Saturday, July 31, 2021

Silly Ideas

 Today was the day of silly ideas. It started before we even got to the beach, when Jay thought a 3-piece mast might work even better than a 2-piece mast. Silly! At least the water was warm enough for a 30 minute swim back to shore. 

I was barely foiling for 20 minutes when I came up with a silly idea of my own. After seeing Nina winging so nicely in so many sessions, I tried to partially imitate her. A key thing about winging is that the wing is not connected to the board. That can easily be copied with a windsurfing sail:

I forget a couple of little details though - the most important one being the to leashes that wingers use, one for the board and one for the wing. My board instantly realized my mistake, and took off to enjoy its newly found freedom. With a little help from chop and wind, it easily outpaced my tepid attempts of catching it again by swimming "fast". So I turned around and swam back to the rig, so I'd at least have some company. Fortunately, this being a nice summer weekend and all, a couple of motor boats quickly stopped by, after realizing I was not just swimming and waving at them to be friendly. The first one picked up my boat, the second one offered me a beer (just kidding!). Well, the second one asked if I was ok, and what they could do to help. They then drove to the other boat and told them to please, please deliver the board back to me, which they promptly did (big thanks to both boaters!). No major harm done, except perhaps for my ego.

On the way back to the launch, it was time for my foil to join the silly idea club. Apparently, the front wing was getting sick and tired of always being a foot or more under water, and decided to end the continuous drowning. Quite successfully so - after a surprise crash, I saw it happily swimming on top of the water. But I cut its dreams of escaping short by swimming after it, putting it on top of my board, and  stepping on it:
By then, the wind had picked up into the mid-20s, and my 5.0 m sail and Slingshot 84 wing had gotten a bit large, anyway. I actually planed a little bit on the way in - I guess the 90 cm mast is big enough to work as a fin. The foil setup looked a bit sad now:
That was my second Slingshot fuselage that broke. I blamed myself for the first one since I had drilled an extra hole to move the front wing further forward. But this time, the fuselage was not modified, and the screws were still nice and tight. I checked the GoPro video, and there was no obstacle in the water, either. Sure, the Slingshot fuses are relatively cheap, but replacing them on a somewhat regular basis because they break seems like a silly idea - and I've had it with silly ideas right now. I think I'll pay a little extra from more solidly engineered gear from other brands in the future.

Here are the GPS tracks from today's session:

Saturday, July 24, 2021

Foil Jibes, Big Feet, and Forgetfulness

Back in February, I posted about a foil session where I had tons of good foil jibes, thanks to help from Andy Brandt. I should have known that would not last! After all, Andy also taught me how to plane through windsurf jibes ... and then, I had to take another dozen ABK camps where he had to jog my memory how to jibe properly. He was usually able to fix my problems within an hour. But in the weeks and months after a camp, I'd start forgetting, and went back to practicing bad old habits instead.

Windsurfers have to be optimists, so I hoped that this would not repeat itself with foil jibing. But whenever I tried to jibe back home on Cape Cod, a typical result would look like this:

Well, perhaps not always this flashy, but usually wet. Which is a real bummer, since I got that faster foil which really calls for using big cambered sails - sails that I really do not want to waterstart or uphaul all the time!

I was coming close to resigning myself to a lifetime of foil tacks when my endless hours browsing windsurf and windfoil forums paid off. A fellow foiler whom I had met in Corpus Christi posted a picture on Seabreeze that illustrated what had helped him to foil through jibes. The key was to have both feet pointing forward, towards the nose of the board. So a couple of foil sessions ago, when my initial foil attempts had resulted in the usual crashes, I tried his tip. Immediately, my jibes remained dry! They may still have been ugly as hell, with lots of wobbling, but at least I was not falling anymore!

