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Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261633
07/24/13 12:18 AM
07/24/13 12:18 AM
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Long Beach, California
John Williams Offline
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I've taken some private flak for picking NZL early; I hope some of the folks who may be bent at my surety realize that, not only do I believe that they have the fastest boat upon the sea (tip o' the hat, Cap'n Nat), but I also feel some national pride in the work done by Nat Shaver, Bobby Kleinschmit and Pete Melvin, all members of my Club, who picked up sticks to live in New Zealand for over two years to get to this point. Hat's off.


John Williams

- The harder you practice, the luckier you get -
Gary Player, pro golfer

After watching Lionel Messi play, I realize I need to sail harder.
-- Have You Seen This? --
Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261636
07/24/13 03:14 AM
07/24/13 03:14 AM
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Tony_F18 Offline
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Did you guys catch the comment about the effect of current on apparent wind?
Didn't hear all of it but the idea was that sailing with the current reduces apparent wind and their by overall speed.

Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261637
07/24/13 04:55 AM
07/24/13 04:55 AM
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Greenville SC
bacho Offline
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I heard it, I can't seem to figure out how that would work. Kinda put it up there is some of the other really silly stuff they have said.

Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261638
07/24/13 05:20 AM
07/24/13 05:20 AM
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Tony_F18 Offline
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I think one of the Oracle sailors told them about it so some information may have gotten lost in translation.
It does kind of make sense, if the current takes you in the same direction as the wind you lose some wind speed.
I have noticed this myself while sailing but don't think sailing against the current is worth it at the speeds that we do?

Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261639
07/24/13 06:17 AM
07/24/13 06:17 AM
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Petten Netherlands
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northsea junkie Offline
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I think something is lost in the translation and/or the transmission of this remark.

Look, apparent wind is the resultant of the true wind in the sail and the boatspeed in opposite direction. The last is derived from the so-called groundspeed.

So, when the current is with you, your groundspeed will be higher then in the situation when the current is against you.

This will certainly effect the apparant wind; this app.wind will increase and will be turned more to the bow (more close-hauled).

If you will lose boatspeed because of that effect, will finally depend on the boat. The boatspeed will even want to be higher because of this increased (apparant) wind (the speed was already higher because of the current).

Only problem is the direction of the apparant wind which is more and more close-hauled!


ronald
RAIDER-15 (homebuilt)

hey boy, what did you do over there, alone far out at sea?..
"huh....., that's the only place where I'm happy, sir.
Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261640
07/24/13 06:21 AM
07/24/13 06:21 AM
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Greenville SC
bacho Offline
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We're they (ETNZ at least) not sailing downwind when that comment was made?Seems that sailing with the current would increase the apparent wind downhill.

Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261641
07/24/13 06:46 AM
07/24/13 06:46 AM
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brucat Offline
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These guys are quite often right, but could certainly use some John Madden-like graphics to walk us through the logic.

With all the technical wizardry, why is there no announcer's pen so they can draw right on the screen? TV weather reporters have this, after all...

Mike

Re: AC72 Oracle Team USA Spaceship has landed [Re: Tony_F18] #261644
07/24/13 07:33 AM
07/24/13 07:33 AM
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Posts: 2,490
On the Water
P.M. Offline OP
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Originally Posted by Tony_F18
I think one of the Oracle sailors told them about it so some information may have gotten lost in translation.

I'm guessing has more to do with less efficiency/lift of the foils. Probably does sound like it was lost in translation.


Philip
USA #1006
Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261645
07/24/13 07:41 AM
07/24/13 07:41 AM
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Posts: 302
Daytona Beach Florida
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Daytona Beach Florida
Glad these races are short. With these kind of blowouts imagine a 3 hour race(more than boring). I was watching the Utube live feed view count and it was only about 8K. Not very high. And after 2 legs I was only checking back every few min to see if anything interesting had happened.
If NZ is blowing out Luna this bad imagine how bad the racing will be against Artimis.

