65 knots is 75mph or 120kph

[SpecialK]

smoke 'yer balls

http://www.youtube.com/watch?v=pipGWQme ... e=youtu.be" onclick="window.open(this.href);return false;

[scumbag]

Holy shit... I would have loved to see it get up to speed.

[DerGolgo]

Wind power and speed records, now there's an odd couple. Well, not that odd, technically the world's first "land speed record" was set by some sort of sail-driven cart some dutchmen knocked together in the 16th century, the "zeilwagen", fastest thing on land in it's day.
I have zero care for this sailing or yachting or catamaraning or what you call it, but that they can get to these kinds of speeds with literally zero horsepower is kinda impressive!

[SpecialK]

I think you'd have to call it "speed-recording" or something. I'd go so far as to guess that what that guy experienced was far more similar to piloting a gonzo Bonneville sidecar than to any kind of sailing that I've ever done. What I find really crazy about this is the magnitude of difference between the speed of this boat and the speed of a typical local raceboat. The average theoretical top speed of a 30' racer/cruiser is about 6.5 knots. Meaning that the record is almost 10x the speed of a normal fast boat. For comparison the wheel driven land speed record is 414 mph, or only a little over twice as fast as new Camaro.

[Mk3]

So I'm a little confused. THe awesomeness is abhorently clear, but here is my conundrum. Is the wind blowing at 75mph for this? if not how does the boat go faster than the wind? does it work like a pulse jet? If so how?

I'm hung up on the technicalities and am ruining a youtube load of awesome for myself in the process.

[DerGolgo]

120 kph winds are the kind of weather that results in disaster warnings and great calamity over here, probably not quite as much at the coast as it does inland, but I'd doubt anyone would take a flimsy little sailboat out in such weather. I don't know much about the sea, but I'd bet that in that sort of wind, just the waves would make a skipper think twice. But, I admit, before arriving at that conclusion, I was thinking about how clever, airfoil like aerodynamics might be used to create greater force than the wind just blowing against a straight surface. Then I decided to be smart about this question.

God, I love how we live in the age of google. Within three seconds, two and a half of which was typing in the query, the guys from Redmond delivered:

http://en.wikipedia.org/wiki/Sailing_fa ... n_the_wind

The Extreme 40 catamaran can sail at 35 knots (65 km/h; 40 mph) in 20–25-knot (37–46 km/h; 23–29 mph) winds.

For me, this is doubly impressive. Not just using a force of nature to go, not just using a force of nature to go very fucking fast, but using that force of nature to bloody outrun nature itself. Were I a man with a hat, that hat would be off. But being a man without a hat, I'll just hum the safety dance in appreciation.

To translate an appropriate German saying, and daring to imagine what an expert may say about this: At this, the layman marvels and the expert is astonished.

[JoJoLesh]

....The average theoretical top speed of a 30' racer/cruiser is about 6.5 knots. .....

? I think I have issue with this statement. It may be cleared up by your use of the word "theoretical ", but ....
I sailed a Catalina 30 (fin keel), that i remember getting 9 knots out of in good conditions. That was nowhere near a racer/cruiser. A also recall getting 12 knots out of a Catalina 36 (wing keel), rigged for cruising. I am no awesome sailor either.

Anyhow, this record is a amazing feat of engineering. I am both happy for this team and for the sailing sports, as this shows again that sailing is not dead.

[Sisyphus]

Well, ther're a couple things at work here; namely that it can only do what it does because it's a non-displacement multihull. There's not a lot of boat in the water.
When you're comparing that to a 30' displacement hull, which actually has a hull speed of about 7 knots, there's really no comparison. Totally different animals.
Iceboats are capable of achieving greater than 65 kts. Most of those records are in mph, I think the current record is about 150 mph. I've gone as fast as maybe 40 mph in an iceboat; three times that is probably pretty disturbing.