A look at the GoPro footage from the session reveals that the differences in foot orientation were much smaller than I thought. Here's how my feet were placed in the initial crashed jibes:

Note that the back foot is almost perpendicular to the long axis of the board.
For comparison, here's a screen shot from a later (dry) jibe where I tried to have the toes pointing forward:

The difference in foot orientation is much smaller than I thought - maybe a 20 degree difference for both front and back foot. The feet are also closer together in the long direction of the board, as can be seen by looking at the distance from the front heel and the back toes to the black line on the board. This means that smaller steps are required during the foot change. Together, these changes made the "dry rate" in the jibes go from 20% to more than 80%. So far, so good!

Thursday was another great day to work on foil jibes at Kalmus. Just check out the wind graph:

Some Kalmus windsurfers may want to point out that northerly directions are not so great at Kalmus, and use the lulls of 5 mph and gusts up to 25 mph as "proof". But then, neither would they go out in the 10-13 mph averages that we had at the beginning of the session! But northerly wind directions are offshore at Kalmus, meaning the water is very flat. Just perfect for jibe practice! You don't need to be an expert to enjoy the conditions, either - Joanie, who is still a foil beginner, had some very nice long foil rides today with her 5.4 m sail. 
My only goal for today's session was to focus on the foot work in jibes - the initial setup with feet pointing forward, and a smooth(-ish) foot switch. I jibed 15 times in the 2 hour session today. 14 of those jibes were dry, which I am quite happy with. Some where nicer than others; today's GoPro footage was quite useful to get hints about what might cause the problems, and what to try to fix them.

In a few of the uglier jibes, the sail flip felt very unbalanced, and I often had to grab the mast instead of going boom-to-boom. Here's an example screen shot:
That sail has gotten away from me, forcing me to bend over. But why? A look at the board gives a hint: the leeside edge of the board is in the water. That means that the board is carving in the wrong direction! That's clearly visible in the GPS data for this jibe:

During the sail flip, the board turns back by about 15 degrees within one second. That does not really help to complete the jibe! But worse, it puts the sail in a pretty bad position - it's pretty much flagging out to the front of the board. No wonder something felt off!

To understand why this happened, we can look back a bit further in the video:
Check the placement of the old front foot as it is stepping back. The entire foot is on the wrong side of the center line - the lee side. As soon as I lift the old back foot to step forward, this will reverse the carving direction of the board! 
For comparison, here is the foot position at the same point in one of the better jibes of the day:
The new back foot stepped about a couple of inches closer to the old back foot, which makes it straddle the centerline of the board. With weight on the heel of the new back foot, the board will keep turning the right way even as I step forward with the old back foot. Indeed, the GPS tracks for this jibe show that the board kept carving about 10 degrees, from 148 degrees to the wind to 138 degrees. That's 25 degrees better, just because the foot placement is a couple of inches different! With the board continuing to turn the right way, the sail flip on this jibe was easy:

Maybe the jibe was not perfect, but I was able to keep the speed above 7 knots, which let me get right back onto the foil after the sail flip - good enough for me!

So the question arises: how can I make sure that the front foot steps back to exactly the right place? One possible solution would be to put the older carving foot further to the outside of the board, so that there is more space for that big front foot as it steps back. But when I tried this in the past, a new problem occurred: when lifting the old front foot to step back, the board tilted a lot, which often resulted in a crash. That sometimes made for great screen shots, where it look like I'm trying rail rides with a foil - but it did not make for dry jibes. In other tries, I would feel the board starting to tilt when the old front foot started to move, and I'd cut the step short to prevent the board from tilting. That, however, would leave it on the wrong side of the board again! So while the tip to "move the carving foot all the way to the outside" may work for some foilers, it does not work for me.

But let's have another look at the last picture above, where the sail flip worked well enough. You can see that both of my feet are in front of the foot pads - in other words, too far forward. That means that the board will go down and touch the water, and won't start flying again until I moved both feet back again. For the goal of fully foiled jibes without water contact, that's not good enough. It is, however, very typical for my "good" jibes: even in my session in Corpus Christi, where I almost foiled cleanly through many jibes, the board would often touch touch briefly just after the sail flip (or, in sail first jibes, the foot switch).

