Sunday, July 9, 2017

Stand On or Give Way?

The (finally!) warmer temperatures mean it's getting more crowded on the water. Twice during the last week, someone who had been on a collision course with another windsurfer asked me "What should I do?". In both cases, the windsurfer who asked the question was on starboard, the other windsurfer on port. All windsurfers involved were experienced windsurfers. I'll describe the two incidents a bit further below, but first, let me answer the question.

If you are windsurfing and find yourself on a possible collision course with another windsurfer:

  1. Determine whether you are the "stand-on" windsurfer or the "give-way" windsurfer.
  2. If you are the "stand-on" windsurfer, keep your course
  3. If you are the "give-way" windsurfer, adjust your course so that you are not on a collision course anymore.
These rules are simple and clear. Note that there is no "right of way" here! The rules spell out clearly what each party must do. 

How do you determine if you are the "stand-on" or the "give-way" windsurfer? There are a few simple rules:
  • Opposite tacks: If two windsurfers are on opposite tacks, the starboard windsurfer is the "stand-on" windsurfer, and the port windsurfer is the "give-way" windsurfer.  Even simpler: if your right hand is closer to the mast, you "stand on". If your left hand is closer to the mast, you give way. (This assumes that you are sailing in a normal stance, not on the leeward side or back to the sail).
  • Passing: If you are overtaking another windsurfer, you "give-way".
  • Same tack: The windward (upwind) windsurfer is "give-way", the leeward (downwind) windsurfer is "hold-on".  In other words, the windsurfer who pinches higher against the wind has the right of way.
These rules are universal, but it is possible to find an occasional web page where they are explained in a confusing or incorrect manner. For a nice explanation with diagrams, check this "Rules of the Road for Sailboats" page. You can find the same rules at plenty of other places and web sites, for example the American Sailing Association, the Maritime College, boating instruction sites,  the US Sailing Windsurfing Instructor manual, or (in German) at the VDWS.

There are a few other rules and conventions worth noting. 
  • Sailboats (including windsurfers) are  usually "hold-on" when on a collision course with powerboats. Exceptions large boats like ferries and other commercial boats, and against boats with restricted to maneuver (for example in shipping channels). But note that different rules apply for powerboat vs. powerboat situations, and that many powerboat users are not aware that there are different rules for sailboats (and windsurfers)!
  • Stationary objects are by definition "hold-on", so sail around them. That includes windsurfer trying to waterstart.
  • It is a common courtesy to give beginners plenty of room, even if they are the "give-way" windsurfers. Similarly, planing windsurfers typically avoid windsurfers unable to plane. If courtesy is not your thing, you can consider the other windsurfer as "restricted in the ability to maneuver", which would make you the "give-way" vehicle.
  • If you are the "give-way" windsurfer, you need to adjust your course sufficiently to pass in a "safe distance" from the other windsurfer. That is generally at least a mast length away, but if you are passing in front of another windsurfer on the opposite tack, it should be substantially more. That applies even if you are a great windsurfer - even PWA Pros have spinouts and the occasional unexpected crash.
One thing that is often seen when windsurfers on opposing tacks are on a collision course is that the "hold-on" windsurfer changes the course slightly to point higher into the wind. That is usually a courtesy which allows the "give-way" windsurfer  to stay closer to his original course, without having to go too far downwind. 

So, now back to the two recent "Stand On or Give Way?" incidents. In the first one, I was on port tack, and another windsurfer was coming towards me on starboard tack. We were both planing, and at least 200 meter feet apart when I first saw him. It was clear that we needed to adjust course, but with plenty of time, I waited a couple of seconds to see if he'd pinch higher. He did not - instead, he signaled with his front hand to his windward side. I assumed that meant he planned to go there, and adjusted course downwind - only to discover that he did exactly the same thing! Apparently, his hand signal was supposed to mean "you go there". When we both saw that we had both adjust course downwind, he both re-adjusted upwind .. and were still on a collision course! After the two adjustments, we were now getting uncomfortably close, and both ended up in the water. I don't think we ever got within a board length of each other, and we were at least 50 meters apart after crashing, but it was still a bit scary, and neither of us liked it too much. We exchanged a few shouts on the water, including his question "What should I do?". I answered "keep your course if you are on starboard".  I think this is a very clear illustration why we have the "rules of the (liquid) road" - exactly to avoid this scenario.

The second case was a bit less dramatic, since both windsurfers were slogging, but ended up with a bit more drama. The windsurfer on starboard was a women in her 50s; the windsurfer on port a guy in his 50s who often behaves like a teenager. I did not see the incident. I was sitting on the beach next to friends, watching Nina have fun on my slalom gear, when Heidi came and asked "When I'm on starboard and someone comes at me on port, what should I do - hold my course, right?". We all confirmed that yes, that's what she should do. She had tried that, but ended up having to jump into the water to avoid a collision when the other windsurfer also held his course.

