Saturday, July 20, 2019

Jibe Practice for Foiling

We got our second foil three days ago: a Slingshot Infinity 84. I've foiled on it only for two short sessions, but so far, I love it. It gets me flying as quickly as Nina on the Infinity 76, with a sail that's just one sail size bigger. But more importantly, it can handle all my extra pounds much better than the 76 - no more spinouts and breaches! But my first attempts at foiled jibes on the i84 looked quite similar to those on the i76 - mostly crashes, with an occasional exception where I plane out of the jibe after the board touches down.

As new foilers, we are in a stage where we often hope that the wind does not pick up beyond 15-18 mph. This summer so far, the wind often has played along, but not yesterday - it picked up to the high 20s, gusting to 30. So it was time to take the old slapper out for a change - my white Skate 110 that I had repaired for foiling, since I had forgotten to put my new Skate into the van. Off to Egg Island we went. Nina tried her usual freestyle moves, but I was on a foil related mission: practice the sail first jibe!

After more than 20 AKB camps, I am a step jiber - when the sail moves, the feet switch (or at least they should). But for foiling jibes, there's plenty of advice to do a sail-first jibe (also called Power Jibe and Speed Jibe): flip the sail first, and the feet later. That's what the Horue jibing tutorial suggests, and Balz Muller says the same thing. I have tried enough step jibes on the foil to see that separating the sail and foot movements might be a good idea, but I almost never do sail-first jibes .. which means I did not really want to try them when flying. But being nicely powered on a 5.0 on perfectly flat water at Egg Island - there's no better training grounds!

So after a few regular jibes and a 360 try or two, it was sail-first jibe practice. I was surprised to find me planing out of them after just a few tries, and having tons of fun! I'm not good at multi-tasking, so flipping the sail first while maintaining the carve, and then switching the feet, seemed more natural to me than doing two things at once. When the wind picked up after a while, I ended up doing tacks on one side so that I'd be able to do some "slow speed runs" along the sandbank on the way back. Since I tack the foil much more than I usually tack my shortboards, my tacks had improved a bit - nice!

Here's the GPS tracks from the "forbidden jibe" session in the "kiddie pool" at Egg Island:
The jibe analysis with GPS Action Replay showed that this was one of my top-15 best jibing sessions (from more than 1300 sessions). Cool!

Hopefully, the wind will remain lighter today, so that I'll get a chance to try foiling sail-first jibes. For anyone who wants to foil at Kalmus, check these tracks from my last foil session there:

I was using a relatively short (71 cm) mast, but still ran aground about 800 feet from shore at low tide (0.2 ft). I tried walking into deeper water several times, but always made ground contact again when I tried to foil away. You can see the stones pretty well on the Google Earth image. I would have probably been fine another 100 or 200 feet further out, but the ground there is uneven, and my head was barely above water in the deeper spots. I ended up just body-dragging in.
So if you foil at Kalmus, check the tides, and make sure to walk out far enough at low tide! Once the tide level goes beyond 1-1.5 ft, even a 90 cm mast should be fine, though.

Saturday, July 13, 2019

Foil pictures

We had another nice foil session 2 days ago, and Eddie took some nice pictures. Here's Nina on the foil and Gonzalo on a longboard:
Nina was on a 5.2, Gonzalo on a race sail (8.5 or 9.5). He was one of the few windsurfers who was planing consistently - most guys on 7 m sails had a few good runs, but mostly slogged.

Fortunately for me, Nina was a bit overpowered on the 5.2, so she came in after a short session and let me have a turn. I started out on the 6.5:
I never like this sail very much, largely because it is low-end oriented, while all my older Gaastra Matrix sails were top-end oriented. However, it was great for foiling, powerful but stable. Cool!

The picture above shows my favorite "flight height" on the 60 cm mast: just barely above the water, so that the board just touches the waves a bit every now and then. One excuse for flying low is that I frequently get spinouts when most of the foil is out of the water. Those are usually not very dramatic, but often end up with the board slapping back down onto the water. The gently touches when flying low are much nicer, and loose a lot less speed. But perhaps it's really just my inner chicken asserting itself.

We took turns on the foil a couple of times, and I used the 5.2 for my second session. Here's another "flying low" picture:

Occasionally, I ended up foiling a bit higher, and I'm definitely making progress controlling the height.
I'm still amazed how much fun foiling is even at low speeds. My speeds typically were around 10-13 knots, with only rare spikes above 15 knots. That's about half of the speed of sailing on freeride or slalom gear! Here are the tracks for the day:
I had a few runs of 700-800 meters, pretty much the entire distance I foiled (limited by shallows on the left, and the stones from the old pier on the right). The longest "high foil" without touching the water was probably less than half of that distance. I made a few dry jibes, one of them close to planing, but did not foil through any. In contrast, Nina foiled through one of her jibes "by accident". I'm sure she'll have more of these "accidental foiled jibes" soon.

We have ordered a second foil, and it should arrive early next week. Maybe that will cause the strong summer winds to come back? We stayed with Slingshot because we really like the modular system, and the short 60 cm masts are great for low tide foiling. But we decided to get an Infinity 84 as the second foil (together with last year's front wing which Slingshot pretty much gives away for free), since I hope that it will push my almost 200 pounds up sooner. It may be a bit slower, but I don't think that's a bad thing anymore!

I almost ended up buying a Starboard GT-R foil. It would have been a few hundred dollars cheaper, and comes with a longer fuselage, which should make keeping a constant height much easier. One of the speedsurfers we met in Western Australia, Stroppo, regularly posts sessions with top speeds in the mid-20 knot range from the Starboard GT foil. Without any doubt, I'd be at least 5 knots slower (just like on the windsurf board), but that would still be plenty fast. However, I did not see any option to buy a shorter mast for the Starboard foil, which would have made foiling at Kalmus during low tide questionable, and foiling in the Hatteras sound impossible. So all I could do to imitate Stroppo was to try to look a bit like him:

During the session, wind averages from the iWindsurf meter at Kalmus were mostly 15 mph, with a few readings of 17; gusts were mostly in the 17-18 mph range, with a couple of 20 mph readings. I tried to plane with the 6.5 m sail on my Skate 110 a few times, but either the wind was too light, or I have forgotten how to sail a "slapper" in marginal conditions. When foiling, the 5.2 m sail was mostly ok, and only a bit smaller than I like in the lulls; the 6.5 was plenty big, and I could get up onto the foil pretty much anytime I liked, with (at most) minimal pumping. After 12 sessions on our foil, and about 20 foil sessions in total, foiling already had dropped the "good day" wind definition from 18-20 mph to 15 mph (and probably 13-15 mph). Sure, I could have planed with a 7.8 m sail on the 70 cm slalom board, but that would have been a lot more exercise and a lot less pure fun :-).

Wednesday, July 10, 2019

Light Wind Foiling

Yesterday's wind forecast was light, but it predicted a slight increase in the late afternoon. When the local wind meter readings increased to 11 mph, Nina suggested to try foiling with her 7.5 m longboard sail to find out how low she could go. Here's yesterday's wind graph:

By the time we were rigged and ready to go, meter readings were down to 8 mph. This may be foilable for PWA pros with huge sails and foil boards, but Nina only had 3 or 4 foil sessions on our gear, and fewer than 15 sessions overall. For more than an hour, her board stayed solidly in the water, except perhaps for a couple of seconds after vigorous pumping. But then, the wind picked up just a bit, and for 20 minutes or so, she was foiling most of the time, getting nice, long, controlled flights. When we got back home, we looked at the wind graph:

The highest wind average reading was 10 mph, gusting to 12, for about 10 minutes (9 knots gusting to 10.4). To plane on windsurfing gear, she usually needs at least 13 mph on the big slalom kit, and perhaps 18 for her freestyle gear.

Foiling in 10 mph with pretty limited experience is pretty impressive. The sail certainly helped - it's extremely light, has a deep profile and a tight leech, and soft cambers. But it was not rigged quite right, and Nina has not yet figured out how to pump it really well with the foil, so there's some room for improvement. We also just ordered a Slingshot Infinity 84 foil, which is larger and should lower the planing threshold a bit more. Hopefully, though, the larger foil will mostly help to get me going in similar light wind. Even on foils, bigger guys need a bit more power...

