, the wind starts in a neutral position and goes right. If a shift cycle has 4 parts (go right, come back, go left, come back) and a leg takes less time to sail than a 1/4 of a shift cycle as shown in the diagram, then whatever the wind is doing is persistent. So it would make sense that the shorter the windward leg, the more likely the the shift will be a persistent shift. So the shorter the leg, the more you want to take an early header to get inside the shift.

So, how often does this happen? (Drumroll). Every windward leg! As we get closer to the windward mark, the remainder of the leg gets shorter and shorter. So, you guessed it, the top part of every leg has a persistent shift.

Some fun with numbers: Roberto's diagram has red losing 54 seconds and green gaining 49 seconds.

• If the wind completes one complete shift cycle (go right, go back, go left, go back) on a windward leg, then the top 1/4 of the leg has a persistent shift. This means that starting that part of the leg on a lift (red) means losing  54/4 or 13 seconds and sailing on the header (green) that gains 49/4 or 12 seconds - a total of 25 seconds!!
• If there are two complete shift cycles on the leg, green gains half of that, or 12 seconds on red.

How many times have we had good upwind speed only to round in traffic 12-25 seconds behind the leader who is in clean air?

Perhaps now we know why.

Sailing Angles Revisited

By Doug

I subscribe to the online Sail-World newsletter and it had a video of a race from the 18ft Skiff Nationals sailed on Sydney Harbor on January 19, 2014.

Most of the skiff videos focus on these flying machines screaming downwind and they're certainly fun to watch. This race was in a more gentle breeze and I watched it because it brought back great memories of living in Sydney in my 20's. If you're a sailor, there is no place on earth like Sydney Harbor.

The windward mark was tucked away in Watson's Bay so the conditions were quite tricky. Here are the two leaders who we'll call red and grey.

Red and grey are even.

And then something happened that was a repeat of what I saw with the excellent coverage at the London Olympics. I wrote a post about how it was amazing to watch some of the world's best sailors make what to me looked like a really basic mistake: if the boat you're trying to beat gets an inside lift, not tacking immediately is a mistake.

There were lots of comments - some agreeing but most disagreeing - including one from a Laser sailor who was actually competing (he disagreed). Pam even wrote another post that got even more comments that disagreed, none of which I found convincing.

So the inside skiff red gets the inside lift we were all commenting on.

Grey keeps going straight, red gets the inside lift.

I wrote that I would have tacked immediately for a bunch of reasons that included a header on one tack (relative to the other boat) is a lift on the other tack, needing to stay in contact with the other boat, etc.

But a lot of comments to my post said that grey should just keep going and things will even up, grey will 'foot to the next header,' tack, and regain any loss, etc.

Grey does not tack.

Grey either does not see this or decides to keep going.

The changes in these angles don't last long and sure enough, grey gets the same lift within a minute.

Now the wind direction is the same.

In my opinion, it's way too late for grey to tack. So what happens?

Grey tacks.

For me, the result is predictable. Grey hoping for a big header to catch red is rolling the dice with very poor odds. I did not see it in work at the Olympics and it certainly did not work here.

Red is waaaaay ahead.

As they approach the windward mark, red has a solid lead over grey.

Grey "puts it in the bank" by covering.

In my opinion, someone on grey should have kept track of red, seen the inside lift, and immediately called for a tack. Grey would have been a lot closer or even in the lead. But grey did not, and tacking a minute too late cost it a minute at the first mark.

No amount of boatspeed could have given red this lead so quickly. For me in these conditions, angles are better than boatspeed.

Pam:  Doug's recent detached retina and having oil still in his dominant eye has made his vision back to what it has been most of his life. As a result, I've noticed something interesting. Unlike the rest of us, he doesn't have the same variety of 3-D visual inputs. He operates in a stripped down 2-D world where he has developed strategies (rules of thumb) based upon very limited visual input. To him decisions are black and white and simple. To others, it might seems as if he's missing numerous nuances. I look at the above pictures and think about all the visual inputs that aren't captured that he isn't taking into consideration but whether it's live or a picture, his visual input is the same and his decisions are without doubt. I do have to wonder whether the 2-D simplicity has an advantage more often than not.  It's rather hard to test that but his observations are certainly worth noting. 