[MATPOC]

This is pretty cool, I'm not a "sailor" as my name might suggest (MATPOC is Cyrillic for Sailor) but I did wind surf for a while and sailed once or twice, 120 kph is absolutely insane speed on choppy water, at 20 kph will rattle your teeth, 6x that is hard to imagine.

[DerGolgo]

This is pretty cool, I'm not a "sailor" as my name might suggest (MATPOC is Cyrillic for Sailor) but I did wind surf for a while and sailed once or twice, 120 kph is absolutely insane speed on choppy water, at 20 kph will rattle your teeth, 6x that is hard to imagine.

Now, there is one for Mythbusters! Does sailing on choppy waters actually get ever more uncomfortable with increasing speed, or is there a speed at which you'd just fly from wave to wave without much of a dip, a speed at which the choppy waters in effect feel like they were flat, or at least not quite as choppy? Questions involving not just amplitude, frequency and quantifications of "comfortable" regarding these two, and speed, of course, but also expensive machines and vast, literally uncontrollable forces. Heh, that would be awesome.

Come to think of it, didn't they at some point do a myth about square wheels or driving on railroad tracks where they found a smoothing-out-at-speed effect for cars?

[Rabbit_Fighter]

So I'm a little confused. THe awesomeness is abhorently clear, but here is my conundrum. Is the wind blowing at 75mph for this? if not how does the boat go faster than the wind? does it work like a pulse jet? If so how?

I'm hung up on the technicalities and am ruining a youtube load of awesome for myself in the process.

How? SCIENCE!

[Sisyphus]

So I'm a little confused. THe awesomeness is abhorently clear, but here is my conundrum. Is the wind blowing at 75mph for this? if not how does the boat go faster than the wind? does it work like a pulse jet? If so how?

I'm hung up on the technicalities and am ruining a youtube load of awesome for myself in the process.

No, the wind is blowing maybe all of 20 kts. The way the sail works is like this: Imagine an airplane wing in section. It has a certain shape to it that affords lift when the wind blows over it. A sail is cut to make the fabric take that shape. All it needs is the right shape to create a high and low pressure side on opposite sides of the curves. This creates lift, moving the sail--and anything attached to it. Depending on the specific shape of the sail (flatter ones go upwind better) and how it's angled toward the wind direction, the further upwind it can point.
Eventually the boat gains speed, which has the effect of increasing airflow over the sail, which in turn delivers more power transmitted through the mast to the hull.
This boat is a nondisplacement hull. The only thing keeping it in the water is probably some sort of finned keel and the rudder; this provides lateral resistance so the boat doesn't just go sideways, it makes it possible to go upwind.

[Rabbit_Fighter]

Another thought.

Put a wedge shaped piece of wood on a table and lube it. Push down firmly with your hand and that fucker is going to shoot out sideways really fast.

[SpecialK]

Yeah,I pulled the 6.5 kt number right out of my ass. And I was trying to make a couple of comparisons with normal sporty real-world things. I think the camaro/keelboat comparison is reasonably valid.

Anyway, I've tried to beat my head against some of the aerodynamics of this stuff and it gets crazy dense really fast. Basically like Sisyphus said if you're going roughly into the wind then the faster you go the faster the wind you are going to feel. It's called "apparent wind". From what I've read it seems like a really really fast non-displacement boat in ideal conditions should be able to get close to 2.4x wind speed. I guess the skiff guys are able to pull that off with some sort of regularity.


Also ice is bad-assed surface. I wish I had more.

[Sisyphus]

Ice is awesome, but man--if there was ever an argument for full-face helmets, that'd be it. The wind chill at any speed while iceboating is through the roof.
A friend of mine was director of the Kingston Maritime Museum, where they keep Icicle, a gaff-rigged iceboat that regularly would do speeds in excess of 80 mph back in the day when the Hudson River actually froze. I think the "boat" belonged to Roosevelt, but I'm not sure. It's BIG.