Heidi was clearly upset about the incident, and went to talk to the guy when he came of the water a while later. While we were on the beach discussing the issue, another female windsurfer also stated that he had used her as a jibe mark, and come uncomfortably close. There was a lot of nodding on the beach - most of us had had similar experiences. The guy in question apparently thinks that he is such a great windsurfer that it's perfectly safe to pass someone very closely. Well, most of the time he looks good, but he also has quite spectacular blowups almost every session - often, but not always, in jibes. Others on the beach shared other things that had bothered them about the same guy - things like peeing right in the parking lot, without even bothering to take a few steps in the woods, or dropping banana peels in the parking lot after eating bananas.

The talk happened too far away for us to hear, but it was clear that it did not go well - we could see the "I don't have time for this sh*t" gestures quite clearly. Heidi came back to report that that's what he had said, along with things like "you're just a bad sailor". That, now, pissed me off. I can understand if someone has misconceptions about the "rules of the road" - it happens. But being wrong, being arrogant about it, and being rude towards women - that's three strikes against you.

Up until then, I had thought to be somewhat friends with the guy - we even had invited him to share our house in Hatteras next year, despite some warnings from others who had shared a house with him this year. So I went to talk to him, and started by asking if he knew that the right-of-way rules apply regardless of windsurfing skills. He got upset right away  - "you were not there, you don't know what happened", so I asked him for his side of the story. He gave it, starting with "of course I knew she was on starboard", and "I was waiting for her to pick a course, either upwind or downwind". When I tried to point out that the port sailor (he) had to adjust course, I quickly became the target of his yells and curses, which included slurs about my nationality. At that point, it was rather obvious that this was not a guy I would want to share a house with for 2 weeks.

This is not really an isolated incident. Complaints about him sailing way too close to others are rather common, but since he is quite tall and likely to curse, most refrain from talking to him directly. He recently came back from a 2-week trip to Maui, and reported similar incidents there - again calling the other windsurfer(s) there that had complained to him "bad windsurfers" (in somewhat more colorful words).

The story ends on the parking lot a while later. I don't like to hold grudges, so when he derigged, I walked up to him and tried to make up. We actually should hands with "I got too excited" and "you know how I am" sentences exchanged, but could not quite refrain from talking about the incident. He stated that this was none of my business - which is where I disagreed. A better windsurfer bullying a women into the water, followed by being rude and arrogant to her, is not something that I will just let go. It was clear-cut before: he was wrong, and he was being an ass about it. But he made it even clearer what to think of him when he blamed the entire thing on Heidi having a bad day, and proceeded to call her "cranky old f*cker". Sorry, buddy - you are about as old as she is, and you certainly are the more cranky one here. And using terms like that about someone's friends - well, that's just sociopathic.

But on the bright side, we now have one more room in our house in Avon for the OBX Long Distance Race next April - 2 weeks sound front in one of the nicer houses there!

Tuesday, July 4, 2017

Destroyer

My windsurfing talent is limited. Sure, I may get planing 360s every now and then, but learning these moves took me many times longer than others - even other guys my age. Until recently, I thought that the one thing I am good at was sailing for a really long time. But now, I discovered that I have another talent: destroying windsurf gear.

Waves don't count - everyone can destroy windsurf gear in waves. No, I'm talking about just sailing back and forth, and soft little crashes. What - you don't believe me? Check out this picture of my Skate 110:
I am not talking about the big hole that exposes the styrofoam on the inside, either - I am talking about the air gap between the foam and the sandwich layer above it. The area had been soft for a while, but Hatteras board repair guru Donnie did not want to repair it - he said I should just keep surfing it. So I did, until I saw bubbles coming out of the foot screw holes. Then I got curious and looked inside.

On the cutout pieces, it's easy to see that the top layer of the styrofoam bubbles has been compressed. This is the area around the front foot straps, so the likely cause is slapping into the famous voodoo chop at Kalmus too many times. I sailed this board more than 250 sessions and more than 10,000 km (6,000 miles for non-metric thinkers, or the equivalent of 250 marathons for runners). That's not that many sessions for one board, and there is no visible fault in the construction - I obviously have destroyer talents! Since Donnie called the board a hopeless case, I'll keep using it to practice board repair skills. I ordered PVC foam and a vacuum pump to do a proper sandwich repair. However, the soft area has gotten rather large, so I'll also do some pour foam injection in the surrounding areas, and  I may have to also practice putting foot strap inserts in. I think this will keep me busy for a while!

But the board is not what convinced me that I must have extraordinary destructive talents - no, it's the sails. Just a week or so ago, I very gently fell into my favorite sail, a second-hand North Idol 5.6. Here's the result:
There's a huge rip going through the largest panel and into the lower batten pocket. The two pieces of sail repair tape from previous repairs are a sign that this panel was getting close to dying. However, the repair tape was on just one side of the sail, and the rip includes a previous largish rip. It's quite possible that this might not have happened if I had just remembered to also tape the other side of the sail when I got home... always tape both sides, and be generous with the repair tape!