Sailing in the Middle of the Fleet

By Doug and Pam

Pam:  Recently, Doug and I crewed on a J/22 at circuit stop regatta. We'd start, couldn't hold our lane, slide down and have to tack away. If we had good boat speed (which we weren't sure of) we were still going to be sailing a longer distance since we couldn't point. To make matters worse, our crew work wasn't stellar. For me, it's a been there, done that ... often, spending a few brief moments with the fleet before waving good-bye and sailing by myself all day. For Doug (who was calling tactics) it was a foreign experience but that didn't stop him from finding ways to compensate for our shortcomings. It was an eye-opening experience to watch Doug emphasize tactics to keep us in the game. I'm always frustrated with all the books and clinics because it's all built on doing everything right.  I want to learn what to do to stay competitive when I do more wrong than right since that is my reality more often than not.  Seeing Doug put into that situation was fairly enlightening.  His post below only gives a few examples but really he was making lemonade out of lemons all weekend long ... except for when he fell out of the boat.  Even I know that rules 1, 2, and 3 on a keel boat is 'stay on the boat, stay on the boat, stay on the boat.'  But I did appreciate him making me feel good about myself for getting that part right.

Doug: Sailing without knowing how to tune a boat meant not-so-good boat speed which is, for me, a new experience. So crewing for a skipper new to the J/22 Texas circuit was a learning experience for all of us. It was different because sailing on a lake and being higher off the water gave us a better view of what the wind was doing.

Our starts were good so we had clear air, but we could not point upwind and had mixed spinnaker work downwind. We did manage to win one race, not using speed but tactics. Here are two things that made the difference.

As shown on the left, we're green in second place on the last run with our chute up. Red is a faster boat and is reeling us in. The natural instinct is green heading a little higher to keep out of red's wind shadow while trying to catch yellow. The problem is that red knows that it's faster and will still roll us, as shown in the middle picture. If we fight to protect against red, yellow simply jibes and gets away. Trying to hold our position with red will not work so a third place looked inevitable.

The solution was counterintuitive because it involved green going low instead of trying to defend against red. We waited for a little extra pressure to do this because bearing off always stretches the puff.

As soon as we were in red's wind shadow, we jibed away hoping that red would see yellow as the boat to beat. This worked, and they continued with yellow trying to defend and red trying to pass. They were unable to play the different pressure on the course, so when we converged at the bottom mark, we had taken the lead. Woohoooo!

Going into the final beat, yellow rounded the mark and tacked away to go left. Right looked better, so we continued with red chasing us, pointing higher as it had for the entire series. We knew that the next tack would win or lose the race. The breeze was quite shifty, so here were our options:

On the left, we're in the same breeze, which is what red wanted because of its better speed. If we get a slight lift for a few seconds and we tack, as shown in middle left, we're immediately on a starboard-tack knock which is bad. If we wait for a knock we can tack to get an immediate advantage from the better angle, as shown in the middle right. This works well in a Laser/Torch because you can tack on a small shift and then tack back again as needed. But in a J/22 with an inexperienced crew, this is risky because we were losing too much on our tacks and red was definitely gaining on us.

So we waited for when we were both knocked and were almost straight ahead, as shown on the right. Thankfully this happened just before the layline. We tacked, they followed, and we were just able to hold them off at the finish line. Our first Texas circuit bullet!! That night our skipper called any friend who would listen to tell them the good news.

For me, sailing without good boat speed was frustrating. For Pam, it was welcome-to-my-world. But I've always thought that you learn more in the middle of the fleet than at the front or the back. It was hard making mistakes knowing that catching smart, faster sailors would be almost impossible.  But getting near the leaders and occasionally having the chance to try different tactics to beat them made it an excellent learning experience and really fun weekend.

Frank Bethwaite, Brett Beyer and Doug

by Pam

AUS lifted inside, CYP ahead outside

Doug writes his posts primarily for me and nothing gets posted until I understand what he is saying and in his efforts to simplify things for me, he learns too.  I started this blog because I thought people might enjoy learning along with us.

Recently, Doug wrote Angles: Better Than Boatspeed which drew some comments from an Olympic sailor who did not agree.  Doug recently asked Brett Beyer offline about his thoughts on the post.  Brett didn’t agree with some aspects of Doug’s post and supplemented that there was another factor to consider, TIME (before laylines, knocks, etc.).  Brett would not have tacked if he were CYP.  He felt CYP's only option was to wait for the inside lift to fizzle and for the wind to shift back (knock) where CYP would then be able to tack into a more favorable position.  I must admit I didn’t totally understand his comments after working so hard to understand Doug’s post.  But since Doug’s time with Frank Bethwaite is still a significant influence on his sailing and since Brett knew and worked with Frank as well, and even wrote the chapter on Laser trim and handling in Frank’s last book, Fast Handling Techniques, which will be available later this year, I decided to go back to the source.

First, I pulled out Doug’s copy of Frank’s latest book, Higher Performance Sailing which directed me to chapters 10, 11, and 12 of High Performance Sailing with respect to persistent shifts.  And there, in Doug’s book with the inscription from Frank ‘With pleasant memories of shared dreams,’ I turned to a heavily highlighted Chapter 11 with terms like angles, percentage sailing, fleet sailing [round-the-buoy racing], minimum-time sailing [ocean racing], defensive sailing, etc.  Some familiar terms.  It’s official, Doug has reached that age where he’s learned so much, he’s forgotten from whom he learned it.  He couldn't recall Frank mentioning angles or percentage sailing.

On page 131 of HPS1, Frank explains that knowing when to tack is easy if your mind holds a correct image of the wind.  He describes the 'direct method' of accurately sensing the wind which he says is particularly effective in unsteady winds:

The rule is, ‘if a boat on the same tack, either ahead or behind, is pointing significantly higher than you are, or a boat on the other tack is pointing lower than expected, you must be in a header, so tack.’  The great advantage of this method is that the present pattern in your area is continuously revealed, and as well, the direction of the mean wind is constantly revealed and corrected.  Use this method, always, when you are in close company, and never forget to keep looking over your shoulder, at the boats behind, particularly when you are in the lead.

Hmmm… this sounds like the basis of Doug’s angles post.  When close to another boat, you are either lifted or headed relative to the other boat.  Doug has taken that to mean that when near another boat, he is judging his lifts and headers by the other boat and not the course or compass and he tacks accordingly.  While Brett acknowledged AUS was lifted and making a relative gain, he indicated CYP might also be lifted and tacking would negate that.  But Frank’s statement indicates that the angle to the other boat is telling you what the wind is in your area.  Now I’m confused.

But wait, it gets better.  Then we move on to additional statements in HPS1:

The technique above, slightly extended, is what fleet sailing is all about. 

When you are sailing in conditions in which there is no regular pattern this technique can be further extended to become ‘percentage sailing’.

If in these conditions you elect, instead to 'minimum-time' sail, and let the backs and veers run their course and tack on the nodes, you may well sail a shorter path to the mark and finish further ahead.  This is the technique of the ocean racer.  But if you are sailing around the buoys and do not have the luxury of being able to wait forever for the next back or veer, and the wind direction does not behave as you expect, you may well finish further behind.

Skill in percentage sailing the fleet is no defense against minimum-time sailing, split fleets, nor on downwind legs.

Percentage sailing will fail as soon as the wind shifts become regular.

And then, I was totally lost.  Doug’s concepts are simple for me to follow.  Brett, no doubt, is a better sailor and coach than Doug.  But, Brett is like a finely tuned racing machine.  Put him on a small, shifty lake like Doug normally sails on and he might never have room to get out of third gear.  So, maybe Doug knows a trick or two about light and shifty that Brett does not.  Wasn’t Weymouth on the shifty side?  Now Brett did say that he thought the angles were more significant in winds over 15 knots.  But, Doug thinks angles are more significant in light, shifty winds.  Frank did say “unsteady” winds but does that mean strong gusty winds or light shifty winds.  Somewhere between the three of them is the answer, but I’m not equipped to sort it out. My gut feeling is that 50% of the time Doug would be right and 50% of the time Brett would be right ... or maybe I'm 100% wrong.

Laser Cheat Sheet - Sailing Fast - Angles: Better than Boatspeed

By Doug

Laser Cheat Sheet. Half way up the first beat of the Laser medal race I made the comment that this was the "key moment in the race." Pavlos Kontides (CYP) was not going to beat Tom Slingsby (AUS) by the required 7 places to win the gold medal, so it was just a race to see who would beat who in front of the large crowd. The boats were even with CYP in the controlling right position (because tacking would have given him the right of way). And then this happened.

AUS got the dreaded (or wonderful) "inside lift" and the advantage immediately reversed so that when CYP tacked, AUS could cross and then tack on top of CYP. The race was over.

During the inside lift, AUS gained about one boat length on CYP every 5 seconds. No one has this speed advantage, not even Tom Slingsby, and is why I believe that sailing angles are more important than boat speed.

CYP did have a defense but did not use it - he could have immediately tacked and the inside lift advantage that AUS had would have been negated, plus CYP would have maintained his right-hand starboard tack control.

This happens time and time again with all sailors and was really obvious from the excellent aerial coverage at the Olympics. Here are some more examples from the women's match racing.

For me, the amazing thing about these photos is that no one on the outside boat is aware of what is going on. Absolutely amazing!

