Sunday, July 30, 2017

Borderline Breaks

The things we can learn from board repairs ... for example where you should not put your feet. Let's start with the end:
This is my blue Skate 110 which I bought to replace the white Skate 110 that I wrote about in my previous post. The picture shows the end result of my latest repair attempt. If you click on the image to see the larger picture, you'll notice a slightly different blue in the repaired area, which extents from the back of the pad to the edge of the board at the "F", and extends forward to the "N".

I discovered a soft spot towards the rear of this area last fall. Upon exploring, I discovered that the glass and the PVC foam underneath had a break. I dug out the core foam all the way to the sandwich at the bottom of the board, filled the void with polyurethane (PU) foam, and glassed it over. The PU foam is harder than the original EPS core, forming a hard "plug" that connects the bottom and the top - good enough, I though.

When putting the fiber glass on top, I noticed bubbles forming: the new structure had several little "pinholes". The inside of the board was still under a bit of pressure, and the air coming out pretty much kept the little holes open. I tried to fix this with an extra coat of epoxy while the board was cooling off, hoping this would pull the epoxy in and close the pin hole in the process. However, this did not work as expected, and I saw bubbles forming after a few sessions.

The next repair attempt including removing the glass around the pin holes, and glassing the entire area over again. This repair held for a couple of month, but then I noted a new soft spot right next to the initial repair. I used some Solarez since it was freestyle time, but that barely held for one session. So .. time to try again.

When I opened the board up, I saw that the initial repair was still intact; however, the top glass fiber layers were broken right at the edge of the repair. When I made the initial repair, I did not rebuild the PVC sandwich layer because I had neither divinicell nor the vacuum setup. I figured that having the PU plug extend to the bottom would make it stable enough; but what I had not considered was that I would have a hard plug right next to the somewhat softer, slightly elastic sandwich construction. This create a "Sollbruchstelle", which then indeed created a break.

This time, I tried to do things right. The first step was to open up a relative large area that included the previous repair area, and digging out all the soft EPS foam. I then hooked up the area to a vacuum pump to see if I could draw any moisture. This removed some slight dampness from the top of the EPS foam, but the vacuum trap remained empty after several hours. Fortunately, very little water had gotten into the board.

The next step was rebuilding the foam core with PU foam:
That was followed by sanding the excess foam off, and removing additional foam to allow re-building of the PVC sandwich. After some filling, glassing, and sanding, here's what the repair area looked like:
When you look closely, you'll notice a slightly different color along the top and right side. This is the edge of wood veneer reinforcement. It extends about two thirds of the way to the edge  near the front of the repair area, but not nearly as far at the back. The original soft spot that had developed had definitely not been covered by wood.

Using wood veneer as reinforcement under the rear footstraps makes a lot of sense, since wood has excellent mechanical properties to absorb and distribute the impact after jumps. Extending the wood past the padding makes sense, too: the padding under the foot pads is not very wide, and my size 12 feet need to be quite deep in the foot straps for my heel to be on the padding. Most of the time, however, I sail with just my toes in the foot straps, so my heel rests on the board next to the foot straps. I must say that I find it somewhat peculiar that the wood reinforcement did not extend further back. There are several possible reasons for this, like to much deck curvature, or "interference" by the fin box. Whatever the reasons were, it seems my heels were often positioned right next to the reinforcements, which eventually led to damage. It's no surprise that the damage was on the right side of the board, either: my home spot Kalmus had starboard jumps most of the time. Even when not jumping, just going over the chop there would put a lot of stress on the back heel, which does not even have any padding underneath.

I am quite sure that the reinforcements in my older Skate 110 were quite different. I use the old Skate a lot more often than the new one, and often with bigger fins, which lead to more outboard foot placements and more back foot pressure, but the old Skate never got soft in the back. The old Skate seemed to have a lot of carbon reinforcement, while the new Skate seems to have wood veneer instead (although the areas I repaired on the two Skates are different). But mainly, the old Skate 110 actually had two sets of footstrap positions, including a more outside one that's missing on the new Skate; and the padding on the old Skate extends further to the rails. So placing the back foot more outside on the old Skates was not a problem, but it appears to be a problem on the new Skate, at least when sailing in heavy chop or jumping a lot. Maybe I just need to go to tiny little freestyle fins to enforce a more centered foot placement and less back foot pressure...

Thursday, July 27, 2017

Fixing My Favorite Board

In 2010, I got a white Fanatic Skate 110, and it has been my favorite board ever since. But last year, I discovered that the deck near the front foot straps was getting soft. My favorite board repair guy, Donnie in Hatteras, did not want to repair it, so I figured I'd use it to learn board repairs on. The first installment was a big nose job last fall. A while later, bubbles started to come out near the soft area, so it was time to learn new stuff - soft deck and sandwich repair! Most of the things I did are based on the excellent instructions on "The Board Lady" web site.

The first step was to take the padding under the front foot steps of:
That took a while. I started to understand why Donnie did not want to do the repair.

A small exploratory cut was next:
You can see the sandwich construction: a few layers of glass fiber on top, then a thin (~4 mm) layer of high density foam, a single layer of glass, and the EPS foam core. The sandwich looks good, but there's a big air gap that should not be there. It seems the EPS foam got compressed just too many times and eventually tore apart.

I enlarged the cut-out area, but the soft area was quite large, so I decided to treat most of the affected area with expanding polyurethane foam, introduced through many little holes that are covered with blue tape in the next picture:

You can see the foam expanding all the way into the cut-out area. In the cut-out area, I removed some of the damaged EPS foam, so I had to build the area back up, also with marine polyurethane foam:
I just love playing with the pour foam. You mix together a couple of liquids, and then you have about a minute to inject it before it expands about 50-fold. Fun!

After sanding down the PU foam, the next step was to rebuild the sandwich layer. I used one layer of glass and two layers of thin divinycell. To press everything together, a vacuum setup is needed, as shown in the next picture:
Once you have the stuff and know how to use it, this is easy. The PVC foam must be covered with three layers of different plastics: perforated release film, then "breather" material, and finally vacuum bagging film. This was the first time I did this, so I made one small mistake: I put the sticky stuff that connects the vacuum bagging film to the board to close to the treated area. That made it a pain to take off later!

I also had to close all the little holes I had drilled to get the PU foam into the board to fill the air spaces. That required some sanding first, and then some epoxy and lots of small little glass fiber discs:
Once the epoxy had hardened, each of the little holes needed to be sanded again to smooth things out and to get a good feathering connection between the new and the old glass.

The divinycell also needed to be sanded down and glassed over. I used two layers of glass, but no carbon. The original construction appears to have a layer of carbon cloth on top, but it's very thin; you can see in the next image that I accidentally sanded through it at a few spots.

The board came with two sets of foot strap positions, inner and outer. I never used the outer positions, so I simply filled the holes in the outer plugs with some epoxy mixed with low density filler (the brown stuff). The next step will be to add one more layer of glass over the entire center area; some sanding and filling; putting new padding down; and painting over all the little holes (more to protect the epoxy from UV than for cosmetic purposes).

This repair has already taken quite a few hours, and still needs more work. Someone who repairs boards professionally would have to charge at least $400-500 for such a job, and even that assumes he'd be a lot faster than I was, and that he'd charge an hourly rate much lower than what I have to pay a local car repair shop. How long the repair will last is an open question, so I can definitely see why Donnie did not want to do this.