On the bright side, this little mishap forced me to finally build a sail drying rack in our backyard that my lovely wife had requested, so that her precious sewing machine will not get exposed to salt from unwashed sails. That was today's little project:
Some of you will still doubt my destructive talents - perhaps rightfully so, since the sail was pre-damaged. But only yesterday, I succeeded in damaging another sail, with even less force! I fell on top of my sail at the end of a 360 try - very gently and softly, absolutely no force involved! But when I just touched the sail with my finger,  the monofilm split - a brand new 5 inch long tear. For once, this was not a  Karate move, more a gentle stroke. The sail was less than 2 years old, used fewer than 40 times, and looked like new .. well, until yesterday. Now that's destructive talent!

Thursday, June 22, 2017

Ducks Fly Fast

Ducks can fly - why can't I? It's not for lack of trying:
Maybe I need to flap harder? Or maybe I need to grow a pair .. of wings, that is. Probably won't happen.

The picture is from a session two days ago at Kalmus. After sailing back and forth for 9 hours the day before (I call that "distance sailing"), it was time to do something different - a bit of old school freestyle. I'll refrain from doing any freestyle as long as I have any excuse - "the water is cold" or "I did not sail much recently" being two of my favorites. So I still count the Duck Jibe as a freestyle trick. It's tricky to catch the sail after throwing it! Works better than trying to fly, though.

The crash in the picture above was harmless - perhaps all that flapping helped, after all. A little while later (and a little more tired), I had a better crash. If you've learned the Duck Jibe, maybe you remember the "Plank Walk": when your mast hits the water, and your gear suddenly stops, but you keep going ... straight off the nose of your board. That's pretty much what I did. Here's the GoPro footage:
That was fun! As a little bonus, I set my top speed of the day during my brief flight, according to my GPS:
I was three knots faster than in my second-fastest run! If you believe the GPS, that is. I really don't think that I was airborne for longer than 2 seconds - I would have flown about a 100 feet in that time! So let's look at the data more closely:

Here is the narrative to what happened:

  • I slowed down a bit during the sail duck, from 22 knots to 18.5 knots
  • When the mast hit the water, the board came to a sudden stop. Not so my body! Since my foot was still in the strap, the upper body did not just keep the speed, but actually accelerated from 18.5 to 26 knots within 0.4 seconds
  • I hit the water shortly thereafter. As soon as my hand was deeper than about 2-4 inches, the GPS watch lost reception, since water absorbs the GPS signal. We can see that point #24220 is not the expected 0.2 seconds after the previous point, but rather 1.6 seconds. So 1.4 seconds worth of data are missing.
  • GPS chips are made for cars, not for windsurfing. Cars often loose GPS reception, for example in tunnels or under bridges; but usually, they keep going at roughly the same speed and direction as before.  So the GPS chips go into "dead reckoning" mode, assuming that the "car" is still traveling at the same speed, and predicting the speed and new position.
Well, I may be many things, but a car I am not. I did stop when I hit the water. Speedsurfers traveling twice as fast as I did may bounce a few times before sinking, but I did not. So the GPS guessed wrong about how far and fast I traveled when I had no GPS reception. It corrected it's mistake very shortly thereafter: in point #24221, it adjusted the position by about 20 meters, roughly the same amount that it guessed wrong in the first place. The two points with large distances easy to see in the tracks:
For this particular file, only one of the three GPS speedsurfing programs gives the correct 2-second top speed. That is GPSResults, which refuses to use data points that have longer-than-expected time gaps. Both GPS Action Replay Pro and ka72.com use such data points, and therefore give an incorrect maximum 2-second speed that is "dead reckoning inflated" by about 3 knots.

Using accuracy estimates (SDoP filtering) to identify the "guessed wrong" data points could have worked, but would have required a threshold of 3.0 knots; the current threshold of 4.0 used by GPSResults would have let the bad points through. An "average SDoP" filter with a threshold of 1.5 that I had proposed earlier would have easily identified the bad points, and avoids the potential issues with invalidating larger stretches of data if single points are missing.

Now if I can only convince myself to duck jibe at the end of speed runs, maybe I'll finally get a 35 knot top speed...

Wednesday, June 21, 2017

Fun at Kalmus

It finally felt like summer today! Not that I'm complaining about windsurfing 5 out of the last 6 days, but fog in June just feels wrong. Today was sunny!!
After doing a bit of distance sailing two days ago (206 km, almost the distance of 5 marathons :-), I was a bit tired yesterday - but today was just perfect, with SSW wind and low tide. The 5.6 m freestyle sail felt so easy after 6 and 7 m freeride and 7.8 m slalom sails! Here's a short video from today: