Furled sail limiting upwind ability

I have a question for some of you experienced sailors who can maybe explain, and help me understand upwind performance of our boats due to the wind dynamics on a furled sail.

I have often had difficultly with the upwind ability of the TI especially in strong winds. I always blame it on a combination of lots of chop, currents, and not enough daggarboard. However, the other day I did something that made a huge difference in the upwind ability that seemed counterintuitive.

I was sailing in probably 13 - 16 mph winds with gusts several mph higher, and going into 1+ feet of chop. I had the sail furled about half way. I was making extremely slow progress upwind. I had the nose pointed as close as I could get it into the wind, so my speed was slow. Due to the angle going into the chop, I didn't want to go too fast, and I also didn't want to lose ground since I was having difficulty making my way upwind. A completely unfurled sail was way too much on a reach, and a jibe across the wind with a fully open sail was a bit scary, thus my furled sail.

I'm not sure exactly why I did it, but at one point I found myself with a completely unfurled sail, and what do you know, I'm making serious upwind progress! I still had the boat pointed very close into the wind to keep my speed down, but the upwind performance was night and day. As far as the jibes...well I'll admit, sometimes scary equals fun.

So can anyone explain this phenomenon? This seems contrary to how it should work.

Furling is usually benificial on my AI at around 16mph. When you hit that point where the amas start diving its like back or white. No shades of gray. the boat slows and you have to furl. now you moving faster than when submarining but not faster than just befor when at full sail. Right up to that moment full sail was giving you the best performace. So maybe, the winds momentarily dropped from 16 to 14 where you again hit that sweet spot allowing you to show a full sail- just before the amas start to bury. Would be my guess.

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Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

What you are describing is one of the most powerful features of the Adventure boats and also the most daring.
Most of the time I am out this is how I sail upwind (even in very high winds).
Obviously you have to be extremely careful and maintain the strictest rudder control. If the boat gets away from you you will capsize for sure.
Also keep in mind it's been over 5 yrs since I ever tried to use my TI without a jib (I sailed it twice with no jib when I first got the boat, it sucked so bad, never attempted it again) so I have no clue if this technique even works without a jib.
Basically what I do is point directly into the wind while pedaling. I then open the sail all the way and pull it as tight as I can (really tight). The boat naturally rounds into the wind and stalls (thats a good thing). During all this time you have to be continously pedaling (if you stop pedaling you are totally screwed and in very serious trouble). You might have to pedal pretty hard at first to get the un-natural sailing condition going, but once going you can relax your pedal pace.
Now in my case (mostly because of my jib, I have no idea what point of sail it grabs without a jib (you will have to experiment)). In my case I carefully turn off the wind until the main bites (on my boat thats 5 degrees off the wind), you feel a huge lurch and you are on your way. You have to keep tight control of the rudder, and you had better not stop pedaling (really screwed if you do (just FYI)).
Keep in mind this is not a natural sailing mode and extremely dangerous. If you get more than around 20 deg off the wind there is no way to release the sail fast enough to keep from going over in winds over 15mph (ask me how I know this (lol)). Also in higher winds your likely to snap the mast if it gets out of control on you.
I'll be perfectly honest, since figuring all this out, I haven't tacked ever in the last 5 1/2 yrs, no need my best point of sail is into the wind and actually my worst point of sail is a reach.
Before adding wing sails a couple yrs ago (using just regular jibs), I could count on being able sail up wind in 15mph or higher winds and maintain a good 4-5 mph almost directly upwind. Giving me the best VMG, whereas if tacking I might sail a little faster (typically around 6mph), but at 45 degrees you are only going half that forward.
Figuring all this out was my main reason for going into wing sails. Since wings work on apparent wind, you get the most apparent wind velocity almost directly into the wind (wing is amplifying at max efficiency), so in my case just switching from a regular jib to a wing I can easily cruise upwind at 8mph vs the previous 4mph.
I just assumed everybody sailed this way always.
Don't wanna see anyone get hurt, trying all this stupid crap that I do though, and my boat is pretty extensively modded out, like I said earlier I have no clue if these techniques will even work on a stock TI.
FE

Here's what happened - with sail all the way out and feathered/pinched to the wind, you were sailing inefficiently (which is what you needed to do to sail safely in those winds). So even with all the sail out you weren't getting maximum power. But you were getting a little more than you were with the sail furled and sailing a bit lower. It's almost six of one and a half dozen of the other.

You could have achieved the same thing with the sail furled a bit and just steered a little bit more off the wind.

You don't say how hard you had the mainsail sheeted. If I'm guessing, I suspect it wasn't that tight--so the front part of the sail (back to about half) was pointed directly into the wind so only the last half was angled to the wind. This gives you what amounts to a very large wing mast. The camber in this combination is "positioned" pretty far forward so you get good forward drive. The "problem" as you doubtless found out was that a gust destabilizes the "system" since the mainsail won't reorient quickly--so you have to be quick (ie, don't cleat the mainsheet, keep it in your hand so you can let it go when you get scared); makes for an exciting sail. If you want your gybes to be safer in this combo, reef first, then gybe, then release more mainsheet. Tacking shouldn't be as much problem.

Part of the reason the boat is so lubberly when reefed is the shape of the mainsail. When fully deployed the mainsail camber is properly placed for going to weather at about 40% forward. As soon as you reef even a little, any camber you have is at best 50% which means you can't point worth a darn. It is safer, but slow. If you routinely sail in big winds, it might be wise to invest in a radial head pintop mainsail that is a little smaller (and no battens). If the camber is properly positioned in the radial head--it will still be pretty well positioned as you reef so you can still point.