[JoJoLesh]

......
Anyway, I've tried to beat my head against some of the aerodynamics of this stuff and it gets crazy dense really fast. Basically like Sisyphus said if you're going roughly into the wind then the faster you go the faster the wind you are going to feel. It's called "apparent wind". From what I've read it seems like a really really fast non-displacement boat in ideal conditions should be able to get close to 2.4x wind speed. I guess the skiff guys are able to pull that off with some sort of regularity.


Also ice is bad-assed surface. I wish I had more.

w/ a cruiser, I considered myself doing well to get 1/2 of wind speed (apparent)
You are correct in that Apparent Wind is what to look at. True Wind is only useful in planning out your next move.

[Rabbit_Fighter]

Ice is awesome, but man--if there was ever an argument for full-face helmets, that'd be it. The wind chill at any speed while iceboating is through the roof.
A friend of mine was director of the Kingston Maritime Museum, where they keep Icicle, a gaff-rigged iceboat that regularly would do speeds in excess of 80 mph back in the day when the Hudson River actually froze. I think the "boat" belonged to Roosevelt, but I'm not sure. It's BIG.

[DerGolgo]

A friend of mine was director of the Kingston Maritime Museum, where they keep Icicle, a gaff-rigged iceboat that regularly would do speeds in excess of 80 mph back in the day when the Hudson River actually froze. I think the "boat" belonged to Roosevelt, but I'm not sure. It's BIG.

Was it this one?
http://en.wikipedia.org/wiki/Icicle_(yacht)

In 1871 "Icicle" beats the "Chicago Express" train on a run between Poughkeepsie and Ossining.

That is a fast "boat".

[Sisyphus]

Yeah, that's it. Not THE Roosevelt I thought, but yes. That's it.

[Mk3]

Tried to read and comprehend, too much eggnog for that. I am instead contending that Bernoulli fuck-starts it and it goes like stink.

One of the things that gets me now (being a non sailor in landlocked texohma) wouldn't your sail/wing/underpants occilate madly at thepoint when you could no longer draw it in and change the angle of the wind vs thrust? I know, I'm sucking all of the fun out of the rocketless rocket boat. Any way, once you hit that equallibrium why doesn't the sail fuck it I'm out due to the equalized pressure and then the boat slow down and start over? or is that the entire nature of sailing and I'm a tard.

Mind you, as I type this my wife thinks I'm doing interpretive dance as i hand-wave out what I think is happening to a sail vs. a wing vs my undies under pressure from a good chili night.

screw it I'll stick to rockets. It's mullet warfare, business in the front party in the back.

[DerGolgo]

Any way, once you hit that equallibrium why doesn't the sail fuck it I'm out due to the equalized pressure and then the boat slow down and start over? or is that the entire nature of sailing and I'm a tard.

The speed at which the boat moves would depend entirely on the effective wind speed they get with their clever sailing, so it should work like a self-regulating system, shouldn't it? When it gets to the point where it would start oscillating, it stops getting faster, so it won't oscillate. Some sort of equilibrium is achieved. That would be my landlubbers guess.

[Sisyphus]

It's kind of like a turbo, the faster you go the more power you make. The limit becomes wind and water resistance.
If you look at the BMW Oracle. Same principles apply; the faster you go the more lift you have, the faster you go...

[SpecialK]

The other thing that happens (and we're getting well into my confusion zone) is that the sail sets up a "circulation flow field" that is entirely distinct from the actual wind that a spectator would experience. Apperently the longer a sail is in action the stronger this circulation field becomes. This sets up some sort of system that essentially "organizes" the air in the area surrounding the boat in a way that is beneficial for producing lift.
You could probably start reading about it here: http://www.arvelgentry.com/origins_of_lift.htm" onclick="window.open(this.href);return false;

I started reading a book about it called "Sail Performance Theory and Practice" like I said, it got over my head pretty quickly.