Re: AC72 Oracle Team USA Spaceship has landed [Re: John Williams] #261646
07/24/13 07:55 AM
07/24/13 07:55 AM
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Posts: 1,658
Florida Suncoast, Dunedin Caus...
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Originally Posted by John Williams
I've taken some private flak for picking NZL early; I hope some of the folks who may be bent at my surety realize that, not only do I believe that they have the fastest boat upon the sea (tip o' the hat, Cap'n Nat), but I also feel some national pride in the work done by Nat Shaver, Bobby Kleinschmit and Pete Melvin, all members of my Club, who picked up sticks to live in New Zealand for over two years to get to this point. Hat's off.


Darren Bundocks comment,

Oracle is getting prepared for the Final, and seeing the Kiwis races, I'm glad OR has a two boat test to keep pushing the limits, TNZ is fast, Oracle looks even quicker , but how much faster can you go?
Will find out soon, but I'm sure beyond speed diff , if any, we will see some incredible Matches between them.



Have Fun
Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261647
07/24/13 07:58 AM
07/24/13 07:58 AM
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Posts: 2,490
On the Water
P.M. Offline OP
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Ben Ainslie reflects back on that tragic day.

"And in the middle of one of the bear aways we got a sharp gust at just the wrong angle. We didn’t wipe out but it was a hairy moment. I was thinking, ‘What am I doing here?’ I was thinking about Bart.”

To tell your grandkids, ‘I was there with Jess Ennis or Mo Farah at the closing ceremony’.”

With typical modesty, Ainslie neglects to mention that he was chosen to carry Team GB’s flag in the Olympic Stadium that night."


[Linked Image]


Philip
USA #1006
Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261648
07/24/13 08:06 AM
07/24/13 08:06 AM
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Philip
USA #1006
Re: AC72 Oracle Team USA Spaceship has landed [Re: northsea junkie] #261650
07/24/13 08:17 AM
07/24/13 08:17 AM
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Originally Posted by northsea junkie
I think something is lost in the translation and/or the transmission of this remark.

Look, apparent wind is the resultant of the true wind in the sail and the boatspeed in opposite direction. The last is derived from the so-called groundspeed.

So, when the current is with you, your groundspeed will be higher then in the situation when the current is against you.


I think the foils add more complexity to the equation.
The speed at which an AC72 starts foiling is determined by the speed through the water (23kts?).
So to reach the same speed through the water you would need to sail quicker over ground than if you where sailing against the current right? (Maybe 3kts or so).

Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261651
07/24/13 08:34 AM
07/24/13 08:34 AM
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Greenville SC
bacho Offline
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That makes sense at lower wind ranges where foiling may be borderline. Yesterday the comment was made that ETNZ was using it to their advantage at 35-38kts. It would seem to me that if they were already traveling those speeds then the adverse current is only extra drag. I am no expert though, nor did I stay at the holiday inn last night.

Re: AC72 Oracle Team USA Spaceship has landed [Re: brucat] #261652
07/24/13 08:35 AM
07/24/13 08:35 AM
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South Carolina
Jake Offline
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The less windspeed comment does make sense. As the water moves at 3 knots in the same direction as the wind, it's just like having 3 knots less wind. Consider your car on a conveyor belt. If the wind was 10mph and you are driving into it at 10 mph, you would normally experience 20mph of apparent wind. If your car was now on a conveyor belt that was moving 10mph in the opposite direction (so your car is now not making any forward progress), the apparent wind would be only 10.

It doesn't matter foiling or not - the speed vector of the water current that is parallel to the wind directly subtracts (or adds!) to the wind speed.


Jake Kohl
Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261653
07/24/13 08:57 AM
07/24/13 08:57 AM
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Sebring, Florida.
Timbo Offline
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OR...perhaps TNZ was so far ahead, they were just 'testing the waters' i.e. they took the opportunity to do some on course speed testing, to see if one side of the course was heavily favored with that current/wind combination, so if they run into that same combo in the finals, they'll already know the answer to the age old question at the top mark;

"Right or Left?"