Tuesday, June 25, 2019

Silly Grin

I can't wipe the silly grin off my face. What a great day! It was raining. The wind meter readings were at 20 mph for about 20 minutes, and that was after I had left the water. I crashed a lot. My top speed was 17.3 knots, and my distance sailed 14.6 km - both numbers that usually would indicate a terrible day.

But I was on the foil. I had spend about 8 hours repairing my 71 cm slalom board that had a large-scale delamination on the bottom. Here's a picture of the zombie board in its current state:

Well, the little zombie works  a lot better than old Skate 110 or Nina's Bic Nova 170 I've tried before, so I've been foiling every time I got a chance in the last week, even when we got enough wind to plane on regular gear. Here are today's tracks:
It was low tide, so I stuck with the 60 cm mast, which probably limited my upwind angles (at least that's my excuse :-).  I spent a lot of time pinching upwind, but I was just barely powered most of the time. That limited the number of jibe attempts to less than a handful, but even in several of these attempts, I was amazed how long the board stayed on the foil and out of the water. Here's a video of one of the attempts:
I was so surprised to still be foiling that I just held on to the mast and waited for things to drop down...

I'm not sure what it is about foiling - the silent flying? The gently touches? The 100% concentration that forces you "into the zone"? The fun of learning something new, and be scared by going about half as fast as when windsurfing? Whatever it is, I love it! So big thanks to Andy Brandt and the ABK Boardsports crew for giving me lots of opportunities to try foiling; Slingshot for sponsoring ABK; and Britt Viehman from North Beach Windsurfing for advice and hooking us up with a great foil.

Monday, June 24, 2019

GPS Tracks in Google Earth

One of the features in GPS Speedreader I like is the ability to export GPS tracks to Google Earth to create pretty "crayon artwork", as Fangy call the images. Here's an example:
There are a few options to customize what you see:
For example, you can set a minimum speed, so that parts where you were going slow are all shown in the same color. A variety of different color schemes are also available. Here's the "high contrast" colors for the same track:

For the lower graph, I had selected the "Include time stamps and speeds" checkbox in the export options. This enables the time line in Google Earth, so you can "play" your tracks. It also write the doppler speed data to the exported file, which you can see as a graph at the bottom of the image (to see the graph, you have to right-click on the "Speed graphs" item in the side bar, and select "Show elevation profile"; then you'll have to click on the "Doppler speeds" in the graph panel). The speed graph also reacts to moving the mouse over it by showing an arrow with the speeds in the image above. You can also select regions in the graph to get average speeds for the region. Go ahead and play with it - downloads are free at

Another new feature in the just-released version 1.2.8 is support for .sbn files from Locosys GT-31 GPS devices.

Wednesday, June 19, 2019

That's Why We Use Freestyle Sails

This is why we use freestyle sails:
With freeride sails, the arms are too short for duck jibes! My large freestyle sails needs to be replaced (or have 5 (!) panels repaired), so I used a 6.0 freeride sail. I did move my hand back before the jibe, and my hands did crossover to get closer to the end of the boom:

Friday, May 31, 2019

GPS Speedreader

In recent years, I had gotten a bit frustrated with the existing GPS analysis software. For some of the GPS prototype testing, there were too many bugs that just made the life hard. Furthermore, the "older" software that was developed almost 20 years ago can be painfully slow when looking at new, higher-rate GPS data from the Locosys GW60 or the Motion GPS.

So I wrote my own, and I'm releasing it to the public today. It's free software, supplied without any warranties - but if you want to send me "beer money" to support the further development, that's great! There's a donation button on the  GPS Speedreader Help page for that. 

This post will show a few screen shots, and point out a few useful functions in GPS Speedreader. Here's the main window:
The session shown is my recent 12-hour, 306 km session where Nina grabbed the #1 spot in the GPSTC women's ranking for distance. It's a large file, and trying to see the 1-hour results in GPS Results on my Windows computer took more than 5 minutes. In GPS Speedreader, the file opens in less than half a minute, which includes calculating the results for all GPS Team Challenge categories.

The main window is divided in a left side that shows the GPS points on the top, and the category results on the bottom. The right side can show up to three graphs: tracks on top, doppler speeds in the middle, and error estimates on the bottom. Clicking anywhere will select the point or region; here, I have selected the top 2-second speed. You can zoom in using the mouse scroll wheel or trackpad gestures:
There are a few different dialogs where you can choose what you see, what your time zone is, and so on. Here are the general preferences:
GPS Speedreader was developed specifically with the GPS Team Challenge in mind, and with a lot of feedback from GPSTC advisors. It's pretty easy to post session results to the GPSTC - just select "View results in browser" from the "File" menu. This will open up a browser page with the results:
At the bottom of the results, there's a button. Click on it, and a session page on GPSTC will open, with all the numbers filled in for you. You just have to add a comment and press the "Post" button. 

GPS Speedreader does not have all the functions that other programs have. For example, background images are not supported, and there is no "Jibe analysis" like in GPS Action Replay Pro. I will probably add some more features over time, based on feedback on the Seabreeze GPS forum. But with summer starting here, I'll hopefully spend more time on the water soon!

A couple of things are unique to GPS Speedreader, though, and deserve mentioning. One is the "Compare files" function which I wrote to make comparing different GPS units easy. You can open two (or more) GPS files from the same session, and Speedreader will compare the results in all GPSTC categories. It will even compare the error ranges, and flag any discrepancies with a yellow, red, or orange background. If you want to have a close look at the data, you can pick which columns are shown in the data table:
But that may be more for geeks. Perhaps a thing that's more useful for many is that Speedreader supports opening files by drag and drop. On Mac and Windows, you can drop GPS files onto the application icon; on Mac, Windows, and Linux, you can drop files onto the main window.

To read more about GPS Speedreader, check the online help at To download the program and start playing with it, visit

Tuesday, May 21, 2019

Oops She Did It Again

Seven years ago, Nina briefly held the #1 spot in the women's distance ranking on the GPS Team Challenge - the unofficial women's distance world record for windsurfing. Her distance of 202.79 km was beaten a few month later by  speedfalconster, who sailed 207.55 km - barely 3 miles more. Her record latest until 2016, when the Australian speedsurfer Cheryl sailed 226 km. Cheryl sailed at Albany, a wonderfully flat spot that is in my top-3 list of the best windsurfing spots in the world.

Nina tried to get the record back a few months later during our regular spring trip to Hatteras. During the attempt, she also competed in the first Hatteras long distance race, where she won the Women's Open division. Alas, the waiting for the start of the two races ended up costing her the distance record when the wind died in the afternoon, just three kilometers shy of Cheryl's record. Another couple of months later, speedfalconster sailed 248 km to be back on top.

Nina had talked about another distance attempt a few times before, although she'd rather keep working on freestyle tricks (unlike me, she considers sailing back and forth for hours as "boring"). However, we never quite got the right conditions .. until this forecast came along:
Planing winds all day, and 14 hours between sunrise and sunset! I was definitely doing distance! So Nina decided to play along and forget about freestyle for a day.

The setup was good, but not quite perfect. One issue were the relatively weak winds in the morning; a bigger issue were the strong winds in the afternoon, and the southwesterly direction which means high water levels and more chop. Unlike earlier distance attempts, we did not have a house right on the Sound, so some of the daylight time would be wasted rigging and derigging. Perhaps even worse was that our fitness levels were still just mediocre, after having fought several severe colds since returning from Oz.

But when we got up at 5 am Monday morning, the local meters showed 18 mph wind - it was a go! We left the house just as the sun was coming up, and started sailing at 7 am. Believing that the predicted forecast would happen, we both rigged a bit small - 6.3 and 7.0. That meant some pumping  from time to time to get going, and slim chances to plane through jibes.