Now, I can understand how it's hard for a Laser sailor to keep looking around to spot this, but when there is a crew on board, then someone has to keep track of the other boat(s) to windward. Not doing so is a huge waste of boat speed, training, sponsorship, time away from family, and everything else that prepares Olympic athletes.

In each case, the outside boat must tack to negate this disadvantage, and if the inside boat also tacks, the inside advantage switches to the other boat for as long as this temporary breeze stays the same.

So, let's review: if someone told you how you could gain one boat length on your competition every five seconds, would you be interested? What could you possibly do to have such boat speed? The answer is never with boat speed – it’s just not possible in one-design classes. The answer is in something that few people understand – what I refer to as sailing angles.

Here, two boats are going to windward in a steady breeze. Neither has an advantage and either can go in any direction without gaining or losing.

Steady wind, and rare!

The good news is that in these conditions boat speed is the best way to gain, so you can go out and buy a new sail and polish your blades. The bad news is that the wind is never like this on the race course. So, before you spend any more money, spend some time understanding how these angles change.

In a race, one of two things happens. If the wind is spreading out and the boats are on starboard, the one on the left gains as shown by the color of the lines. All other things being equal, the one on the right must tack immediately and the one on the left must hope that he or she does not. If right delays tacking for just 5 seconds, it will lose 1 boat length. If the boats are on port, the one on the right gains and the one on the left must tack.

Wind is spreading out, common in puffs.

The key to sailing angles is sailing with your head out of the boat – looking around to watch the angles of the boats around you because they constantly change. This is important in match racing, and also how you can pick a specific person who you want to beat, something that I wrote about here. The best of the best have amazing boat speed, and this is one of the few  ways to beat them if that's your game plan:

Two campers are walking through the forest when they suddenly encounter a grizzly bear. The bear rears up on his hind legs and lets out a terrifying roar. Both campers are frozen in their tracks.

The first camper whispers, "I'm sure glad I wore my running shoes today."

"It doesn't matter what kind of shoes you're wearing, you're not gonna outrun that bear," replies the second.

"I don't have to outrun the bear, I just have to outrun you."

In sailing, I don’t have to hit every shift perfectly – if you're my target, I just have to beat you!

Sailing angles is how you can do this. If my game plan is beating a specific person, I’m much more interested in getting the angles right than where I am on the course or what my compass says. In fact, the very best sailors I get to compete against do not even own a compass. Sailing angles tell you what the wind is doing to your boat as well as everyone that you’re sailing with. No compass can do this.

Of course, the other thing that happens is the wind may be converging. For me, this does not make sense but it happens all the time and is what creates the inside lift. If the boats are on starboard, the one on the left loses as shown by the color of the lines. All other things being equal, the one on the left must tack. If the boats are on port, the one on the left gains and the one on the right must tack.

Wind is converging - strange, but happens all the time.

This is a scenario that is fairly common after rounding a leeward mark, where the inside boat gets the inside lift.

Red has his head inside the boat...

The lead boat has to keep looking over his or her shoulder and must tack if the inside boat is on a lift. In spite of this, very good sailors will focus on boat speed and not look around to see what’s really happening to their lead.

...and pays the price.

These diagrams show the boats side-by-side for illustration purposes, but sailing angles work for all boats at all times. In this next example, the boat in the lead on starboard should hope that the boat behind on the left does not tack. If it does, the lead boat should only cover with the understanding that it will lose until the angles improve.

Sailing angles work in any combination.

One way for the lead boat to ensure this is less of a factor is to sail directly to windward of the boat that it is targeting to ensure they both get the same wind with the understanding that the angles may sometimes be different as the boats sail into wind shifts. This favors the boat that is behind because it can force the lead boat to sail into headers for a few seconds per shift. The way that the lead boat defends against this is to tack on the shifts and hope that the boat behind does the same. The way that the boat behind defends against this is to sail into the header and hope to get some separation and its own angles.

Sailing angles are more important when the wind strength is less than 10 knots because the shifts and resulting angles are more pronounced.

To benefit from these sailing angles, you have to learn to tack quickly and to sail with your head out of the boat. The best way to do this is by sailing at night to enhance your feeling of the boat. A good daytime drill is to watch something upwind and be able to tack several times without taking your eyes off this object.

For me, there are three ways to sail upwind: by the course, by the wind patterns that you have, and by the competition. Sailing angles is purely by the competition. During any windward leg, the importance of these three strategies changes and it all boils down to one thing - when to tack. What works for me will be in another post. 

This is an update of original post on Butterfly Fleet 20 blog