For me, however, this was fun, and a useful learning experience. The Skate in the pictures above is not the "Team Edition" model, but this repair clearly shows that it still contained quite a bit of carbon - it looks like at least one thing layer of carbon cloth over most or all of the top. In contrast, the 2015 Fanatic Skate that I got as a replacement did not seem to have carbon reinforcements, at least not at the places I looked so far; instead, the 5 years newer models appears to use wood for reinforcing (more about that in a future post). I always had the impression that my blue 2015 Skate was not quite as lively as my white 2010 model - but the newer models seemed a bit easier to sail in very choppy conditions. I now think that this is because only the older model has the extra layer of carbon, which gives it a bit more stiffness. So I'll be very glad when I can sail my white Skate again on the lighter wind days!

Wednesday, July 26, 2017

Reality Check

I'm venting. You've been warned.

Surfer 1 says to surfer 2: "I'm a much better surfer than you! I bet I was at least 3 knots faster than you!"

It's pretty funny someone would say such a thing, but this did indeed happen. Not only is surfer 1 faster than surfer 2 - no, almost every single day, he is a lot faster than anyone else at the beach! He must be a better windsurfer than all of them!

We could argue that surfer 1 is usually the only one on slalom gear on the beach, or that he sails more than 95% of the other windsurfers, but let's not go there. For the last 2 years, surfer 1 has used a GPS to record his sessions - so how well is he doing? Easy to find out on the GPS Team Challenge web site, which has rankings for 6 different speed disciplines:
Surfer 1 is highlighted in red, so we'll simply call him Chris M. from now on. Surfer 2 is highlighted in yellow. The astute observer might notice that this appears to be the writer of this blog - congratulations!

I'll readily admit that I am not a good speedsurfer. In the international rankings on the GPS Team Challenge, there are somewhere between 840 and 900 speedsurfers who are faster than I am. On our team, there are several guys who sail a lot less than I do, but have much higher top speeds, and will usually be several knots faster when we sail together, even if we are on similar gear. But I don't care much - I do my "slow speedsurfing" when it's fun, and my (equally poor) old school freestyle / freeriding when I want to fall a lot, or it's just too bumpy for my taste. After more than 3 decades of windsurfing, just going back and forth at moderate speeds still is utterly fascinating to me. I don't think I'll ever loose this fascination - fellow local Bruce has not, and he's 20 years older than I am.

But back to the rankings. As bad as I am as a speedsurfer, I still managed to leave Chris M. several spots behind me in 5 of the 6 categories. If I'm not good, what does it make him? The guy who is always on slalom gear? Let's check the overall ranking:
9th overall in a field of 27 (which includes a bunch of freestylers who "volunteered" to take a GPS so that we'd get a second ranking for the team). He barely manages to edge out the lovely Nina, who'll be on freestyle gear at least 9 out of 10 days, hacking away at Flakas, Vulcans, Switch Konos, and Switch Vulcans. I have no problem admitting that Nina has become a way better windsurfer than I am; the same is true for the guys ahead of me in the rankings, and for a few that place behind me (including Bart, Martin, and Graham, who is playing in a whole different league). But Chris M.? Now that's a rather funny thought. Maybe if he shows me a few planing upwind and downwind 360s, and beats me in the rankings. Not that that will ever happen - in the past two years, he has not been able to figure out install GPS analysis software, or use ka72.com, or even to use the software after I installed it on his laptop.

Looking at the rankings reminds me of another funny story. Less than half a mile from Kalmus is Egg Island, which is a very nice speedsurfing strip. I've been there several times with different guys on from our team. The first sessions were with Dean, who did his usual complaining half the time, but still racked up several 35-knot sessions. Boro sailed there just a couple of times in lighter winds, but managed to set a 37-knot spot record the very first time he sailed there. Chris M., you ask? I've seen him there twice. The second time, the wind picked up a few knots, so when I go got to Egg Island a few minutes after him, he was standing on shore, complaining that he could not sail in "this shit", and that he was so far away from his next-smaller sail. He did a wonderful job at defining the opposite of impressive! When the guard came to tell him that he was standing on a private beach, he sailed back to Kalmus, never to be seen at Egg Island again.