We sailed for about 5 hours, knocking off the first 150 km with relative ease. During lunch break, the wind dropped, shifted, and then picked up. Here's the wind graph from the "KHK Resort" meter for the day:
I downsized from 112/7.0 to 99/6.3 by grabbing Nina's gear. However, the wind in the high 20s meant lots of chop, and I found myself blowing jibes and not feeling comfortable anymore. What's the point of sailing for 12 hours if you're not having fun? I replaced the slalom board with my Tabou 3S96, which handles chops a lot better. I kept he cambered race sail (Loft RacingBlade 6.3), but the combo worked surprisingly well, and I enjoyed the next few hours of sailing. Nina switched to her freestyle gear - Fanatic Skate 86 and Idol 4.5, which she often sails in crazy conditions. We sailed these combos until we both had sailed about 250 km - Nina had her World Record back! But she was not yet tired and wanted to go for another 60 km. I hoped to add another 100 km, but by then, the wind and chop had increased to levels where our sails where just too big. Nina downsized her Idol to 4.0, and I switched to a 4.7 wave sail.

Then, things did not go quite as planned. An hour later, Nina had to stop because her hernia was acting up. Her total distance for the day was 277 km, about 30 km above the previous record. Nice!

I never got comfortable with the 4.7 wave sail, going between underpowered to overpowered in every run. Maybe the difference from the super-stable race sail was too much; maybe the chop had gotten too high; or maybe I was just getting tired, but I was getting slower, and spent a lot more energy than before. As the sun dipped lower on the horizon, I also saw a lot more wild life - including jumping, spear-like fish that are know to occasionally pierce windsurfers ankles. So I decided to stop an hour before the sun went down, so we'd be able to put all the gear back into the van while it was still light. Here are my GPS tracks for the day (click on the image for a larger version):
These are Nina's tracks:
Here's the women's ranking for distance on the GPS Team Challenge:
Today, the wind turned to NE, which means much shallower and flatter water. We went for a quick sail, and it was lovely - if only we would have had such flat water yesterday! But NE wind here rarely lasts all day - today, it lasted just a few hours. Maybe we have to go back to Australia for the next distance attempt :-).

Monday, May 13, 2019

Foiling in Hatteras

We had not planned to go to Hatteras this spring, but after the last cold water swim session, we made a last-minute decision to drive down for the ABK camp. We got a windy day on the Sunday before camp (3.4 for Nina, overpowered 5.0 for me) that showed us how out of shape we were. The camp was fun, as usual, although I spend most of the time trying to remember how to do things I had done before, with varying success. For me, the highlight of the ABK camp was the windsurf foiling on the last day. The wind increased to about 18 mph in the afternoon, which made getting onto the foil very easy - but controlling the power once up in the air was a very different story! I had only foiled a handful of times before, and I probably doubled my air time in this session. Fun!

Today was another day with warm SW winds. Meter readings were around 20 mph when we rigged, so I thought I'd have plenty of power on my 6.0/Skate 110/WeedDemon 29 combo. But of course, the wind dropped a couple of knots as we got out, and I only planed in the gusts. Perfect for foiling! The friendly ABK folks had left 4 foils out on the lawn at Barton's, and Tom and Brendon confirmed that it was ok to take my favorite combo out - a Slingshot Flyer with the 84 cm Infinity wing. Since the water depth here is limited, the mast was a bit shorter - 28 or 30 inches.

Once I reached the deep water and got on, the board wanted to get out of the water right away - it seemed the wind had increased by 5 knots! I made a bit of progress keeping the board flying a foot above the water, and had a bunch of fun crashes when the short periods of control ended. My favorite time was going upwind on the foil, but with the board just barely out of the water, so that the skinny nose of the flyer would still touch the chop. This ended up being my first foil session where I tried to sail at different angles to the wind. Upwind was reasonably easy, but any little bit of downwind angle made things very interesting and "lively". More fun crashes! At one point, I must have placed my foot a bit wrong, and the board/foil kept carving downwind until I noticed that I had gone past six o'clock. A quick sail flip, and I had completed my first jibe on a foil! Well, only the start was up on the foil, the end was with the board in the water, but it was fun. I even managed to do a second jibe later in the session, this one on purpose.

For this session, I wore a GPS, which showed a few interesting things:
The first thing to notice is the low speed. My fastest 2 second average was 13.7 knots - about 10 knots slower than an average session on my freestyle gear, and less than half of the speed of a light wind slalom session. But it sure felt plenty fast to me! Interestingly, my old Mistral Equipe raceboard probably would have reached slightly faster speeds with the same sail today (and 20 knots with a larger sail). I love sailing old longboards because the feeling of railing up on the daggerboard in intermediate winds is really cool. This is a bit similar to foiling - but the foil adds a completely new sensation with the foil push that's directed fully upward, without the heeling momentum from the daggerboard. Once the foil pushes the board completely out of the water and everything goes completely quiet, it's a feeling unlike any other on a windsurf board. When that happens, I need to concentrate 100% on keeping the board at an even flight height - I automatically get pushed into "the zone". Well, at least for a few seconds until everything comes down again, and I may end up getting thrown into the water.

The GPS tracks also show that many of the "foil runs" were very short. Perhaps 2 out of 3 times, I'd still be on the board after a touchdown, but the board had lost most of its speed. One out of three times was a dismount - sometimes getting thrown off by a bucking board, sometimes jumping off to make sure I'd stay clear of the foil after the exit. Fortunately, the water was warm, and the depth was perfect - deep enough for foiling, but shallow enough to stand.

Another interesting thing the tracks show is that my angles to or off the wind were not nearly as deep as I thought. In fact, the sailing was closer to typical shortboard sailing angles, which are mostly just going back and forth across the wind, than to raceboard tracks, which often include right angles. But then, I'm still a (slow-learning) beginner on the foil :-).

The longest steady run was about 750 meters over 2.5 minutes, with an average speed just above 10 knots. I probably was "semi-foiling" for the first half the run, with the foil pushing the board just almost out of the water. The second half of the run is at a lesser angle, so the board probably was completely above the water most of the time, with just a few gentle touch-downs every now and then. Amazing how much fun you can have at 10 knots, going slower than the wind speed! Big thanks to ABK Boardsports, Andy, Tom, Brendon, and Slingshot foils for making this possible.

Tuesday, April 30, 2019


Let me start by saying that there never was any real danger, and it all ended well. But for about 40 minute yesterday, there were some periods of doubt.

Yesterday's forecast called for 15 mph wind. With a little bit of thermals added to that, we were hoping for a nice mellow 20 mph, perfectly timed with low tide in the afternoon. The readings from the sensors around Buzzards Bay picked up shortly past lunch. Since southerlies don't always make it to Kalmus, we packed the big slalom gear and a long board, and off we went.

As we were rigging, the meter readings went up to 18, then to 20. Nina decided to do freestyle, and I started out on the 112 l slalom board with a 7.8 m sail. But the wind had already turned from "easy" SSW to "bumpy" WSW, and kept picking up. After fighting three colds in the last month, I did not feel 100%, and decided to switch to the easier longboard. That was plenty off fun. The daggerboard did not come out once, I had plenty of power to plane on the fin. Nina was hacking away on her freestyle, throwing Flaka tries as if it we mid-summer and the water was warm.

With the tide coming in, the wind picking up to the mid-20s, and the chop getting higher, I decided to seek flatter waters a mile upwind at the Kennedy Slicks. Getting there was easy, and I had a blast planing in the back footstraps on the ME2, with 10 feet of board high up in the air in front of me. But to play it safe, I stayed there just 20 minutes, and then decided to sail back. That's when it started to be really interesting, as the GPS tracks show:
See where the blue squiggly line starts? I had messed up a jibe on the outside, and the wind pulled the sail out of my hands when I was trying to waterstart. My first reaction was "great, now the sail is on the downwind side and I can just uphaul it" .. and then I realized that the boom had landed on the board, and the sail was mostly lying on top of the board, with just a little bit of the clew in the water. I realized that this could mean trouble, since the wind can push the board downwind really quickly that way. So I tried to swim toward the board, which was only perhaps 15 meters away, as fast as I could.