So I really have two problems, let's call them "wrong side" and "too far forward". My lovely wife never experienced these problems, and I think that's simply because her feet are a lot smaller, so it's much easier to find space on the board. Unfortunately, blaming my big feet does not really help. What might help, however, is stepping heel-to-heel, making sure I feel the foot that moves back actually touch the heel of the old back foot. That would place the back foot a bit further back, and the heel on the correct (windward) side of the centerline. If we now assume a constant size for the step forward, the front foot should also end up a bit further back. That would be progress.

But one of the things that I glossed over somewhat was that in the initial setup, I move the feet closer to each other in relation to the long axis of the board: the back foot goes forward a bit, and the front foot goes back a bit. That allows for smaller front-to-back steps during the foot switch, which in turn leads to a steadier flight. To "undo" this, it may be necessary to modify the foot placement during the switch: the old front foot steps behind the old back foot (but still heel to heel). That should make it easier to keep the old back foot from stepping too far forward, and it also should give the foil a little push up to get flying again, or to keep flying. I can't wait to get back onto the water to try!

Sunday, July 4, 2021

New foils

I's been windy lately - we've been on the water 7 days in a row at the end of June. Perhaps my definition of "windy" has changed a bit since we started foiling, considering that I was on the foil most of the time, and on the slapper only 2 days, plus part of a couple more days. On the days with better forecasts, there were quite a few people at Kalmus. On some of the very hot afternoons, though, the windsurfers often spend their time re-rigging or waiting for more wind, which often showed up late in the afternoon. On the foil, it did not matter much if the wind was 15 or 25 miles per hour - once we made it out, we usually had plenty of fun. 

As long as the wind comes from SW or WSW, flat water is never far away. On one of the windier days, I even managed to get an Egg Island session on the slapper in, together with Jon. I just love going into a jibe  on flat water at full speed:

But whereas most of my turns on the slapper are jibes, I usually tack on the foil. Here's an example in the flat water on the other side of Kalmus, at the Kennedy Slicks:

On the way to and from the slicks, there is usually some fun chop to play with. That's just an incredible amount of fun, even on the big Slingshot Infinity 84 foil:

Here are the GPS tracks from this session:

After a couple of years on Slingshot foils, we wanted to check out new things. Nina had read a lot about higher aspect foils for winging, and Phil from Inland Sea was happy to let her try his Armstrong foil. He knew why! Nina at first had a bit of a hard time to get going, since the foil is quite a bit smaller than the i84 and i99 foils she had used so far. But once up on the foil, she absolutely loved it, so of course she bought one. It certainly did not hurt that the foil weighs less than half of the (significantly cheaper) Slingshot foils, and that the engineering seem much more solid - but the feeling when foiling was the main motivator. Whereas I make tiny little turns down the waves with some power in the sail, she can often be seen riding swell with the wing flagged out, and a big smile on her face, doing full bottom turns and then going back up the same wave - or perhaps the next, since we're talking about Kalmus, after all. Even though more speed was not a goal in this change, she has gotten quite a bit faster. In the past, I could usually pass her easily with my foil (partly because I need a lot more speed so the foil generates enough lift to push all my extra pounds above the water). But now, her speed matches mine, even when she's just winging along, and I try to catch her.

This, of course, created an untenable situation. I needed a faster foil! Never mind that other windfoilers have posted much faster speeds on the foils I have. I tried plenty of times, but for me, going significantly faster than 15 knots on my i84 was a really hard thing to do. My typical cruising speeds were closer to 12 knots. Surely, faster foils would fix the problem!

I got on the North Beach Windsurfing web site and started a chat with Karen and Britt, who not only know a lot more about fast foils, but also sell them. We exchanged some pictures of fuselages to figure out what would work, and I ended up buying a Starboard GT-R Plus foil with a 95+ fuselage, 85 cm mast, and 800 front wing. If arrived quickly, and after some more help from Britt over the phone, I was even able to put it together.

