Salty Seacock

Emirates Team New Zealand.

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11 hours ago, Horn Rock said:

Does anyone own a video camera in Cagliari? Lots of pretty stills, but sweet fuck all video of the hand bag boat in motion.

Not to worry, Jimbo the turd and his ruthless cougar hunters will be in Auckland soon. They'll be plowing westie solo-mums and the Hauraki Gulf up under the watchful lens of our hero videographer @weta27 soon, (The sailing, not the solo-mum stuff).

Now, look at this.

 

 

images (3).jpeg

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15 hours ago, Hawke said:

are you saying that the challenge of getting the boat to fly at low airspeeds means "supercavitation" can't be used?

I wasn't referring to true supercavitation.  I did read some research that partial cavitation up to a certain point has some advantages.

Partial cavitation is draggy as heck & unstable.

The bubble essentially counts as extra fatness of the foil -> much more drag.

In transition you get unstable separation point and funky stuff at reattachment point including damage to the foil surface from bubble implosion & can cause resonant oscillation damage.

 

Traditionally that is resolved by going to a wedge shaped foil that intentionally initiates a clean cavitation at the leading edge eg on high-speed propellers but its obviously a very inefficient shape at sub-cavitation speeds

 

Foil-flow-regimes-From-sub-to-supercavti

There have been various attempts to create some kind of hybrid that cavitates cleanly but can operate reasonably efficiently sub-cavitation but not sure if any have proven to work as intended.

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8 minutes ago, Hawke said:

What about the OK-2003 experimental foil?

Interesting but counts as unproven unless you know of some racers using it successfully?

I'd also question the efficiency of that shape at low speeds.

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2 hours ago, Forourselves said:

Well, I guess the data analysts and recon teams are obsolete now. We have @The_Alchemist who can tell us exactly how fast each team is in any given condition simply by dissecting a few YT videos and measuring the Frames and time it takes for a boat to get from one point to another in the video. 5G who needs it? Data logging? Nah, SA is where it’s at lol

You are such a fckg idiot.  It is a very simple calculation, most kids learn it in junior high school.....  you will get to it in a few years...

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2 hours ago, JALhazmat said:

How fast is this? 

Obviously, you do not listen to anything.  The camera pans, is pixelated and the object is not traveling perpendicular to the camera....  

It is hard to fix stupid!

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3 hours ago, Ex-yachtie said:

Seagull - 2:09. Have at it. 
 

On another note, interesting to see the crew movement in the manoeuvres. Two crew move to windward (helm and main?) and one to leeward (foils?). They look very relaxed in the gybe, c.1:45

I noticed that a month ago with the little boat...they are always doing the"no look" manoeuvre. No more running the "I'm gonna tack" flag up 10 seconds before they go. I'm talking all the scurrying across the tramp. Should make for more interesting racing.

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3 hours ago, Forourselves said:

Well, I guess the data analysts and recon teams are obsolete now. We have @The_Alchemist who can tell us exactly how fast each team is in any given condition simply by dissecting a few YT videos and measuring the Frames and time it takes for a boat to get from one point to another in the video. 5G who needs it? Data logging? Nah, SA is where it’s at lol

Here is some homework...  Let me know if you need a lesson on Fractions to help you understand this session on speed:

 

 

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2 hours ago, The_Alchemist said:

Here is some homework...  Let me know if you need a lesson on Fractions to help you understand this session on speed:

 

 

Far from accurate and doesn’t account for variables so in other words... useless, like you and your team.

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On 7/16/2020 at 10:59 PM, Boink said:

Your response is both Non Sensical and Contradictory.

So you want Extreme BUT you also want Stability.

This is the old Doug Lord school of thinking. One Foil to do everything - early take off (@ 3.5 or 4 Knots of TWS) AND and yet be high performance (+50 Knots Boat Speed)

I recall he was also dreaming of boats capable of armchair sailing, yet foiling, yet ultra fast........ This is the America's Cup - Not Geriatrics with Dementia Boating Trips Inc. Ltd.

Your comment As a sailor a good boat is a boat with some basic stability, alienates every Moth and Kite Foil sailor out there. 49er and I14 sailors would also take issue. In fact most high performance sailboat sailors would understand that you are talking nonsense.

You love of multihulls is not exactly Top Secret, but your commentary on anything that is not Multihull is just old. 

Your comment 1) the first Verdier version, with a small center weight or keel, but it is true it would have been slower, is describing that the America's Cup should be run in the YAC9F boats - and we have seen how relatively docile thay are compared to the AC75's or Testing Mules...... Just because you will never have the talent or skills to sail an AC75 does not make them an invalid proposition. 

This is like asking Formula 1 to be run in Saloon Cars or MotoGP to be run on 50cc scooters. That is complete Nonsense.

So as I previously said - when you have a new class of high performance and on the edge type of boats - and they are learning how to sail them and push them really hard, do not confuse a Boat handling error that leads to a bit of a slash down (that gets #Clown Pa all foaming at the mouth) or worse a capsize, with being grounds to condemn a boat type.

^^ Pathetic boinkboink, we could agree or not with Doug Lord but at least is was structured, nothing close to your senseless rants.

If we follow your logic a boat with less stability  should be faster, then a moth, 49er or an opti should be faster than an F50 ? Idiot. You compare monos with multis, fallacious argument.  A fast boat does not have to be unstable in light wind, but driven to the limits to be fast.

Where did I say that the AC75 should be run against YAC9F for kids, were you drunk or trolling ? 

Then you tell that the AC75 capsizes were due to boat handling errors, but they were sailed by PB and JS in light or medium conditions. Even if they may have made mistakes it tells that the boat is inherently unstable.

Keep untertaining us clown :)

 

 

 

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On 7/17/2020 at 12:01 AM, Boink said:

The reality is that once airbourne, performance is more limited by induced drag, not just of both the hydrofoils and rig than by the power output, but also of the whole package. That is why Ineos is such a weird shape, the bustle of ETNZ and LR is a step forward (for multiple reasons) and why B1 of AM represents the laggard of the pack.

So, you realize 7 years later that drag is key, keep up mate. :)

As for your second point, could you explain the "multiples reasons" why AM represent the laggard of the pack and what makes you tell that the TNZ, LR and IneosB2 will be like the B1 you mention ?

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5 hours ago, The_Alchemist said:

Obviously, you do not listen to anything.  The camera pans, is pixelated and the object is not traveling perpendicular to the camera....  

It is hard to fix stupid!

Oh. Sorry, yet you can accurately measure a yacht filmed with a fucking massive zoom through a web cam  but cant work out the speed on that vid when they are no more that 150m at any point... 

as for vid quality, you were pretty fuckin sure of your self with the ineos vid.. 

try harder, or can’t we fix bullshit? 

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4 hours ago, JALhazmat said:

Oh. Sorry, yet you can accurately measure a yacht filmed with a fucking massive zoom through a web cam  but cant work out the speed on that vid when they are no more that 150m at any point... 

as for vid quality, you were pretty fuckin sure of your self with the ineos vid.. 

try harder, or can’t we fix bullshit? 

If you choose to mistrust @The_Alchemist's methodology, then just ignore the numbers he gives as bunk.

For me, I get how he calculates them and the degree of accuracy involved depending on the footage and camera angle... :-)

Do you get the parallel to a relatively still camera part? It makes analysis of the kite clip quite hard.

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17 hours ago, Guvacine said:

Yeah. Definitely can't see an AC50, F50 or AC72 staying with those numbers. Now I see why the spastic geckos were such a good idea and were worth the tremendous design and build investment.

Your tawdry sarcasm is noted ........ and dismissed!

Perhaps it escaped your notice that the Challenger mandated monhulls.

The Defender obliged.

FFS, stop flogging the dead horse, you dope!

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5 minutes ago, KiwiJoker said:

FFS, stop flogging the dead horse, you dope

It's called trolling...

Best cured by iggy. I've been procrastinating but shall do at once.

 

300px-Pseudointellectual_BS_degree.jpg

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On 7/17/2020 at 1:42 PM, Sea Breeze 74 said:

Why not challenge an F50 to an exhibition race sometime? Not sure where they're parked up but surely Core has at least one lying around somewhere :)

They're better off trying to beat ETNZ's AC50 first:blink:

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40 minutes ago, rh3000 said:

If you choose to mistrust @The_Alchemist's methodology, then just ignore the numbers he gives as bunk.

For me, I get how he calculates them and the degree of accuracy involved depending on the footage and camera angle... :-)

Do you get the parallel to a relatively still camera part? It makes analysis of the kite clip quite hard.

I get how he does it

i just do t get how he believes it’s accurate given the huge variables.

based on all his figures Every AC 75 boat Is slower than the kite in that clip.

I DO NOT buy that .

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5 hours ago, Indio said:

They're better off trying to beat ETNZ's AC50 first:blink:

If the defenders were confident in their new technology, an F50 / AC75 exhibition would have happened long ago. Imagine the excitement that such an event would generate. The fact that it has not happened, and that the Kiwi trolls on this thread are so defensive about such comparisons, shows that their is more anxiety than real confidence about the dubious AC75 design.

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5 hours ago, barfy said:

It's called trolling...

Best cured by iggy. I've been procrastinating but shall do at once.

 

300px-Pseudointellectual_BS_degree.jpg

Wow - a man of action!

You do know that absolutely no one cares about your precious "iggy list" you continually drone on about?

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5 minutes ago, Guvacine said:

If the defenders were confident in their new technology, an F50 / AC75 exhibition would have happened long ago. Imagine the excitement that such an event would generate. The fact that it has not happened, and that the Kiwi trolls on this thread are so defensive about such comparisons, shows that their is more anxiety than real confidence about the dubious AC75 design.

Even if you put up the millions of dosh for such an event it would never happen because it would be a distraction from their primary aim which is to win the AC.

On top of that no one has built their race boats yet so it could not happen.

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@Guvacine As said above, you want to take a race boat thee as is currently stripped and nailed to a wall and race it competitively against a first go of a new design series? 
 

unless you invent time travel how the fuck would it have happened AGES ago? 
 

the final race boat isn’t finished and the last events final boat had foils on the verge of failure and is stuck on a wall. Sounds like a shit race. 

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4 hours ago, Guvacine said:

If the defenders were confident in their new technology, an F50 / AC75 exhibition would have happened long ago. Imagine the excitement that such an event would generate. The fact that it has not happened, and that the Kiwi trolls on this thread are so defensive about such comparisons, shows that their is more anxiety than real confidence about the dubious AC75 design.

STFU troll. these boats are designed to win the America’s Cup, not some stupid one off exhibition race. The F50 is irrelevant. SailGP is irrelevant. The AC is the pinnacle of professional sailing. SailGP is for the second place competitors to compete against each other and pretend to be the best lol

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5 minutes ago, Ex-yachtie said:

Fuel for the fire. 
 

 

The test boat video seems accelerated, no seagull but the motor boat seems to go too fast. And even is the test boat could be faster it would not be of 30%.

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3 minutes ago, Tornado-Cat said:

The test boat video seems accelerated, no seagull but the motor boat seems to go too fast. And even is the test boat could be faster it would not be of 30%.

Read the notes under the video.

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9 hours ago, JALhazmat said:

I get how he does it

i just do t get how he believes it’s accurate given the huge variables.

based on all his figures Every AC 75 boat Is slower than the kite in that clip.

I DO NOT buy that .

There are no "HUGE" variables!  The boat does not change size, the videos are all filmed at consistent frames/second.  It doesn't matter how much the camera is zoomed.  

Remember, races are won by VMG and the ability to stay on the foils during clean maneuvers.  The crews are learning how to sail the boat most effectively, not win a drag race.  Go back and look at the AC50's in Bermuda, a lot of time was spent in the mid 20 to upper 30 knots.

We have measured a few speeds in excess of 40 knots.  

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4 hours ago, Guvacine said:

If the defenders were confident in their new technology, an F50 / AC75 exhibition would have happened long ago. Imagine the excitement that such an event would generate. The fact that it has not happened, and that the Kiwi trolls on this thread are so defensive about such comparisons, shows that their is more anxiety than real confidence about the dubious AC75 design.