I am a decent swimmer and quite comfortable in the water. However, I was wearing a 5 mm wetsuit with a hooded neoprene vest on top; a seat harness; 5 mm boots; and open-palm mittens. With all this gear, the "fast" swimming was rather slow. After getting a bit fat over the last couple of months, breathing deeply in the tight suit plus vest plus harness was anything but easy - after a short swim, I was totally out of breath, but had made no visible progress towards the board. That's when things got a bit scary.  I had to think about the SUP paddler that they had pulled out of the ocean dead just a couple of days before. He probably died of a heart attack, and I started to wonder if my shortness of breath had any medical relevance. I had to concentrate on just getting some oxygen into my body for a few minutes, before trying a few more strokes towards the board. But it quickly became clear that the wind was carrying my gear away faster than I could swim. I was separated from my gear, in water that was about 10 C (50 F) cold, about a kilometer from shore. The chop out there was about 3-4 feet high, so the chances that anyone would see my head bobbing out there were just about zero. Swimming in all the gear was very slow, and did not seem to result in any progress towards the shore.   Swimming on my back seemed the best option, but after a couple of strokes, I'd end up with water in my face from a wave or wind-blown foam. So I ended up mostly treading water, without any clue if I was getting closer to shore. Nina had been the only other person out on the water earlier, but she had stopped by then. At times, I saw her standing on the shore looking out, perhaps searching for me, and I tried to wave both arms over my head - but it was clear that she did not see me.

After about half an hour in the water, I noticed several people standing on shore, looking out. Soon after that, I saw Nina sail again. Someone had spotted my board drifting towards land, so Nina went out to see if I was perhaps close to it. When she did not see me, she went back in, and someone on shore dialed 911. Nina went to grab the big slalom board, and then went to search for me. Around that time, I noticed the first blinking lights arriving at the parking lot - police, fire fighters, and an ambulance. The fire fighters also came with an inflatable boat that they soon launched.

Nina was the first one to reach me, and towed me towards shore, with me clinging to the back footstraps. The GPS tracks show that by then, I had drifted about 550 meters towards shore. Nina pulled me another 240 meters, and then I was able to reach the ground in about 4 feet of water. A minute later, the fire fighter's boat arrived, and they offered me a ride to shore, which I gladly accepted. Nina would have made it back to the launch on her own, but that was a dead downwind run, which was near-impossible with the gear she was on. Instead, she started to do a few "downwind tacks" on more moderate angles, falling at every turn. That made the fire fighters in the boat a bit nervous, so they picked her up, too. One of the fire fighters jumped out of the boat and walked her gear back.

Back on shore, I was walked to a waiting ambulance, where they checked my vital signs and listened to my lungs to see if I had gotten water in, which can cause "secondary drowning" a day or two later. My pulse was up to 140, which probably was mostly from shivering - the boat ride and walk on the beach had been a lot colder than the swimming! No big surprise for anyone who's ever done an ABK camp, and tried to keep his wetsuit on during the lunch break. The wind was still gusting above 30 mph, creating plenty of wind chill.

By then, the parking lot had filled up with police cars, fire fighter vans, and the ambulance. On the water, two more boats had arrived. The size of the effort was quite amazing! I am very grateful for all the efforts - big thanks to everyone involved!

There's a writeup about this with lots of pictures at
The pictures I find most striking are these two (click on the pictures for a larger version):

This is Nina going back out to search for me. I'm pretty sure I am somewhere in this picture, but it's impossible to see a swimmer's hear in this chop.

In this picture, you can see my head next to Nina - but the photographer has zoomed in quite a bit.

I just had to add this picture of two of the three fire fighters in the boat. Big, big thanks again!

In hindsight, I was never in much danger. Even though I made very slow progress swimming to shore, I would have reached shallow water within the next 30 minutes or so, since both wind and waves were pushing me towards shore. And while all the neoprene I had on made swimming hard, it kept me warm enough. Not that I did not really appreciate the hot shower when we got home!

Even though I sort of knew that I was not in real danger, and that I'd most likely be rescued before I drifted into shallow water, the incident was somewhat troubling.  I have been windsurfing for almost 40 years now, and needed rescuing twice in this time. I have sailed at least 1500 sessions, and this was the second time that I got separated from my gear. In addition, there were a few sessions where I got lucky when I lost a fin or crashed hard a few miles from shore, but was able to walk or sail back. Overall, I have been reasonably lucky - just in the past few months, I've read about several rather serious injuries that other windsurfers had when getting hit by boats, or just falling badly. Even something as simple as bad cramps while being separate from your gear a kilometer from shore would at the very least increase the panic factor. So in the future, planning for the worst-case scenario will definitely get more attention, especially during the colder months.

One of the things I might end up doing is carry smoke flares, like those required when racing in Australia. Another alternative is to always carry one of the phones I got for use with GPSLogit - even without activation, they can be used for emergency calls. However, I am not sure if I would have been able to place a phone call while swimming in 3-4 feet chop.

Another alternative for increased security is to use the Motion GPS, which has a built-in emergency function. The function is limited in that it requires another user with the same GPS to be within radio distance (about a mile or so). On the upside, it provides the coordinates, which can help with search efforts - and it is probably the best currently available GPS unit. I have thought about getting one, anyway, but could not really justify the expense. But for some peace of mind in problem situations, the price of about 260 Euros seems rather reasonable.

Sunday, April 7, 2019

Hour Analysis for GPSTC

When playing around with GPS prototypes, I developed my own analysis software to get around limitations and bugs of commonly used programs like GPS Action Replay (GPSAR; version 5.28) and GPSResults (version 6.170). Eventually, I shared my software ("GPS Speedreader") with a few similar-minded folks, so the question came up if Speedreader is accurate enough for posting to the GPS Team Challenge (GPSTC).

That lead to a validation study where I compared the results from more than 50 GPS files, most of them random downloads from This lead to a few interesting observations which might be of interest to anyone who posts sessions to GPSTC. Especially for the "1 hour" category, I discovered a few surprising things.

One of the tracks that stood out was the one you can download from

Here's what the speed track looks like if you open it in GPSResults:
The first surprise was that the number GPSResults gave for one hour was lower than the 9.082 knots that reported - only 8.466 knots! I checked in GPSAR, and it also reported 8.47 knots. Then I remembered that GPSResults used a minimum speed filter of 5 knots by default. When I disabled it by setting it to 0 knots, GPSResults reported a 1-hour speed of 9.015 knots - much closer to So the first big surprise was:
GPS Action Replay uses a 5 knot minimum speed filter for 1 hour!
I have always used GPSAR for analyzing my files, and never realized that. Even worse, unlike GPSResults, GPSAR does not let you disable the minimum speed setting.

There are different views of the 5-knot minimum filter in speedsurfing. When the older analysis programs were originally written almost 2 decades ago, the GPS Team Challenge did not yet exist. Speedsurfing was about top speed, 5x10 second averages, and 500 meters speed. Results for longer distances, longer times, and total distances were perhaps calculated, but mostly ignored. Furthermore, the GPS units available back then were quite prone to report speeds of 1-2 knots even when stationary. In this context, a 5-knot minimum speed filter makes sense.

But things have changed since then. Some clever Australians developed the GPS Team Challenge to get some team competition going. Having only the established disciplines 2 second, 5x10 seconds, and 500 meter disciplines would have given teams with spots like Sandy Point an unfair advantage, so they added disciplines that are better suited for other spots to even things out: alpha 500; the nautical mile (speed over 1852 meters); one hour average speed; and total distance. To win the monthly or yearly ranking, teams must post good results from all disciplines, since the overall score is computed from the ranking in each category. With 6 quite different categories and a requirement for posts from 2 sailors before it counts, it really takes a team to do well!

Besides the increased emphasis on total distance and long-distance speed on the GPSTC, another change happened over time: GPS units became more accurate. Modern GPS units like the Motion GPS rarely report speeds above 0.1 knots when stationary. Taken together, this makes a 5-knot minimum speed filter a very questionable thing indeed. A good one-hour results is above 20 knots, so it requires sailing about 40 kilometers. At most sailing areas, this requires about 20-40 jibes - sometimes even more. Sure, some of the best speedsailors in great conditions can plane through 40 jibes in a row and sail without crashing for an hour, but most of the time, one-hour runs will include jibes where we loose most speed, or periods of slogging in lulls. Why on earth should those times not count to the 1-hour average? In the example above, the slogging time was not very long, but still, including speeds below 5 knots increased the 1-hour average by more than 0.5 knots.