Some of my regular readers may wonder about this post, since I usually try to write about positive or at least interesting things (which some non-geeks may, admittedly, debate). Well, I must admit that I have a very low tolerance for stupidity, arrogance, and selfishness. I'm do not really have a problem if someone is not intelligent or well educated. I have worked with mentally handicapped people, and they were some of the nicest people I ever met. I have also met many nice and good people who had little or no education. But people who are ignorant but think and proclaim they know it all? Like "real estate developers" who "know" more about climate science than thousands of scientists? Keep them away from me! The same goes for self-taught windsurfers who never in decades of windsurfing bothered to learn the rules, and think "oh, it's just like when getting out of the elevator". Really? How stupid do you have to be to think that's a good way when two people on windsurf gear approach each other at a combined speed of 50 mph or more? How stupid and arrogant do you have to be to yell at someone "there are no rules in windsurfing" because you don't know them? Someone who not only learned the rules when he learned windsurfing, but also is a certified windsurfing instructor with a rather good understanding of what US Sailing, US Windsurfing, the UK sailing association, the VDWS, and the top US windsurfing instructors have to say about this issue? Really, really, really stupid and arrogant.

But believe it or not, this entire thing was not really about rules - it was about attitude. I realize that there are windsurfers out there who don't know or understand what the rules are that apply when they are on a collision course. Even windsurfers who know the the rules and play by them sometimes mess us. Usually, we still figure out how to stay out of each others way. In the rare case of a near-accident or a forced fall, things can usually be sorted out with a few friendly words or an apology. But things are a lot easier and more predictable if you know the "right of way" rules, and play by them. There are plenty of windsurfers on the beach who can explain them - including anyone who ever did an ABK camp (and paid attention in the very first lecture).

But if you happen to be the "give-way" windsurfer in what could become a collision, and you force the other person to jump of the board to avoid the collision, you've got a problem. If you think you are a good windsurfer and the other person is not, and you force them off the board, something is wrong with you. If the other windsurfer is a (slightly) older lady, other choice words come to mind.

And still, everyone does stupid things sometimes, and a simple apology can fix things. If someone who feels you treated them wrong when you forced them off the board approaches you, a simple "I'm sorry" would do. Or if your understanding of what should have happened differs, you could discuss it, and perhaps ask others for feedback. But being dismissive and calling the other person a "bad windsurfer" instead? Or later calling the women that you forced of her board a "cranky old fucker" to their friends? That shows some serious moral and mental deficits.

And still, this all would have ended after my last post. I had revised my assessment of Chris M. from "a bit rough on the edges" to "ignorant sociopath", and decided to avoid him - there are plenty of nicer people to talk to on the beach. I am certain that my intentions were very clear, but Chris M. deemed them unacceptable. When we happend to both sail at Duxbury in a NE wind a few days ago, he just had to approach me to ask if we were "friends or enemies". My explanation that I will not be friends with someone who calls other friends "cranky old fuckers" had him come to the conclusion that we now must be enemies, and he proceeded to explain to me that "there are no rules in windsurfing", that "rules are just for races", that "it's just like when you get out of the elevator", and that "only bad windsurfers complain to me".  Given my low tolerance to ignorant idiocy, you can imagine the rest. Even the Duxbury Harbor Master stopped by to make sure we were not fighting; unfortunately, he had no desire to explain the sailing rules to Chris, either (smart man!).

Well, enough venting. I'll end this with a citation from the "Start Windsurfing Right!" book from US Sailing (2nd Edition, p. 103):
"There is also an unspoken rule among sailors which should be considered part of your sailor's code. When two boards meet, it is common courtesy for the more experience person to maneuver around the less experienced one".

Sunday, July 9, 2017

Stand On or Give Way?

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

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

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

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

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

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

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

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

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

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

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

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

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

Tuesday, July 4, 2017

Destroyer

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

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

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

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

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