Of course, I had to try the new foil right away, so we went foiling even though the wind looked marginal. I rigged my 7.8 m freerace, 3-cam sail to have a chance to get going. I also put a cheap phone into a waterproof armband and had it announce my speed - after all, I was going to be on a fast foil!

I got the foil out of the water on my very first run. But after about 30 yards on the foil, there was a loud "bang", and I crashed. In less than 15 minutes, and after fewer than 100 attempts to pump up onto the foil without any success, I realized that something must be wrong, and turned the board over. Instead of pointing straight up, the mast of the foil now was tilted at a 30 degree angle. The back screw in the tuttle box had come out! Fortunately, the other screw had held (although I later noticed a pronounced S-turn in it when I disassembled the gear). Back to the beach (slowly!); to the car to get a new screw (a longer one that actually reached the barrel nut this time); and back onto the water. Ah, much better!

Being a rather cautious person with a strong aversion to high-speed catapults, I proceeded to investigate the low-speed potential of my new foil. I pumped a but harder than necessary on my i84, and when I heard "10" (knots) from my phone, I'd step on the tail to pop the foil out of the water. Up I went! And then, I plopped straight back down. I repeated this multiple times, before I finally realized that I needed a speed of about 13 knots before the foil would fly consistently. That actually makes sense - for my i84, I need about 8-9 knots, but the i84 is about 2.5 times larger, and has a much thicker profile. The bigger difference, though, is how to get the foils going. With the i84, I need just a bit of board speed before I step on the tail to pop up, and then accelerate once flying. With the GT-R+, I need to reach about 12 knots before going up. Which, actually, has one big advantage: I get a much better workout!

When powered, the foil made it quite clear that it wants to go fast. Whereas I have to work hard to push the i84 over 15 knots, the GT-R with the 800 front wing definitely wants to go faster. The phone often announced 16 or 17 knots, even though I was doing what I could to slow things down! For a slow learner like me, it will take a bit to get comfortable with higher speeds when foiling with an 85 cm mast in 90+ cm chop. Sure, the GT-R is not nearly as affected by the up-and-down motion that waves and chop create in the water, but it is still affected somewhat

For my 4th session on the GT-R, I finally got some flat water: offshore NE wind at Kalmus! It may have been a bit gusty, with meter readings between 8 and 28 mph, but between the lulls and big gusts, there was a range where it was just real fun to sail along. At least until the next big, fat gust hit, which would want to make the foil come out of the water - either because I tried to sheet out, which takes pressure of the nose, or simply because the foil started going faster, which generates more lift. Interestingly, the rhythm of this setup is very different from the i84 - partly because of the much longer fuselage. That makes the foil less nervous, but it also makes it a bit slower and harder to push the nose down when it wants to come up. I'll definitely need a few more practice sessions before I get used to this!

Despite my general efforts to keep things slow and controlled, I ended up finally going faster than 20 knots on a foil. My 2-second top speed was just below 20 knots, but that's still 2 knots faster than the top speed on the i84, which I got in very flat water (the Kennedy Slicks) on a day with stronger and more consistent wind. That felt just about as fast as doing 35 knots on a slalom board - and definitely faster than the 29 knots I had done a couple of days earlier at Egg Island on my freestyle board. Being a foot or two above the water, with the prospect of a full speed catapult if you let the foil rise just one more foot, must distort the perception! But should I ever get used to this feeling, the setup should be able to go at least 5 or 6 knots faster. And after that, there are smaller front and back wings for even more speed!

For the time being, though, I'll probably grab my Slingshot foil for many of my foil sessions. Slowly playing with chop and swell is plenty of fun, and the shorter 71 cm Slingshot mast works better for sessions near low tide. But it's great to have the option for a very different level of foiling fun!