My conclusion from this is that I will not use GPSAR again for posting to GPSTC if there is even the slightest chance that my distance numbers matter for the monthly rankings.

But the story does not end here. In the track above, my Speedreader gave an even higher number. It selected a slightly different region, which upon close inspection made more sense. So the suspicion arose that there might be undiscovered bugs in the old code for 1-hour speed calculations. When I looked at more files, I found several examples that supported this conclusion, and even provided hints about why the older algorithms sometimes fail.

For an example, let's look at Boz' track from May 15, 2017 (downloadable at Here's the region GPSResults picked for the best hour:
Boz had his GPS set to a minimum speed of 5 knots, so a lot of points where the speed was lower are missing from the track. The reported 1-hour speed is 8.372 knots, corresponding to a travel distance of 15.5 km. But GPS Speedreader gave a higher speed:
By selecting an hour about 10 minutes further back, Speedreader found a region with a travel distance of 17.3 km - about one nautical mile longer! Accordingly, the 1-hour speed is about one knot higher.

Theoretically, this could be some kind of bug in Speedreader, so let's look at this region in GPSAR. First, here is what GPSAR selected as the fastest 1 hour:
 This is the roughly the same region that GPSResults picked. But is that really the region where we travel the most distance in one hour? Let's look at the track points table in GPSAR for the first valid point in the region Speedreader picked:
And for the last point:

The difference in accumulated distance is about 17.7 km, traveled in less than one hour. So this region should have been picked for the best hour in GPSAR, too!

So why did GPSResults and GPSAR (and, most likely, pick the wrong regions? Simple answer - because the 1-hour algorithms were never designed for tracks with a large number of missing points. The typical search algorithm will start at every valid point, find the point one hour after it, and calculate the speed for this region. But look at the graph from Speedreader: the best hour starts in the middle of the missing points! So the programs never even consider that an hour could start there. They can handle missing regions at the end of a one-hour run, but not at the start!

So why does Speedreader find this region? Mostly by luck! Speedreader was designed originally for comparing two GPS files. But if files sometimes miss some points, that can make the comparison complicated, so Speedreader simply fills in missing areas with points of speed 0. That allows it to consider every "missing point" in large missing regions as a possible start, and therefore succeeds in finding the best hour in this example.

There are other ways to also find the best hour, without having to add the interpolated point. Perhaps the easiest is to also look for hours going backwards - from every valid end point, calculate the average 1 hour speed towards the front of the file. This would find the best one hour in this example.

But at least until other GPS analysis software has incorporated such a fix, the best thing to do it to set the minimum logging speed to zero. All the examples of incorrect 1-hour results I have found were from files with a non-zero logging speed. Note that a minimum speed above zero can also affect the nautical mile or alpha results: if those happen to have a point with a speed below the threshold, the run may not be counted due to the missing point.

Saturday, March 16, 2019

Movie: Into The Weed

Sometimes, it takes a big trip to learn to appreciate new things.

Sunday, March 3, 2019

Lake George

One of the things that had drawn me to Australia were windsurfing videos from Lake George in South Australia. In a good year, you can windsurf Lake George on glassy water in 25 knots, without any chop. So we ended our trip with a couple of weeks at Lake George.

But things did not seem to work out quite as planned. Before we even got there, we saw multiple reports that the water levels were much higher than ideal. In good years, the chop-killing weed reaches the surface; but in February 2019, the weed was covered with about 2 feet of water.

The trip from the Perth region in Western Australia to Beachport in South Australia took us a few days (partly because we did not drive at night, when there is a high chance that you hit a kangaroo). When we arrived in the afternoon, we drove to the launch light away, and it looked beautiful - very flat, with about 20 mph of wind. Unfortunately, we did not get to sail that day. The next day was quite windy - but cold! Temperatures dropped to about 14 C (57 F), and it rained a bit at times. Our summer wetsuits proved to be a bit too light for the wind, which also was very gusty. We started to question how smart is was to leave Western Australia for that. The last spot we had visited, Albany, had been fantastic, and rewarded us with several personal bests each; but we only managed low 30-knot numbers this day. Frustration again, similar to the first really day at Fangy Land: the better windsurfers got speeds in the high 30s, and one or two even got 40-knot top speeds.

It got a bit warmer the next couple of days, but the wind remained light. We got to meet a number of Australian speedsurfers in the local pub and on the beach, including the holder of the official 24-hour world record, "Kato". Kato saved me from rigging in dying winds one day by letting me use his gear in the last few gusts, and let me use his Mistral IMCO longboard another day where the wind again was light and gusty. In many parts of the lake, the weed was too close to the surface to fully extend the daggerboard, but I still had a blast, even though I had to use the 6.3 m sail, since Nina was using the 7.0 on the big slalom board. But another advantage of the light wind was that I was able to get some drone footage, without having to worry about the drone getting blown away. Here's some footage of Nina on the 7.0/112 l combo:

Unfortunately, our friends Mike and Dot had to leave a few days later, and the three "Teletubby Brokeback Speedsurfers" from Mandurah who shared the cabin next to ours also left when the wind forecast was very poor for several days in a row. That meant that we lost some of the gear we had used (or hoped to use) in very light or very strong winds: Mike's 4.4 m sail and 39 cm speed board for Nina, and the 112 l slalom board (a loaner from Jonski - thanks again!). On the bright side, it prompted us to switch to a lovely AirBnb place with lots of space, a super-friendly host, free loaner bicycles, and frequent sightings of kangaroos right next to our place - nice!

The wind finally returned for the last two days of our stay. Here is a GoPro short video that I took at the beginning of the first day:

This was in about 5 knots more wind than in the first video above, about 18 knots. At almost all windsurf spots, 5 knots more wind would have also created more chop - but not so here! The heavy weed limits how big the chop gets, and the water was very smooth. The wind picked up during the day, probably reaching averages near 25 knots before I stopped sailing, but the chop never seemed to get any bigger. Sweet! Well, I should be more specific: the chop did not get noticeably bigger in the middle lake, which is shallow and weedy. We actually ended up sailing a bit in the big lake, which is deeper at parts, and has substantially less weed; in the deeper parts, the chop is more comparable to the Hatteras Sound (think of the area near Avon, in the middle of the long distance race).

Here are my GPS tracks for the day (click on the image to see a larger version):
We started at the bottom-left corner, from a launch known as "5 Miles". The mast mount video above was taken right in front of the launch. We then sailed up to "The Spit" - a sand spit that separates the middle lake from the big lake above it. The sand bar is just perhaps 10 meters wide, and a meter tall, so the water behind it is perfect for speed sailing. I spent most of the day on the Falcon 89, and got a top speed of 34.8 knots on it - the fastest I had ever been on a slalom board. After a couple of hours, when Nina took a break, I got six runs on the Isonic W54 speedboard in. Three of the runs were above 35 knots, and the fastest had a 2-second top speed of 37.09 knots (68.7 km/h) - that's the second-fastest I have ever sailed, and only the second time I have sailed faster than 35 knots.

After hearing about my speeds, Nina wanted a few more runs on the Isonic. I ended up getting quite cold waiting for her, so I started to sail back to the launch, which was about 1.5 miles upwind. Since the wind kept picking up, getting back was reasonably easy and quick. I later looked at the GPS tracks of Hardie, who did more than 40 knots that day, and they confirmed that the wind picked up a few knots during and after our trip back. However, we were quite tired by the time we sailed back, and not quite sure how easy it would be to sail back upwind. I was definitely happy to have a few reserved left to manage the 7.0 m sail in gusts that must have been above 30 knots!

For the next day, the wind forecast had predicted a few more knots of wind, so we decided to drive out to the spit. It's just a 5 kilometer (3 mile) drive from the 5 Mile launch - but the road is "very interesting", with sand, huge potholes, and rocky areas. It took us 30 minutes to drive the last 3 miles!  But at least we now had the option to change gear whenever we felt like it.

