USA-Technical Details-Helium used

[Paul B]

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No guess-fact.(approximately)

So what is "fact"?

You don't give a reason, you give several guesses.

So, is this a claim that you know the helium was used to make the boat lighter, therefore shorter on the WL so it would rate?

Or was it to lighten the boat and reduce the RM?

 

[peterraymond]

$'s per second

There are one or two areas where AC rules, in the past, limited technology to control costs. Hard as that is to believe.

With a lead sled you can get densities significantly higher than lead. Tungsten is a lot more expensive, although it is used in darts. You know, the kind that get thrown around in bars. Depleted Uranium is banned too. But, why stick to depleted Uranium? I think Iran has some spare 238 they'd sell cheap. Wonder why they are working so hard to get that lightweight 235 stuff.

There have also been some limits on materials for stays too. Maybe Helium needs to be added to the list.

Pressurizing structures is used to prevent buckling in materials so thin that you get skin buckling under compression loads. If they were to pressurize anything on USA-17, I would guess the floats. They are fairly round in cross section and pressure might allow the deck to be thinner and not buckle. I doubt it, but maybe.

I do know that before the race everyone was worried that the BOR boat was heavier than the Swiss boat. There is some theoretical advantage, but it sure is small. To me it seems like this is a story that wasn't supposed to be released till this Thursday.

 

[Chris Ostlind]

... I might add, you sailboat types seem to be a mean spirited bunch. I appreciate the discussion and tossing about of ideas - perhaps being very constrained by a requisite for substance leads to stagnation. Sailboats don't work very well in stagnation, I reckon - Design, neither.

While I respect your observation about the speculative tossing about of ideas, Mark, perhaps you can share with us how the helium speculation magically transforms itself into the following quote from one certain member...?

"UPDATE: this is fact and is one of the most exciting, incredible developments in design and construction of high speed sailboats that I have run into in my 50+ years of studying design and sailing. Monumental is not too strong a word!!" (ridiulous red color and monster, screaming font omitted by posting member)

The above pasage looks to me to be very much an out and out statement of fact... well, according the person making the quote, that is. Others are saying, "uhhh, wait just a minute there. What say you produce said mystery man and we'll have a crack at his comments once he produces the photos showing the whole thing in operation."

Because this is a more, or less, techy driven kind of website, (with hints of the liberal arts tossed in for flavor) it's kinda incumbent upon he who makes such claims, to produce said supporting material. So, it seems to me that the tough crowd questions are appropriate in this case.

 

[Doug Lord]

I think that the use of helium, for whatever reason, in an Americas Cup is significant. But, remember the article said it was used to make the hull fly earlier.
So lets look at a few guesstimates:
-est. max lift of the helium in 3 hulls= 500lb.
-est. boat+ rig weight= 25,000lb.
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Now, just for the heck of it a 175lb crewman moved from the lee hull to the windward hull would generate about(87 X 175) 15,225 ft. lb. of RM.
The helium would reduce RM by approx.( 42 X 500) 21,000 ft.lb..
Now lets compare that to the approx. RM of the whole boat( 25,000 X 42) which is 1,050,000 ft. lb.(!) So the helium would reduce RM by 2 %. Is that enough for a serious gain? Maybe.
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Lets look at it from another angle. Lets say you had a hull that absolutely,unequivocally had to measure in at exactly 90' or less. The approximate pounds per inch immersion on that hull would be ([90 X 9] X .65) X .083=43.65 cu. ft.=2796lb. Now, lets say that the hull was floating just a few milimeters too deep, how would you lighten it assuming, for the sake of discussion, that everything that could be removed had been removed. Well, its very interesting that the approximately 500lb of lift from the helium in three hulls would change the immersion of the boat by .179" or 4.5mm......
Could the helium have been a measurement device with somewhat minor, but positive, side effects?
Just an idea....

=================
Both suppositions are relatively accurate according to the best info I have so far from two sources one of whom wishes to remain confidential. The other source is spelled out in post #1.

 

[ancient kayaker]

Hmmm! I would have thought there were easier ways to reduce the weight of a hull. I would start by tossing the Helium cylinders over the side, followed by the guy who thought of it. As for filling the rig with Helium, with such a tall rig the internal pressure at the mast peak might be a nuisance.

Come to that, it's not that easy to replace air in an enclosure with helium, you would have to purge it thoroughly. It's not as simple as replacing the air in a narrow enclosure such as a double-glazed window with a heavy gas like Argon.

Maybe they inserted a bladder? Now there's a thought. With a bladder in each ama one could use pumps to exchange Helium in one ama with Argon in the other ama! This would provide adjustable righting moment in the event that the entire boat became lighter-than-air and left the water. Really guys, you have to think outside the box ... or the planet ...

If there is any basis to the use of Helium, it's for some other purpose. But with a donkey engine on board to operate a compressor if compressed gas was needed, what could it possibly be? Maybe the skipper inhales it so he becomes a tenor and his voice carries further!

 

[Paul B]

With a bladder in each ama one could use pumps to exchange Helium in one ama with Argon in the other ama!

I have not sailed on a boat with helium or argon gas aboard, but in the 80's sailed quite often on boats with Nitrous Oxide aboard.

 

[ancient kayaker]

Now we're all outside the box. They'll never get us back in again! Just thought of another explanation; they could release the Helium under water to generate drive, like a Putt-Putt boat. This would create a characteristic sound, which I have been able to simulate on occasion in the bathtub ...

 

[basildog]

Come on Mr Lord,
Who was this mysterious person, show us their name or it didn't happen.

 

[mark775]

Wow! Maybe you are right - I missed the part about helium "cylinders". "it's not that easy to replace air in an enclosure with helium" - Actually, I have refilled MRIs with liquid helium (all along the border - trying to keep up with the Canadian demand) after bonehead doctors push the big red button that says "don't push the big red button." It is a bit dangerous but it is quite simple. That's liquid helium.
A standard gas cylinder will fill 100 cubic feet at two atmosheres and it would be hardly more difficult than filling a child's balloon (a small valve at the opposite end of the chamber, at the bottom of the volume, slowly displace atmosphere then close valve and dump in a second atmosphere). I cannot imagine not filling amas to save wall thickness or interior framing, now that I think of it. If the one to five hundred pounds of air saved was at one atmosphere, double that at two, and subtract a thousand more for reduced framing - starting to add up! I think I need to sell my ideas to AC teams and you guys need to lighten up. He was asked not to disclose his source - that should be the end of it. Pick on me and my ignorance instead of Doug and his exuberance.

 

[TeddyDiver]

Come to that, it's not that easy to replace air in an enclosure with helium, you would have to purge it thoroughly. It's not as simple as replacing the air in a narrow enclosure such as a double-glazed window with a heavy gas like Argon.

Maybe they inserted a bladder?

The bladder is one way to get rid of air too. Or just use water as usually. No problem with a floating hull.. And Mark is right "I cannot imagine not filling amas to save wall thickness or interior framing, now that I think of it. If the one to five hundred pounds of air saved was at one atmosphere, double that at two, and subtract a thousand more for reduced framing - starting to add up!" and if you allready have an airtight space so why not to fill it with smth lighter..

 

[CT 249]

Compare a section (or an entire hull) to a liter plastic bottle of coke - atmosphere inside and one can crush it like a... liter plastic bottle. Pressurise it, and it is as hard (stiff) as a rock. You guys are the engineers but, to me, it seems not only possible but likely that hulls be pressurised. I could build a like-sized vessel that weighs less than the BMWO that could survive thirteen knot winds as long as nobody had to enter. My skills don't lead to a proper shape or strong enough attachment points but if amas or other specific vessels (contained areas) are not being designed this way, why not?
I might add, you sailboat types seem to be a mean spirited bunch. I appreciate the discussion and tossing about of ideas - perhaps being very constrained by a requisite for substance leads to stagnation. Sailboats don't work very well in stagnation, I reckon - Design, neither.

