Hank on vs. furler for Solent stay

[Dockhead]

Originally Posted by UNCIVILIZED

Boltrope in a foil = advantage over hanks, aerodynamically.

Hanks were used on the VO 70's because; to some degree keeping the sails in the luff grooves was problematic, & working the foredecks on those boats was a nightmare, given the large positive & negative G forces up near the bows. That & they were incredibly wet boats, with walls of water coming over the bows at speed causing it to be difficult enough for the crew to hold on, even tethered. Let alone do sail changes... while avoiding having sails washed away.

Which is why now, newer gen high performance mono's have more of their headsails on furlers, including structural furlers, & "downwind" sails.

But at the end of the day I think hanks are less aerodynamic.

Well all right then.

That is counter-intuitive to me -- the thinner stay would seem to slice through the air better, but I did read something somewhere which seemed to say that a fat bit at the leading edge is actually good -- like the mast in relation to the mainsail.

So the only drawback of putting the sail on a furler becomes the windage when it's furled. And I guess that's more of a theoretical question, since you can still pull the sail down, even if it's on a furler.

So if that is all correct, it means that furlers are kind of no-brainers, even if, like me, you strive to never ever reef headsails. Certainly makes is vastly easier to douse the sail when you need to do that quickly.

[brownoarsman]

Originally Posted by UNCIVILIZED

Boltrope in a foil = advantage over hanks, aerodynamically.

...

But at the end of the day I think hanks are less aerodynamic.

Hi Unciv, just because I'm slow and still haven't been able to grasp the terms fully yet, do you think aluminum extrusion-type foils for roller reefing are also more aerodynamic than hank-on?

[UNCIVILIZED]

Originally Posted by brownoarsman

Hi Unciv, just because I'm slow and still haven't been able to grasp the terms fully yet, do you think aluminum extrusion-type foils for roller reefing are also more aerodynamic than hank-on?

I think that a foil is better than hanks so long as the foil has a fairly aerodynamic shape. As a round foil will suffer much the same perils as a wire headstay.

Look at it this way, if you hold a cylindrical shape in a moving fluid, there are all kinds of ugly drag & eddy currents immediately behind the cylinder. And it takes quite a bit of distance aft of the cylinder for the flow of the fluid to smooth back out. But do this with an airfoil secton & there's relatively little drag or stray eddys. And the flow re-normalizes quite quickly. Including attaching itself to a sail if one's attached to it's aft end.

Basically it's because in the lee (behind the aft end) of the cylinder, there's a huge vacuum created when the air is forced around it's front edge & sides. So the fluid then wants to curl in behind the cylinder from both sides, within a very, very short distance no less. The thing is though, it can't do this, so there's a lot of turbulence for a long way in it's wake.

But with an airfoil shape, after the fluid passes the fattest part of the foil, it then too wants to come back together. However thanks to the aft sections of the foil, it's flow doesn't stall anywhere near as much, since there's little vacuum back there.

And picture in nature what shapes work best, especially at lower speeds. Be it a rain drop, a submarine, or even a destroyer hull. All have gently tapering aft ends, so that drag is minmized. Even high speed objects perform best when they have gently tapering aft ends, for the same reasons. Though their tip shapes are different. Going all the way back to "Glamorous Glennis" aka the X-1 aircraft piloted by Chuck Yeager that broke the sound barrier... unoffically named after his wife, Glennis.

[brownoarsman]

Thanks Unciv, that was very helpful for me. I do drive a first gen insight, so the teardrop example is not lost on me

Just wasn't sure if the fatter width of the aluminum extrusion foil meant the aerodynamic shape was lipstick on a pig to make a bad thing less bad, or if the shape more than made up for any losses due to greater weight, width, etc. (Edit: of course cost is a different matter! )

Thanks for a great explanation!

[jls095]

Originally Posted by Benz

To the issue of efficiency of hanks VS furlers: the OP has a Gulfstar--he should probably worry more about ease of use, expense of setup, and how to tack the jib rather than squeezing an extra fraction of a knot out of a not high-performance rig.

Thanks to everyone for the insight! I do worry about the extra windage of two furlers as well as weight aloft. That said, the ease of use and avoiding having the solent jib in a bag on the deck is appealing. I'm not too worried about tacking the genoa as I'd use the smaller jib upwind unless the wind was really light. Some friends with a Tartan 4000 (a twin furler Solent rig) found that the larger genoa provided no performance boost in light air upwind over the inner jib.

What isn't appealing is the price. A furler would likely cost $3000 by itself. Plus, I would be able to then use my hank on storm jib.

Is the bag on the deck and running up to douse the sail going to drive me nuts?

[UNCIVILIZED]

Originally Posted by jls095

Thanks to everyone for the insight! I do worry about the extra windage of two furlers as well as weight aloft. That said, the ease of use and avoiding having the solent jib in a bag on the deck is appealing. I'm not too worried about tacking the genoa as I'd use the smaller jib upwind unless the wind was really light. Some friends with a Tartan 4000 (a twin furler Solent rig) found that the larger genoa provided no performance boost in light air upwind over the inner jib.