I went out first on the 7.0/89 combo, and quickly got a top speed of 34.5 knots. The wind seemed to be picking up, and both local expertise and the forecast predicted an increase, to I quickly rigged down to the 6.3. Unfortunately, the wind had other plans, and stayed perhaps 5 knots weaker than the day before, so I had a hard time even getting 34 knots again. But the water in front of the speed (below in the image above) was just a few inches above the weeds - tons of fun to go back and forth in! I tried to improve my 1 hour personal best, but had a few problems jibing, so ended up 0.8 knots short of my PB. Nevertheless, these three hours of going fast for a couple of kilometers each run in "chop" than ranged from about 1 inch to maybe 3-4 inches were some of the best hours I even spend on a windsurf board. The SSE-SE wind was a lot steadier than the gusty SW-WSW wind we had on our first day of sailing at Lake George! Even Nina, who usually gets bored going in a straight line after a minute or two, sailed back and forth with a big grin on her face for hours, and ended up improving her 1 hour PB without really trying. After these two days, we both understood why windsurfers from all over Australia come to Lake George!

Wednesday, February 27, 2019

The Car

Our trip to Oz is almost over. Yesterday, we said goodbye to the Falcon:
We bought the Ford Falcon station wagon a few days after we arrived. On the inside, the lining under the roof had been removed, so it did not look pretty. But it drove well, and had only 220 thousand kilometers - about 100-200K less than similar 15-year old cars.

It has had a few little problems. The day after we bought it, we discovered that one of the doors in the back could not be locked. Back to the mechanic who sold the car. He "fixed" it - it was now permanently closed, and could not be opened anymore. Much better! The back seats were folded down to accommodate our windsurfing gear, anyway.

A day later, we discovered that the door on the back also did not close. Not feeling too smart now, but finally understanding why there were so many disconnected cables in the back, we almost drove back to the mechanic again. But before we had a chance, our windsurfing friend Mike fixed it for us.

The only other issue was a flat tire a few weeks later. A couple of tires were now close to the legal limit, and he were planning to drive through the Nullabor, where there are many hundred kilometers between towns. So we replaced all tires for AUD $360, hoping that the new tires would make it easier to sell the car.

The biggest bummer about buying a car was that we left Lake George a few days earlier than absolutely necessary, so that we'd have a few days in Melbourne to sell the car. Of course, conditions were perfect a couple of days later, and some guys got their magic 40 knots for the first time. At least one of them improved their previous best by about 4 knots. Who knows what we could have done? Maybe next time..

We ended up selling the car to a guy from Canada who is here for a year. It helped that the car was registered in Western Australia: transferring the registration can be done by mail; no safety inspection is required; and the registration (which includes insurance) can be extended easily over the internet, which he did right away. We got exactly the same amount we had paid for the car, so it cost us less than $600 for the registration and the new tires - a lot cheaper than any rental would have been! Perhaps we got lucky because nothing major broke, but the car was made to be used as a taxi, and it's supposedly good for a million kilometers. Seeing that there are lots of these Falcons around with more than 400K kilometers, that probably true.

How was Lake George, you wonder? We'll fantastic .. but that's a different post.

Monday, February 4, 2019

With A Little Help

Two days ago was our last day in Mandurah - and it was windy! Mike did not believe my prediction of wind between 25 and 30 knots, so we went to Fangyland instead of Liptons. Fine by me - I love Fangy's Weed Farm!

We arrived to plenty of white caps, and a big crew on the beach, getting ready to go out. It was still cloudy, but the end of the clouds was in sight, and several sailors predicted that the wind would pick up once the clouds were gone .. which it did. I got out just before that happened, so I had some time to get dialed in on the Falcon 89 with the Racing Blade 6.3. Nina went out on the RB 5.0 with Mikes 39 cm "wide" speed board. Yes, all of 39 centimeters. She had to suffer through plenty of comments on the board - one guy remarked that she should have a second board, one for each foot. He had a point - the board looked more like a water ski than a windsurf board! Since she does not waterski, it took her quite a while to get comfortable on the board. Once it became clear she'd keep using it, I switched down to our Isonic W54 speed board.

By then, the wind was quite strong. Meter readings on shore later showed 25 knots with gusts to 32, but it may have been a bit higher on the speed strip. Everyone was taking breaks at the end of the runs, which were a bit longer than a mile - almost 2 kilometers. That was rather nice - lots of tips on where the flattest water was, how to tune the gear, and so on were exchanged. One of the local legends, Stroppo, first showed Nina the run below the weed banks where the flattest water could be found, and then made sure I also knew about it. Very nice!

I was using GPSLogit with bluetooth headphones, and had heard "35" several times during runs. The GPS watch confirmed that I had set a new personal best, and finally (!!) broken the 35-knot barrier. That helped me relax a bit. Or perhaps the wind just picked up. Whatever it was, I saw a 37.6 on the dial after the next run. That was 2.8 knots faster than my old personal best - a huge jump! I had also tried to copy Stroppo's approach to a nautical mile run, and had improved my PB for the "nauti" (often spelled "naughty") my 2 knots. Sweet! I was getting a bit tired, and we had a big drive planned for the next day, so I decided to call it a day.

Nina said she wanted to stay out, since she was finally getting comfortable on the tiny speedboard. When she came in a while later, she was glowing - she had just improved her personal best by more than 3 knots, to 35.78 knots! At the end of the day, we each had improved our personal bests in three categories - top speed (2 seconds), 5 x 10 seconds, and nautical mile. Sweet, sweet, sweet!

It was time to say good bye to the local speedsurfers we had gotten to know during our stay, an extra-ordinarily nice bunch of people. Quite a few of them had also set new personal bests - the two teams I mentioned in my last post, the Mandurah Mob and the Pinnaroos, each set a total of 9 PBs that day. What a day!

The big question is: what made us (and others) go so much faster? Clearly, the conditions played a big role: strong winds and very flat water. But we had had quite similar conditions before at exactly the same spot, with no or just marginal improvements. But this time around, the wind direction was different, so the runs in smooth water were more than twice as long. Together with steady winds, this gave us plenty of time to get used to the conditions and to the higher speeds that were possible.

Just as important, though, was the company of better speedsurfers. Their friendly and freely given advice (both during the session and in and after previous sessions) was super-helpful. Mike's 39 cm speed board was essential - not only did it enable it Nina to go wicked fast, but it also freed our speedboard for my use (and the W54 was much more appropriate for the conditions than the slalom board!). So a BIG thanks to Mike, Stroppo, Ross, and all the others who have helped us!

Yesterday, we drove to Margaret River, and arrived just in time to witness a Severne team photoshoot, complete with helicopters and mast-high wave. The show was amazing, with super-high back loops, one-handed aerials, wave 360s, and more. I went to thank multiple world wave champion Philip Köster after the session, and got to shake his hand - cool!!!

Today, we drove on to Albany, another famous speed spot. After stops for a walk through giant tree tops and at the "Elephant Rocks", one of the most beautiful coasts I have ever seen, we arrived a bit late at our bay-front cottage, but I managed to squeeze a session on the big gear (112/7.0) in. This is another perfect spot, with weeds sticking out of the water that keep it really flat and create a "jibing heaven. Despite only about 16 knots of wind and a top speed below 29 knots, I managed to get an alpha 500 of 23 knots - just 1/3rd of a knot below my personal best! Sooo much fun! And there're more wind in the forecast for tomorrow :-).

Between all the fun, I somehow found the time to check our individual rankings on the GPS Team Challenge. Here's what the top 10 for the speedsurfers in USA teams currently looks like:
Somewhat magically, I already advanced to third place, within 2 points of the second place - and we still have a couple of weeks at super-flat, super-fast Lake George coming up! Nina is currently on the 8th place, ahead of 30 guys - the girl is fast!

Wednesday, January 30, 2019

Battle For First Place

Fangy's Weed Farm looked peaceful today:
Yesterday? A very different story! In the monthly rankings on the GPS Team Challenge, two local teams were tied for first place: the Mandurah Mob and the Pinnaroos. It was time for a showdown!

