Sunday, May 29, 2016

Twisted

After many days of good forecasts that did not happen, the wind finally came yesterday. It had been windy all night long, and meter readings early in the morning were around 25. When we got to the beach, they were 23. When we got onto the water at around 10 am, they dropped to 20. Still enough to have fun, after a bit of re-rigging and switching boards.

Martin was smarter. He was at the beach at 8 am. When I started re-learning my Carve 360s, he showed me how it's done, carving through one in style, with the sail all the way down to the water. Thanks, Marty! I got a few good ones right after that. Seeing how it's done helps. A lot.

Then I saw Marty go for loop crashes. I asked him about it, and he said he was working on the sail ride part. So I figured I'd show him a Gecko Loop. That's a non-planing trick where you can practice pushing yourself up on the boom to ride the sail. I had just learned it at the ABK camp in Hatteras a couple of weeks ago.

Unfortunately, I had forgotten that (a) I had learned the move in about 10-12 mph wind, and (b) when the wind picked up to 15-18, my tries got very bad, so that I quickly stopped. Here are a couple of pictures from these later tries:
In this try, I at least got the nose into the water, although not quite enough. Otherwise, the board is too flat - it should be tilted to the leeward edge is in the water, and the windward edge up. My back foot came out of the strap.
In this try, the board is even flatter - I did not even get the nose to go down. Fortunately, both of my feet got ripped out of the straps. This is somewhat similar to many bad loop tries I have done and seen where the timing is off.

When I tried to show Marty the Gecko Loop yesterday, I combined the worst elements of the two pictures above. I kept the board way to flat as in the second picture; but I also had my front foot nice and tight in the foot strap, so that it did not come out. That twisted the ankle in ways it was not supposed to be twisted. Quite a few tendons on the inside screamed at me in protest.

I took a little break to see if they would calm down, and then went back out for a trial run. But every little bump on the water sent little pain signals from my ankle, so I had to call it a day. Too bad, since the 25 mph wind returned a few hours later, and it was sunny and warm. But at least we were early enough to get a seat at one of our favorite places on Main Street, and were pleasantly surprised that the new cook at Gringo's can make some decent veggie tacos. So overall, I'll call the day a win - several good things (wind, sun, friends on the water, and decent food) beat the one bad thing. Seems I was lucky, anyway, and did not break or tear anything: a day later, I can walk (mostly) without pain, so this seems to be just a little strain that should go away in a few days. Maybe even in time for more wind on Tuesday...

Thursday, May 19, 2016

New Toy

The new toy:
The story:

It is dangerous to visit the windsurf stores here in Hatteras. They have way too many cool toys! Ocean Air is bad enough, but at least they have some kites to distract you. No such luck at Wind-NC. My advice: if Andy starts using his high-pressure sales tactics ("You might be interested in this..."), plug your ears, and run out of the store!

A couple of days ago, Nina needed a new outhaul line, so we stopped at Wind-NC. I should have known better to come in with her! Right away, Andy pointed out a little board he had lying on his big "Buy This" table: an Isonic W54 speedboard. I was not in the market for a speedboard. Sure, a few years ago, when Cesar planted the idea of speedsurfing in my head, I had bought an old F2 Missile. But its 62 liters were not quite enough for my 200 lb and the gusty and unreliable winds we typically get. It took me quite a few sessions before I managed to get a few decent runs on the Missile. So the Missile ended up mostly as Nina's speedboard, which she jumps on every once in a while.

I suspect that Andy reads this blog. How else can you explain that he mentioned that the Isonic has 72 liters? Ok, maybe I asked, but still! I definitely told him that I did not want to know the price. A new board would go for about $2500. This board had never been used, but it had spend several years in the corner of a warehouse, forgotten an neglected. Which meant that the price had dropped to about 1/3rd of the price of a new board. And bad Andy told me so. Hook, line, and sinker.

The final straw was that I had a little accident with our van just before we came to Hatteras. Someone had opened their car door all the way just as I was pulling into a gas station. His door was toast, my van had a little dent. The insurance decided he should have checked his mirrors before opening the door all the way, and sent me a check for the repair. The amount on the check was exactly the same as the price Andy quoted me for the board. How could I possibly ignore such a sign? So I bought it.

Even the wind gods cooperated, and I got to take it out yesterday. I got it to start right away, without first sinking to my hips into the water - nice! It cut through the chop nicely, and I felt right at home. I even managed to jibe it dry after just a couple of tries, and went for a few little speed runs. No great speed yet, that will require a bit more tuning and practice (and maybe less chop). I can't wait to sail the board on really flat water, though!

Wednesday, May 11, 2016

Blowup Sail

We're back in Hatteras. The wind has been on the lighter side, but that has not kept us from having tons of fun. I got to play around with a blowup windsurf rig in light wind, thanks to the friendly folks at Ocean Air. It's amazingly light, sets up in 2 minutes flat, and is tons of fun. Great for playing around in light wind on a hot summer day, or to get your kids to windsurf! Nina right away suggested that it's perfect for trying Caesar Finies' trademark move, the Hail Mary:
Praying that the rig will come back...
Even with a rig that weighs almost nothing, it's not an easy move. Perhaps I did not pray enough, or maybe I forgot Andy Brandt's advice that you have to look good waiting. Or maybe I just was too eager to get the rig back:
No, it did not

Tons of fun to be had with this rig. I got all of the ABK instructors to try it, too, and they came back with smiles on their faces. Many thanks to Martine, Brian, and Chris from Ocean Air to letting us try it!

Nina used the light wind times to work on pirouette tricks, looking good (as always):

Saturday, April 30, 2016

Apparent Wind Fun

Windsurfers know about apparent wind. I mean the physical concept, not the "apparently, there is no wind when I want to sail". Apparent wind is the combination of "true wind" (the wind we feel when standing still) and "induced wind" (the wind we feel when we stick the hand out of the car window). We can all add the direction vectors in our head, and end up with the strength and direction of the apparent wind, right?

Or so I thought. I learned about apparent wind a while back, when the original Windsurfer was a new board. Back then, we were typically going much slower than the wind. Let's look how the apparent wind changes for a windsurfer going at half of the true wind speed:
When our slow windsurfer is going upwind at an angle of 60 degrees to the wind, the apparent wind has an angle of about 45 degrees. When turning downwind to a 120 degree course, the apparent wind changes angles to about 90 degrees. That's a 45 degree change in apparent wind angle for a 60 degree change in course. Our sailor will have to open up his sail as he turns downwind almost to the same degree as he changes his course.

The curve above applied more than 30 years ago when I learned windsurfing, and it stuck with me. I never really considered how faster gear would change things until recently, when the apparent wind issue came up in our "International House of Speedsurfing" on Cape Hatteras. So I took a closer look, starting with the GPS tracks from Roo, the fastest sailor in the house. The program GPS Action Replay Pro lets you look at "Polar plots", which show the maximum speed at different sailing angles:
There's lots of interesting information in this plot: The maximum upwind angle was close to 60 degrees
  • The top speed was reached at an angle just below 120 degrees (it was quite choppy)
  • Maximum upwind speed was around 20 mph, maximum speed near 120 degrees was 34 mph.
The wind speeds that day were in the high 20s, with gusts just above 30, so Roo's top speed was just a tad faster than the wind speed. Let's look at the speed vs. board angle on a graph:

Board speed and apparent wind speed are show relative to to maximum wind speed. When going upwind at a 60º angle to the wind, the apparent wind was 40% higher than the true wind; when on a downwind speed run at a 120º angle, the apparent wind dropped to be roughly the same as the true wind. 

What I found somewhat surprising was the lowest line in the plot, which shows the apparent wind angle. It changed from just below 40º when going upwind to just below 60º when on a speed run. That's a change of just 20 degrees for a direction change of 60 degrees! Compared to the 45 degree change that we had seen for our slow windsurfer in the first diagram, that's a lot less. Our speedsurfer barely has to open up his sail by only 20 degrees when going from pinching hard upwind to full speed downwind!

Another thing I found surprising was that even when pinching upwind, the apparent wind angle was still about 40º. That's more than I would have thought. Over the years, I have had several experienced speedsurfer point out that windsurfers often tend to oversheet (once they got used to going fast). Roo also caught me oversheeting when he followed me to check my technique. He blamed the sail I was using, since it has a short boom and was developed for "light weights" (which I am not). But a wrong idea about what the apparent wind direction was probably also caused me to oversheet! 

I got a few of things to look out for when speedsurfing in the future: 
  • don't sheet in so much when going upwind or on a beam reach
  • don't open the sail too much in a sling shot
  • double-check your angles by comparing them to faster sailors, and/or by using GPSLogit and an Android phone to announce the actual speeds when sailing, and/or move your hands and harness lines closer together when speedsurfing to develop more sensitivity for the sail.
I suggest that my speedsurfing friends stop reading here. But anyone interested in loops should keep reading, because apparent wind strength and angles also play a role on speed loops. 

I admit that my interest in learning to loop had waned a little bit in the last couple of year, but the recent reminders that life can be short and come to a sudden, unexpected end have re-kindled my interest. So I started to think about loops again; to watch loop videos over and over; and to replay lectures about looping in my head.

One of the confusing things about looping is that spin loops can be initiated in many different ways. Some of the suggestions I have heard are:
  1. Jump high and sheet in hard!
  2. Whatever you do, try the first loops when going deep downwind!
  3. Stomp on the tail to practically stop the board, while moving the depowered sail to windward-forward!
  4. Take off at a slight upwind angle to get height, let the wind turn the nose of the board downwind a bit, then just hold on for the ride!
Some of these suggestions directly contradict others. But there is solid support for each of these suggestions. The last suggestion may be the one that is heard the least often, but it comes from a PWA pro who routinely throws some of the most beautiful loops ever seen, often on perfectly flat water. All the suggestions have helped many windsurfers to learn the loop. Nevertheless, some experienced teachers who have taught dozens of student to loop are convinced that other approaches to teaching are dangerous/no good/wrong. How confusing!