What isn't appealing is the price. A furler would likely cost $3000 by itself. Plus, I would be able to then use my hank on storm jib.

Is the bag on the deck and running up to douse the sail going to drive me nuts?

The weight up high of 2 furlers & sails definitely affects a boat's stability, in addition to her windward ability if it's really blowing. So you're concern is a reality.

As to having the Solent not on a furler, it's not a handicap persay, just a bit more work. And those who are older, & less agile (or lazy) prefer to avoid much foredeck work. But really, folks got along quite well without roller furling for many decades. So it is optional. And being able to hang both heavy weather sails, as well as big, big light air sails on a conventional Solent Stay can be a big plus.

Spend some of the coin saved on said furler on a good autopilot if you don't already have one. It's probably the biggest labor saver there is, bar none. Though in many instances a wind vane works quite well too, & demands zero electrical power.

[Suijin]

Originally Posted by Dockhead

Does anyone (paging Unciv!) know whether hanked-on headsails are aerodynamically superior to ones on furlers?

I have read conflicting things and don't know what to believe. One version is that the fat bit of the furler foil is actually good for the air flow around the sail, although that doesn't "feel" right to me.

Well look at it this way; on racing boats sails go up thin foils. I think a continuous edge is more efficient than a hanked on sail, and I think it stands to reason that the foil itself be aerodynamic to minimize disturbed flow.

I'm going to guess that a foil is more efficient than a hanked on leading edge, but I suspect the difference is pretty minimal.

[Cheechako]

Not sure how you will use a furler that you can disconnect and bring back out of the way? If that is what you are talking. If not, then you are asking apples and oranges. So if we are talking a permanent stay, then it's just a matter of preference. A furler could be nice, albeit with the disadvantages noted.
I would keep it simple. Hank on with a proper deck storage bag. On my cutters I did this and at times even left the sheets run aft thru the fairleads. It worked very well, remove the bag , attach the halyard and your in business. KISS. On a bigger boat I may lean to a furler. It would be easy, albeit in a real blow a lot of windage up with two furlers.
What is your storm sail plan? A hanked on jib could be easily removed and replaced with a small heavy sail.

[jls095]

Originally Posted by UNCIVILIZED

The weight up high of 2 furlers & sails definitely affects a boat's stability, in addition to her windward ability if it's really blowing. So you're concern is a reality.

As to having the Solent not on a furler, it's not a handicap persay, just a bit more work. And those who are older, & less agile (or lazy) prefer to avoid much foredeck work. But really, folks got along quite well without roller furling for many decades. So it is optional. And being able to hang both heavy weather sails, as well as big, big light air sails on a conventional Solent Stay can be a big plus.

Spend some of the coin saved on said furler on a good autopilot if you don't already have one. It's probably the biggest labor saver there is, bar none. Though in many instances a wind vane works quite well too, & demands zero electrical power.

You're pushing me towards the hank on route, which I was favoring to begin with. I have no problem with bow work. Just 27 so not in the lazy camp yet! Also good advice on the autopilot - installed a below deck Simrad system last year to compliment my Monitor vane.

Originally Posted by Cheechako

Not sure how you will use a furler that you can disconnect and bring back out of the way? If that is what you are talking.
I would keep it simple. Hank on with a proper deck storage bag. On my cutters I did this and at times even left the sheets run aft thru the fairleads. It worked very well, remove the bag , attach the halyard and your in business. KISS.

Just talking about keeping the genoa on a furler and adding a removable stay about 12" back on the stem fitting for a hanked on sail as you describe. Glad to know that it worked well!

[Stu Jackson]

Originally Posted by Dockhead

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So if that is all correct, it means that furlers are kind of no-brainers, even if, like me, you strive to never ever reef headsails. Certainly makes is vastly easier to douse the sail when you need to do that quickly.

That is a very rational conclusion.

I have spent the past thirty years listening to "debates" about reefing headsails, mostly on sloops. One group has large (135-155) headsails, and either complains about poor performance when reefed or complains about being over-canvassed at times, or complains about the impossibility of balancing cloth weight and light to heavy wind speed operation. The other group suggests buying smaller headsails (110-120) because the difference in speed is not that much (http://forums.catalina.sailboatowner...d.php?t=155362) and smaller headsails can work over a much wider range of apparent wind speeds.

In sailing my current boat 18 years & on my previous 25 footer for 13 years on SF Bay, I had two headsails for each boat: summer 85% for the higher winds, and a winter 110% for lighter winds but it could also blow a lot after a storm came through. The smaller boat was hank on; I dropped the sail on the foredeck by heaving to at the end of a sail. This boat has furling. In all those years I only saw the need to deploy both hank on jibs in one day only ONCE; I used a technique I learned from a skipper in New Zealand to set them up on the bow for a quick change.

In your case, I agree that furlers make the most sense for ease of use and safety. The almost immeasurable difference in speed given the conditions you experience in your travels would not warrant going to hanks if indeed as some racers claim, they are faster. I believe one gets more out of properly cut shape & lead sheets than anything on the luff would do, and IIRC you did just that last year.