Our host Mike, team captain of the Mobsters, barely waited for the first white caps to show up on the ocean to head out to Coodanup, where Fangy's Weed Farm creates some of the flattest water I have ever seen. In 2017, this was perhaps the secret weapon that brought the Mobsters the victory in the battle for first place in Australia - but since then, large groups of "pesky Pinnas" have invade the weed farm on a regular basis. Yesterday was another invasion day - 6 Pinnas showed up hoping the good forecast would come true, matching the number of Mobsters.

But the Mobsters had a good plan: go for distance, and perhaps improve the 1-hours speeds at the same time. I tried to help with the only thing I could think off: distract the Pinnaroos' team captain by offering her jibe advice, and even showing her a bit of sail chi on shore. This kept her too busy to advice her team mates on strategy - although in all fairness, it might have been too late by then, since Mike and his team mate Slugger already had been on the water for a couple of hours.

My little sail chi distraction did serve a second purpose: it made me hit the water just as the wind picked up, so I was very nicely powered on my 7.0/112 combo right away. I had planned on giving some more jibe advice on the water, but had way too much fun on the flat water to stop. The wind direction (SSW) was perfect in that it created really nice long runs, so I changed my plans and went for 1-hour speed instead. Whoever invented this category for the GPS Team Challenge must love going back and forth as much as I. The "short" runs were about 1.5 km long, mostly right at the edge of the weed, but sometimes just below weed beds in "chitter-chatter" water, and a few times straight through the middle of the weed (made possible by the incredible Fangy Fins).

All the time, I saw Mike and Slugger go back and forth like the real speed machines they are. A few times, I followed Mike around, but I had to really concentrate on speed, or he would have left me behind very quickly. Impressive!

At the end of the day, the deed was done: the Mobsters had jumped to second place in the distance ranking for the month, and also improved their ranking in the 1 hour category, jumping way ahead of the pesky Pinna invaders:
I had a blast watching the action from the water, and got inspired to try harder. This time around, I sailed in my favorite conditions: lighter wind (perhaps 22 knots) and big gear (7.0/112/22). Jibing was just too much fun, and the wind direction also had the alpha markers in a perfect position, so it was no big surprise that Nina and I both improved our personal bests in the alpha 500 category a bit. When I looked at the postings from the Pinnas and the Mobsters, however, I was in for another surprise: of the 14 windsurfers from the two teams and the "USA" team, I ended up with the fastest 1-hour and 2-second numbers! The hour was perhaps not surprising, since that's perhaps my best category; but the 2-second "top speed" category was a big surprise. I'll blame it on the new "Stroppo's Curves" approach, which I tried many times in the middle of the runs. Big thanks, Stroppo!
Here's a table with the results from the 14 sailors from the 3 teams at Coodanup yesterday, with rankings in each category and an overall ranking (the sum of all categories):
Mark ended up in first place - well deserved, he set three personal bests that day! I ended up in second place overall, which makes me very happy. In conditions I'm familiar with, I'm not half bad after all! It's good that I did not get first place overall - that would have inflated my ego way too much, probably enough to have my head explode. Chances are I would not mind much since I'd die in a state of happiness, but I'd be really sorry for Mike and Dot having to clean up the mess!

Sunday, January 27, 2019

40 Knots Or Not

It was wicked windy a few days ago when a big storm system pulled through. We followed the local experts who drove an hour south to Australind, looking for the strongest wind and the best spot for westerlies. Once we got there, the rain and chop made it quite uninviting. After driving up and down the bay looking in vain for a spot that was both flat deep enough, the final straw came when Hardie sent a screen shot from his top speed at Mandurah: he had gotten a 40-knot reading on his GT-31!

Back we drove, and sailed in Mandurah Bay at Coodanup. For once, it did not deserve the name "Fangy's Weed Farm", since a high storm surge covered the weed completely. The there actually was some chop - although it should more correctly be labeled "mini-chop", since it was just maybe 5 or 10 centimeters high. To keep things interesting, the weed had ganged up at some spots, building "weedbergs" (the weedy equivalent of icebergs) which were big enough for birds to stand on. Sailing into these at speed created interesting "sudden drag" situations, but the high-rake fins we used parted the weedbergs without catapults.

I ended up with a top 2-second speed of 33.6 knots and 32.6 knots for 5x10 seconds, which is the 3rd-best I ever did. Nina got two new personal bests for 2 seconds (32.6 knots) and 5x10 (31.5 knots). However, we both ended up disappointed, since our top speeds were about 5 knots slower than the speeds many others got, and almost 10 knots slower that the 42.3 knots that Stroppo, speed king of the day, posted!

Here's a summary of the local speed surfers' top speeds (2 seconds):
  • Fastest speed: 42.288 knots (Stroppo)
  • Above 40 knots: 5 sailors
  • 37-39.9 knots: 8 sailors
  • 31-34 knots: 9 sailors
  • Spots with 40+ knot results: Coodanup (3), Australind (1), Melville (1)
The numbers may change a bit since not everyone has posted yet; I think we'll see at least one 40+ knot posting.

Seeing these numbers made me feel a bit better, because we're at least in the largest group. The spread of 10 knots is quite amazing - what causes it? There is probably a small contribution that the gear makes. For example, whenever a heavy gust hit, Nina was very overpowered on her 5.0 meter sail and 54 cm speed board. Stroppo, who is close to twice her weight, used a 6.0 and a 47 speed board - no surprise he was able to stay in control! Sail sizes should (in first approximation) increase of decrease in proportion to weight, so Nina's sail should have been somewhere in the 3.x meter range, or at least much closer to 4 square meters. I was on a 5.6 m sail, which is close to what most guys my weight used. My board was an 89 l slalom board, and about 10 cm wider than the speed boards used by most others, which might have slowed me down by a couple of knots. Indeed, when I got hold of Nina's speed board for a run, I did immediately got my best speed of the day. But looking at the faster windsurfers, there's still a 3 to 5 knot difference between the fastest guys and the next group.

Our host Mike, who did 37.7 knots on a 4.7/43 combo, gave me his GPS tracks to compare to ours. Here is a polar diagram which shows the maximum speed relative to the wind direction for Nina (in red) and Mike (in blue):
The left half of the diagram shows the starboard tack runs, the right half the port tack runs. On starboard, Nina's and Mike's speed were about the same for most angles; but Mike went deeper downwind, and reached a slightly higher top speed at about 137 degrees. On the port tack (right side), Mike's speeds were about 2-3 knots faster than Nina's over a wide range. Again, he went deeper downwind, and got his top speed at about 145 degrees. Going about 15 degrees deeper increased his speed by about 3 knots.
After the session, Nina said that she simple could not go deeper because she was so overpowered. She was on a 5.0 m sail and a 54 cm wide board; Mike was on a 4.7 and a 43 cm wide board. Seeing how deep Mike's top speed angles were, he was certainly fully powered even on the deepest angles, where the apparent wind is significantly lower than when sailing on a beam reach (90 degrees to the wind).
The difference between the starboard and port tracks points to another very important factor: being familiar with the conditions. There was enough chop to make both Nina and me "put on the handbrakes" - we were definitely not going all-out. We both felt more comfortable doing speed runs on starboard, even though port was the better (inbound) direction. I think that is because at our typical sailing spot, Kalmus Beach in Hyannis, we generally go out against the chop, and come in more parallel and over the back of the chop. So we are much more used to dealing with chop on the starboard track.