BTW, this is not just theoretical rhetoric...I design and make sails. My triak exhibited the same horrible lubberliness in bigger wind, adverse current and chop. Once I designed and built a radial head pintop, my enjoyment of the boat increased dramatically for higher wind conditions. What was surprising was that I also was just as fast off the wind with stock triaks and faster than stock upwind (pointed higher)-in lighter breeze. Granted, I was more experienced than the folks I was sailing with--which is pretty much always the case anymore.

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R/Thom
SeaRail 19
Triak
BMW C600
Formerly Getaway with Custom Spinnakers
Formerly raced F24 Mk II

I can't wait to try this out, having a hard time believing that the boat will sail as close as 5 degrees to the wind.

I too would love to see a GPS generated track confirming this capability. My TI won't go near that...

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Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

On a standard TI without a jib, I have no idea what that angle would be, but guessing with the sail as tight as you can get it, I'm just guessing here but it prabably catches at around 15 degrees off the wind, but doesn't provide much forward propulsion until you get to around 20 deg off the wind while pedaling (obviously you have to be pedaling (sometimes pretty hard, much easier with two peddlers) for all this to work, most are not wiiling to do that)). Don't take my word for it, simply try it next time your out in higher winds.
With a standard jib you can likely improve that by around 5-10 deg (which makes sense, this is what jibs are for, to direct focused air over the main to improve pointing).
With a wing jib you can get even closer, and the wing jib is twice as efficient at accelerating the organized air over the back side of the main (basically kind of forcing the main to work even if it doesn't want to).
I don't understand it all fully myself, I just know it all works really well on my rig (which is modified a little), my main reason for adding a jib a long time ago was so I could sail this way (up wind), haven't ran without a jib rigged and running on the boat since the first two times I sailed the boat, both times I got caught out in the gulf and couldn't get back in, probably because I suck at sailing, so I fixed the boat so it would do what I wanted to do in the area I live.

Here is a link to description of sailing angles.
http://team-moto.org/2013/01/09/Success ... Weinstein/
Note that an Etchells (highly efficient one-design) can not sail closer than 25 degrees off the wind.

I appreciate that one can pedal an Island directly into the wind

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Tony Stott
2012 Tandem Island "SIC EM" with Hobie spinnaker

Many of your posts include stuff that is "bad gouge" in Navy parlance. That's OK, it is up to the readers to figure out when something makes sense and when it doesn't.

As far as sailing close to the wind while pedaling goes...duh, of course. Bigger boats call this motor sailing.

As far as sailing (without motor) as close as 5 degrees or 15 degrees even...nope, won't work in an island. HOWEVER, you probably think you are that high because you are looking at telltales and those look like they are streaming parallel to the ama. It is called apparent wind. The true wind direction, though, is probably around 45.

A jib's job is not to push wind over the mainsail. Next you will be talking about slot effect...sheesh!

Granted, it is difficult to learn sail dynamics, sailing dynamics, etc. on the internet...it is because there is so little science and so much bs. I have an advantage since one of my degrees is in physics. I can recommend Frank Bethwaite's book, "High Performance Sailing" as a primer.

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R/Thom
SeaRail 19
Triak
BMW C600
Formerly Getaway with Custom Spinnakers
Formerly raced F24 Mk II

Likely the poor performance upwind is related to what is called "crabbing". Pointing too high is also called "pinching". Crabbing is slipping sideways because there is not enough water flow over the centerboard and rudder.

As noted by comments above... steer away from the wind a bit to increase speed and even pedal a bit. This gets the water flowing over the rudder and centerboard, then try turning slightly back up wind and watch for a speed decrease. Keep the boat moving for better upwind performance even if you have to turn away from the wind a bit. Once the full sail was out, likely the forward speed increase was enough to limit the crabbing effect.

There is a term / effect that I use called Parallax to judge if you are slipping sideways or able to hold course.

You need a few objects one close and another further away. In straight line of your course is best... you can see if they stay in alignment or relative position or if they are shifting (moving apart or closer together). In a river flow or tide shift you can use this to change your heading to maintain a course to a destination. You may be pointing any number of degrees away from the destination, but with tidal or river flow... end up at the desired destination.

Once in a race on San Francisco Bay with the tide moving out at 5-6 knots... sailing between two marks in a straight line required a heading at about 20 degrees below the next mark (into the current)... crews that didn't figure that out sailed a huge arc and ended up well upwind of the mark. We used parallax and simply kept the two onshore objects in alignment.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Thanks for all of the really good suggestions and information here. This is all very helpful and gives me a lot to think about.


I actually had the sail as tight as I could get it. Really good information in your post.



For the TI, what do you think the minimum speed is, assuming no currents, to prevent the crabbing effect?
I didn't have a GPS, but it seemed as if my speed was very similar when I unfurled the sail. My guess is I was going no more than 4 mph with it furled. But if 1 or 2 mph makes a difference in counteracting this affect, this very well could have been the case when I opened the sail up.

Tpdavis473 later today I will post a new topic on jib physics inclìuding what is really happening in the slot. I'll share my thoughts but would love to get everyones take on it. Interesting topic.

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Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

Can happen at any speed... Over sheeting the sail also can stall the speed and cause this.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Interesting....wish I had figured that one out a long time ago. I always thought the more you wanted to point into the wind, the tighter you should sheet the sail. Good thing I'm not entering any races.