[savagebee]

If you go down the hank-on route I would highly recommend the following that has worked really well for us on our Allures 44.
Soft inner forestay, ours is vectran core with a hard-wearing outer cover but there are obviously other good options such as Dynice dux etc. that you could easily splice yourself.
Forestay attaches to deck using a wichard screw tensioning device with an integrated turning handle and snap shackle.
The staysail has soft hanks.
Staysail bag with zipper.

The whole hanked on staysail in the bag including forestay can easily be dragged back behind the mast out of the way for tacking or gybing of the genoa.

[Jim Cate]

Getting back to the aerodynamics of foils vs wires at the luff of a sail...

Not an expert at all, but looking at Unciv's description of flow fields around cylinders, one has to consider the effect of the sail being directly attached to the foil situation. Its presence has to influence the eddies formed in the wake of the foil, and I believe reduces the parasitic drag developed as a result. With wire and hanks, there is a biggish gap between the wire and the leading edge of the sail, allowing the turbulence to run rampant. Score one for foils. Further, (and this is a guess) beyond drag reduction, the foil configuration also helps keep flow attached on the leeward side of the sail. If you look at the way the foil and sail lie under load, you don't see the sail exiting the foil slot radially, but more nearly tangentially, providing a fairly smooth transition on the lee side. My intuitive thought is that this is a significant factor, especially with an oval foil shape. Score another for foils!

Despite all this, I suspect that even for folks (like DH) who really care about windward performance, for a non-racing boat these factors are pretty far down the significance curve. Fun to discuss, though!

Jim

[Cheechako]

Originally Posted by Jim Cate

Getting back to the aerodynamics of foils vs wires at the luff of a sail...

Not an expert at all, but looking at Unciv's description of flow fields around cylinders, one has to consider the effect of the sail being directly attached to the foil situation. Its presence has to influence the eddies formed in the wake of the foil, and I believe reduces the parasitic drag developed as a result. With wire and hanks, there is a biggish gap between the wire and the leading edge of the sail, allowing the turbulence to run rampant. Score one for foils. Further, (and this is a guess) beyond drag reduction, the foil configuration also helps keep flow attached on the leeward side of the sail. If you look at the way the foil and sail lie under load, you don't see the sail exiting the foil slot radially, but more nearly tangentially, providing a fairly smooth transition on the lee side. My intuitive thought is that this is a significant factor, especially with an oval foil shape. Score another for foils!

Despite all this, I suspect that even for folks (like DH) who really care about windward performance, for a non-racing boat these factors are pretty far down the significance curve. Fun to discuss, though!

Jim

Yeah, a big side road here in the discussion.

[DMCantor]

We have our solent sail on a furler, and after almost 10 years are very happy with the arrangement. Yes, rolling up the genoa when tacking or gybing is a bit of a pain. The main advantage of the furler is, well, furling. Our solent sail is cut very flat, and so you keep a pretty good sail shape when rolling it up to reduce sail area. It's not unusual for us to be out in 30kts of wind, and being able to simply reduce jib size is a real plus.

[Dockhead]

Originally Posted by Stu Jackson

That is a very rational conclusion.

I have spent the past thirty years listening to "debates" about reefing headsails, mostly on sloops. One group has large (135-155) headsails, and either complains about poor performance when reefed or complains about being over-canvassed at times, or complains about the impossibility of balancing cloth weight and light to heavy wind speed operation. The other group suggests buying smaller headsails (110-120) because the difference in speed is not that much (http://forums.catalina.sailboatowner...d.php?t=155362) and smaller headsails can work over a much wider range of apparent wind speeds.

In sailing my current boat 18 years & on my previous 25 footer for 13 years on SF Bay, I had two headsails for each boat: summer 85% for the higher winds, and a winter 110% for lighter winds but it could also blow a lot after a storm came through. The smaller boat was hank on; I dropped the sail on the foredeck by heaving to at the end of a sail. This boat has furling. In all those years I only saw the need to deploy both hank on jibs in one day only ONCE; I used a technique I learned from a skipper in New Zealand to set them up on the bow for a quick change.

In your case, I agree that furlers make the most sense for ease of use and safety. The almost immeasurable difference in speed given the conditions you experience in your travels would not warrant going to hanks if indeed as some racers claim, they are faster. I believe one gets more out of properly cut shape & lead sheets than anything on the luff would do, and IIRC you did just that last year.

Thanks; very interesting.

A hank-on sail (or a sail put up in a non-furling foil) might still make sense on something like a Solent stay, or for a staysail -- just to reduce the windage when the sail is not being used.

I have slowly come around to the realization that one of our biggest mistakes is trying to make a limited sail plan do too much. I love the cutter rig more and more with every passing year, and more and more I start to sail on either main or jib alone without the other, to get just the right amount of sail up without reefing anything. I even start to think that a ketch rig could be really great, if the boat were big enough and the masts could be far enough apart. Consciousness evolves!