It is also interesting to compare Mike's track to Stroppo's tracks, since Stroppo was significantly faster than anyone else. Here is the polar diagram (Mike in blue, Stroppo in green):

Stroppo did not do any speed runs on starboard, so we can ignore the left half of the diagram. On the port side, Stroppo was going a few knots faster than Mike, with a bigger difference at deeper angles - up to about 127 degrees. Beyond that, Stroppo's speeds actually dropped, while Mike's speed still increased for another 20 degrees or so.
The reason for this can be found in the sail sizes: 4.7 for Mike, 6.0 for Stroppo. But Stroppo is about 60% heavier than Mike, and sail sizes scale (roughly) proportional with body weight. For comparable power, Stroppo should have been on a 7.5! That seems way too big for the wind, so let's do it the other way around: for comparable power to Stroppo's 6.0, Mike should have been on a 3.7!
Arguably, the linear sail size relation does not fully hold for race sails; however, a sail closer to 4 square meters would have been more similar in power to Stroppo's 6.0.
Watching the two of them on the water, it was quite apparent that Stroppo was on the (relative) smaller gear: Mike had a much easier time to get going, while Stroppo often had to wait for gusts. The (relative) bigger sail enable Mike to go deeper downwind; but the smaller sail gave Stroppo more control in the big gusts, which he skillfully converted to more speed. Looking at the fastest runs for both of them, the top-speed angles varied a bit, but in general, Mike's top speeds were reached at a roughly 15 degrees deeper angle.

Another observation from Stroppo's tracks was that he did not do "slingshots", where the angle suddenly changes. Instead, Stroppo's angle changed very gradually to deeper and deeper angles - here is an example (from his second-fastest 2-second run, 41.18 knots):
The near-constant acceleration over the entire run is quite impressive. His fastest run look very similar, but he apparently caught a good gust near the end of it, which gave him the extra boost to reach a 1-second top speed of 42.4 knots. Very impressive! Since the technique is quite different from the slingshot, it deserves its own name - how about "Stroppo Curves"?

I must admit that I find Mike's speeds, and the speeds in the high 30s to low 40s many others had, almost as impressive. Mike is more than a decade older than I am, and must have been quite overpowered in the gusts, but had way more control to convert the gusts to speed than I did. Perhaps the more appropriate board (43 cm speed vs. 59 cm slalom) helped, but there's definitely a skill difference, too. But whatever the causes were, it was very fascinating to be able to share a great day on a fantastic spot with so many good speedsurfers!

Tuesday, January 22, 2019

Wave Sailing at Avalon

On Sunday, we left Geraldton and drove back to Mandurah, where Mike and Dorothy kindly offered us to stay in their home right at the beach at one of the wave spots, named Avalon. Yesterday, we got a bit of swell and just enough wind to plane, so Nina and Mike went out from the launch across the street (Nina on 4.7, Mike on 5.3). The wind was light enough to allow my little drone to fly. Since the break was close enough to the beach, I managed to get a bit of video footage. The breaks between the sets were large, and with my limited drone skills, I did not catch them on any decent wave rides, but I think the scenery and colors are quite beautiful:
I did not have wave gear to join them, but I later had a lovely flat water session at Liptons. I love the spot - perfectly flat water for jibing fun at both ends, with a mile-long run in between. The wind varies a bit, often being light in the middle and stronger towards shore, which is clearly visible in the GPS tracks:
The wind was a bit on the light side for my 7.0/112 combo, so no great speeds - but finally getting a relaxing session in flat water was fantastic!

Friday, January 18, 2019

Shark Bay and Lancelin

After Cervantes, we drove one hour south to Lancelin. Nina had booked us a very lovely apartment about 200 meters from the ocean. A couple of times, I rigged on the front lawn and carried my gear down to the beach for a quick session. That was fun the first time, but the second time, the wind direction had changed, and the runs were very short - after 400 meters (a quarter mile), a reef forced me to turn around. Jibing the 7 meter slalom sail every 30 seconds makes for a good workout, but gets old quickly. So the next time the wind was up, we went to the Ledge, where the Lancelin Ocean Classic marathon race starts. The start is nice and protected by a reef about 100 meters from shore. Once past the reef, there's big ocean swell; the place most similar that I have sailed is Jericoacoara past the point on a 4.5 m day. I generally sail my slalom gear only on flat water, so being out in head-to logo-high swell was quite interesting - but also fun. However, I certainly had no desire to sail a 22 km downwinder in a crowd of 100 windsurfers in these conditions!

Nina was thinking about participating, but there were a couple of issues. Once was that the race organizers announced two or three days before the races that they would require proof of liability insurance, and charge an extra $25 if you did not have it, bringing the total entry fee for the race to $125. In past years, Nina would have had a decent chance to recover some of the fee in prize money, but the organizers did not post any information about prize money anywhere. "No worries"?
The other thing that kept Nina from signing up was that her biggest wave sail was a 4.7, and she definitely did not want to do the race on a slalom sail. After pulling a muscle yesterday at Coronation trying to water start my 6.3 Racing Blade in the waves, I can understand that! Getting the sail out was hard enough, but then the next wave would come and kill the wind, dropping the sail right back onto my head. On the bright side, this keeps me from trying to go out again today with slalom gear on a wave spot, and gives me a bit of time for blogging while Nina is having fun on the water.

Back to the sail choice: one problem at Lancelin is that it's unpredictable when the wind will pick up - sometimes it is there for the race start around 2 pm, sometimes it comes half an hour or an hour later. Furthermore, some of the legs are very deep downwind, so bigger gear is needed - the winner (former PWA World Champion Matteo Iachino) was a 7.8. So there was a good chance that the 4.7 would have been too small - not something Nina wanted to bet $125 on.

While we did not race ourselves, we watched the start, and then drove back to the finish to see the first racers cross the finish line. It was quite a spectacle to see about 100 windsurfers and 90 kites at the starting lines! 

The next day, we got up very early (just about when the guys across the street finally ended their party), and drove 800 km (500 miles) to Shark Bay. We thought that we had picked great days to check out one of the best speed spots, with a wind forecast of around 22-25 knots and the tide levels being just right. However, after we had already made the decision to go and booked the hotel, we received a warning that the wind at Shark Bay tends to be 10 knots above the forecast! When we got to the beach in the afternoon, it did indeed look like at least 30 knots. We went for a quick test run just to verify that we could control our smallest speed sails in these conditions, but considering the lack of sleep and late time, we did not do the 2 km bay crossing to get to the speed strip. Instead, we decided to come back earlier the next day, before the wind got really strong.

That was a good plan, except that the wind did not quite play along. It kept blowing all night, and still was around 30-35 knots, with stronger gusts, when we got back to the launch around noon. The water level did not seem right, either: it was supposed to be a foot higher, but looked exactly the same as the day before. 

We cautiously made our way to the speed strip. We walked more than we sailed since we wanted to stay away from the deep water, as Nina was not sure she'd be able to water start or flip the sail. We were sure we had discovered the speed strip when we discovered the alpha markers - but the water levels were so low that sailing near the marker was not an option, even though our fins were just 18 and 20 cm short. Typically, the speed strip allows for a 600-800 m long approach in shallow and flat water, before the final "speed up" strip close to a sand bar and a deep sling shot close to the shore. But  given the shallow water, our approach was cut down to perhaps 50 or 100 meters, not enough to get settled and pick up speed - at least not with our limited skills. By the time we got back to the launch, the tide had gone down even further:
While we did not get to sail much, and did not get any speed runs, it was still a fun day. The area and the water was just beautiful - definitely one of the prettiest spots I have ever sailed.

The next day, we drove back south to Geraldton, our temporary home to check out Coronation Beach, one of the most famous wave spots in Australia. Shortly after leaving, we saw a family of emus right next to the street - cool!

The next stop was Eagle Bluff, which offers a great view of Shark Bay:
On the way to Geraldton, we stopped at Port Gregory, a small town best known for it's Pink Lake:
The pink color is due to carotenoid-producing halophine micro-algae, Dunaliella salina, which is used for cosmetics and dietary supplements. The town also spots a large reef-protected harbor:
One of the speedsurfers from Perth recently windfoiled there, and called it "foiling heaven". For speedsurfing, it's not quite as ideal, since the typical wind direction is at about a 45 degree angle to the reef, and waves break over the reef, creating some small chop and considerable current. But I certainly can see how this could be a great spot for foiling!

The next two days are predicted to be light wind days, which seems to be the typical pattern here: 2-3 days of light wind, then 4-5 days of good wind. When the good winds return, we'll be back in the Mandurah region for some speedsailing at the various Mandurah Bay spots. I can't wait!