Well, apparent wind can also be very confusing to students. So there probably is a role for apparent wind in the loop! Let's see what we can find.

We will start with a simplified description of the loop: The loop is a catapult where the board is in the air and the feet are in the straps. 

We all catapulted when we learned to use the harness. Most of us did not like that, and quickly learned not to catapult. But we probably all remember that a sudden gust of wind can cause catapults. Sheeting in too quickly can have the same effect. Right away, this explains approach #1 to the loop: "Jump high and sheet in hard".  You'll get a lot more power in the sail and will get catapulted. Just make sure you are high enough in the air! A 10 ft wave on Maui to jump of works really well here. But for flat water loops, this approach can be downright dangerous.

Approach #2 ("do it downwind") is advocated by many windsurfers who have seen others get hurt by approach #1, or got hurt themselves. By going onto a deep downwind course before jumping, the chances of hitting your gear and getting hurt are drastically reduced. However, the downwind approach has one big problem: it is hard to jump when going deep downwind! Also, your apparent wind will be much less than the true wind, so there is just not enough wind to cause a catapult!

I know several very good windsurfers who tried to learn the loop with the downwind approach, but got nowhere. However, I also know several high-level freestylers who learned the loop with a variation of the downwind approach: they were working on Grubbies, and ended up looping instead. I have also seen "first Grubby" videos where the ending looked more like a loop than a proper Grubby, so the number of "Grubby loopers" is probably much higher.

One thing that you must do when learning the Grubby is to stick the nose of the board into the water to "create a rotation point", as the Tricktionary calls it. In a good Grubby, the board rotates 180 degrees, then slides backwards fully planing with you leaning forward on the board and backwinding the sail clew first to initiate another 180 degree rotation. But when learning the Grubby, there's a good chance that you kill most of the speed when sticking the nose into the water, with your board turned just a bit. As a result, your apparent wind increases to the true wind speed, and you get catapulted. Congratulation, you just landed your first loop!

The 3rd approach, "Stomp on the tail", is usually just a part of the entire instruction. I have seen some beautiful loops that clearly take this approach; but I have also seen beautiful loops that do not include tail stomps, even on flat water. This has confused me. What had me even more confused was a description "you stomp on the tail and stop the board, but your body keeps moving forward". That simply did not work for me. I can stomp on the tail to get a nice board wheelie, but all my weight must be on the back foot to do so, which means my body stops just as much as the board.

So let us look at what happens to the apparent wind if we go deep downwind, say to 150º off the wind, and stomp on the tail to kill speed. That's easy enough to do with plenty of apparent wind calculators on the web; I used this one. We'll assume that the true wind is 25 mph, and that our initial speed is 20 mph (typical for choppy conditions on freeride gear).
  • Initial apparent wind:
    12.6 mph, angle 97.5º
  • Apparent wind after slowing to 10 mph:
    17.1 mph, angle 133º
So the apparent wind has increased by 4.5 mph, and moved around by 35.5 degrees. If we had the sail luffed at the start, if will now be fully powered: we get catapulted! If we happen to the the board out of the water and pull up with the back foot, we'll get our first loop.

Now finally to the 4th approach: jump slightly upwind, move the rig towards the wind, let the nose turn downwind, and hold on! This loop advice is somewhat unusual, but it comes from Tonky Frans, not someone to take lightly when it comes to loops! Let's see what happens to the apparent wind here, again assuming 25 mph wind and 20 mph board speed:
  • Initial apparent wind:  29.6 mph, angle 45.3º
  • Apparent wind after the nose turns 20º downwind: 26.9 mph, angle 57.5º
This time, our apparent wind direction changed by only 12.2 degrees. But keep in mind that the nose of the board turned 20º downwind, so that the total angle change is actually 32.2 degrees! If the sail was luffed at the start, it is now nicely powered - without any active sheet-in! We're just holding on to the sail so that it does not get ripped out of our hands. Note that the apparent wind is much stronger than in our previous 150º downwind scenario (26.9 mph vs. 17.1 mph), meaning that the catapult will be more violent. That's good, because we have to turn the nose of the board an extra 50 degrees!

In all 4 approaches to the loop, we must get the sail suddenly loaded up, so that we get catapulted around. In the first approach, the load-up is initiated by actively sheeting in; in all the other approaches, the load-up is "automatic", caused by changes in the apparent wind. In reality, most loops will probably use a bit of a mix of the "active" and the "automatic" sheet-in, but at least in theory, either approach alone will work. Regardless how the sail is loaded up, the mast must pushed to foward-windward with an extended front arm: more to windward for a horizontal rotation, more to forward for a vertical rotation (I hope you jump high enough if you do it this way!). So, pick your approach and go looping!