Blade F16
#777
Re: AC72 Oracle Team USA Spaceship has landed [Re: Timbo] #261654
07/24/13 09:06 AM
07/24/13 09:06 AM
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Clermont, FL, USA
David Ingram Offline
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Originally Posted by Timbo
OR...perhaps TNZ was so far ahead, they were just 'testing the waters' i.e. they took the opportunity to do some on course speed testing, to see if one side of the course was heavily favored with that current/wind combination, so if they run into that same combo in the finals, they'll already know the answer to the age old question at the top mark;

"Right or Left?"


I'm quite confident these guys knew exactly where they were going and why. The effect of current on VMG is something they got sorted out long ago.


David Ingram
F18 USA 242
http://www.solarwind.solar

"Do or do not. There is no try." - Yoda
"Excuses are the tools of the weak and incompetent" - Two sista's I overheard in the hall
"You don't have to be a brain surgeon to be a complete idiot, but it helps"
Re: AC72 Oracle Team USA Spaceship has landed [Re: Jake] #261656
07/24/13 10:17 AM
07/24/13 10:17 AM
Joined: Sep 2002
Posts: 3,224
Roanoke Island ,N.C.
Team_Cat_Fever Offline
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Originally Posted by Jake
The less windspeed comment does make sense. As the water moves at 3 knots in the same direction as the wind, it's just like having 3 knots less wind. Consider your car on a conveyor belt. If the wind was 10mph and you are driving into it at 10 mph, you would normally experience 20mph of apparent wind. If your car was now on a conveyor belt that was moving 10mph in the opposite direction (so your car is now not making any forward progress), the apparent wind would be only 10.

It doesn't matter foiling or not - the speed vector of the water current that is parallel to the wind directly subtracts (or adds!) to the wind speed.


The foiling side of it is to get the lift, to free up hull drag. Which creates less effort on the sails/wing to move the boat faster.More flow over the foils increases lift ,but would also increase drag. The light air basis of the original statement may have some merit, but since SF is not known for light air (to the contrary) I don't think it pertains here. As your speed increases ( due to wind or current)so does your apparent wind. Don't let these non-multihull sailing commentators scramble your brain with their babble. All of you guys know better.


"I said, now, I said ,pay attention boy!"

The cure for anything is salt water - sweat, tears, or the sea
Isak Dinesen
If a man is to be obsessed by something.... I suppose a boat is as good as anything... perhaps a bit better than most.
E. B. White
Re: AC72 Oracle Team USA Spaceship has landed [Re: Team_Cat_Fever] #261657
07/24/13 10:33 AM
07/24/13 10:33 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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Jake  Offline
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Originally Posted by Team_Cat_Fever
Originally Posted by Jake
The less windspeed comment does make sense. As the water moves at 3 knots in the same direction as the wind, it's just like having 3 knots less wind. Consider your car on a conveyor belt. If the wind was 10mph and you are driving into it at 10 mph, you would normally experience 20mph of apparent wind. If your car was now on a conveyor belt that was moving 10mph in the opposite direction (so your car is now not making any forward progress), the apparent wind would be only 10.

It doesn't matter foiling or not - the speed vector of the water current that is parallel to the wind directly subtracts (or adds!) to the wind speed.


The foiling side of it is to get the lift, to free up hull drag. Which creates less effort on the sails/wing to move the boat faster.More flow over the foils increases lift ,but would also increase drag. The light air basis of the original statement may have some merit, but since SF is not known for light air (to the contrary) I don't think it pertains here. As your speed increases ( due to wind or current)so does your apparent wind. Don't let these non-multihull sailing commentators scramble your brain with their babble. All of you guys know better.


Hmmm...I'm not sure that the water still isn't the largest resistance to the boat speed even on foils...but I'll have to ponder that.


Jake Kohl
Re: AC72 Oracle Team USA Spaceship has landed [Re: P.M.] #261663
07/24/13 11:48 AM
07/24/13 11:48 AM
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Roanoke Island ,N.C.
Team_Cat_Fever Offline
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I'd have to guess aero drag is bigger once on foils.


"I said, now, I said ,pay attention boy!"

The cure for anything is salt water - sweat, tears, or the sea
Isak Dinesen
If a man is to be obsessed by something.... I suppose a boat is as good as anything... perhaps a bit better than most.
E. B. White
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