And Mark, where is your evidence that design has moved faster in other areas of popular sport? As an old example - when Benetton were winning in F1, they used to link their desktop computers overnight to run their aerodynamics prediction programme. At the same time, one back-of-pack AC teams were using the fourth (IIRC) most powerful supercomputer in the world for its VPP, and runs were taking longer. IT guys I've asked haven't been able to put into words how much more complex the sailing programme was.

Put it another way - F1 and yachts got into carbon at about the same time. And do you really think building the world's largest wing is the act of a bunch of luddites? The designer behind the world record in human powered flight and boating was involved; is he the sort of person to get into a low-level effort? Or, to look at another engineer, we see that he's got a PhD from a university ranked #4 in the world in at least one major study. Is he really less qualified than you are to design a proper structure?

Yes, one could design a boat lighter than BMWO. However, keeping the rig tension and rigidity is the issue.

Do you really think all those naval architects, engineers, materials scientists and boatbuilders are so blindingly stupid that you could do better than them? To fail to give credit to them, and to other sailors, seems extraordinarily mean-spirited.

 

[ancient kayaker]

I got all excited and considered filling the floatation volumes of my small sailboat with Helium.

Weight reduction, 95 gm. 3 oz.

Oh! While it is a very small and lightweight boat, with my weight added, that isn't going to do an awful lot.

Simpler to leave off that extra coat of paint I was planning for the Spring. Or skip lunch.

 

[BWD]

Who was this mysterious person, show us their name or it didn't happen.

Odds are it's the one person involved in the project with whom Lord has been documented to have conversed previously.
Hint: "foil" related.

Of course, could be wrong...

 

[themanshed]

On the lighter side I like to inhale helium from balloons it makes my voice funny!

 

[mark775]

Okay...the real naysayer first - maybe I was a bit hard on you guys. "Yes, please do approach any of the AC teams with your ideas" - I was fully tongue-in-cheek at this point and I hope you are, too.
"Being able to pour liquid helium into MRE bags (MRE means "Meal, Ready to Eat) and calling that comparable is also leaning towards funny" - the helium is contained in a giant "Thermos" bottle, cooled by liquid nitrogen for transport and refrigeration to keep it from evaporating (no amount of styrofoam would work). I was merely pointing out that it is not that difficult to work with gas when even dunderheads such as me can work with the cold stuff. Teddy's suggestion of water is better than mine and fool-proof.
"I'm no expert at this stuff, but it would seem to me that there are all sorts of serious issues with gas containment. When one wants to pressure load a gas, composed of the second smallest atomic structure known... into a hull that is going to haul-***, go through huge racking, twisting, pounding, etc., movements, there would seem to be some fairly big problems to overcome just to keep it from leaking out through the tiniest of openings in the composite structure. But, hey, I'm no rocket scientist and there is a guy on this forum who says he is. ;-) Maybe he could offer-up an opinion? Maybe he's even Doug's Deepthroat in a darkened garage?" - yes, it will bleed out over a short time (days), just like a child's balloon. A balloon that costs .03 pennies to make.
I suppose that I am not that up on the journalistic standards but I just hate seeing somebody get picked on. I, personally, would enjoy the forum much more not necessarily sans crack or flaw but, at least, egos. Sometimes I am guilty.
Now, the one who must not have read any posts but mine and responded as if I was knocking the AC designers (CT scanner?)...Read again, then retract or look stupid. I was comparing as if "even I could do it" - not in any way diminishing their abilities. Come on, you can do it...it goes like this; "I guess I misunderstood Mark's intent and barked at him for no reason. I'll come up with another reason because I don't like him or admit that I just wanted to chime in with the big barking dogs. Sorry, Mark."
Where's Doug? Come defend yourself, Doug! - I have to go to work. (can't wait to see him post proof!)