Which one would they use, one of Larry’s? Or the one hung on the side of their base as a reminder to all challengers of the thumping they got last time, stripped of gear for use on the AC75?

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14 minutes ago, Ex-yachtie said:

Fuel for the fire. 
 

 

Had to compare because of changes in conditions, but I do think the test boat is a better design.

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26 minutes ago, The_Alchemist said:

Had to compare because of changes in conditions, but I do think the test boat is a better design.

Had to compare or HARD to compare? Or just not comparable ? 

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15 minutes ago, Hawke said:

Why bother comparing when they are not going to race each other?!

You could say that about supermodels too. 

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1 hour ago, Ex-yachtie said:

Fuel for the fire. 
 

 

NO discusses the new boats from about 31 minutes in this. He believes Te Kahu could go head to head with Te Aihe.

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On 7/17/2020 at 8:58 AM, Guvacine said:

Oh I don't know. An AC50, or any multi developed with half of the funds spent on the spastic gecko.

Cats are shit for match racing. Go watch the F50s if you want to watch multis.

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Posted (edited)

Maybe TeKahu can race one of the F50s stashed at Warkworth. That's where they all are.  Nathan can drive the 50. 

If they let him in. Else find some kiwis.   

Edited by NeedAClew
Forgot quarantine

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23 minutes ago, NeedAClew said:

Maybe TeKahu can race one of the F50s stashed at Warkworth. That's where they all are.  Nathan can drive the 50. 

If they let him in. Else find some kiwis.   

You’re right. Larry should get them out training next to ETNZ, just to show how superior the F50s are. He knows where they are, most week days. 

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Good job on your speed-estimating efforts, Alchemist. Fun stuff, good contributions.

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4 hours ago, Sea Breeze 74 said:

NO discusses the new boats from about 31 minutes in this. He believes Te Kahu could go head to head with Te Aihe.

Very interesting observations by Nathan.  

The complexity of the boats require that they be taken out of the water every night so they have to drop the mast to put it in the base.  He thinks it takes more time to put the AC75 in the water and get it ready than it took to get the AC45 ready in Bermuda. (So much for the advantages of a soft sail).  Also, with foiling, you don’t necessarily gain speed by having a larger boat.  He compared the progress on the AC 75 to the AC 72 in SF.  Both were developing a new concept of boat that really took another AC cycle to get to more optimized performance.

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3 minutes ago, The_Alchemist said:

Very interesting observations by Nathan.  

The complexity of the boats require that they be taken out of the water every night so they have to drop the mast to put it in the base.  He thinks it takes more time to put the AC75 in the water and get it ready than it took to get the AC45 ready in Bermuda. (So much for the advantages of a soft sail).  Also, with foiling, you don’t necessarily gain speed by having a larger boat.  He compared the progress on the AC 75 to the AC 72 in SF.  Both were developing a new concept of boat that really took another AC cycle to get to more optimized performance.

He also wishes he was on the inside so he could see the pinnacle of sailing in action...

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6 minutes ago, The_Alchemist said:

Very interesting observations by Nathan.  

The complexity of the boats require that they be taken out of the water every night so they have to drop the mast to put it in the base.  He thinks it takes more time to put the AC75 in the water and get it ready than it took to get the AC45 ready in Bermuda. (So much for the advantages of a soft sail).  Also, with foiling, you don’t necessarily gain speed by having a larger boat.  He compared the progress on the AC 75 to the AC 72 in SF.  Both were developing a new concept of boat that really took another AC cycle to get to more optimized performance.

Boats are craned in and out all the time. It was the wing that was the complex issue of launch. A bigger boat definitely suits the AC better than a smaller boat. 

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7 hours ago, Sea Breeze 74 said:

NO discusses the new boats from about 31 minutes in this. He believes Te Kahu could go head to head with Te Aihe.

I would think that's Te Kahu's intended purpose all along.

Try out all the new ideas on Te Kahu because of the cost savings and if they provide the gains being sought after, implement them on Te Aihe, then modify Te Kahu with the next good idea, transfer to Te Aihe and so on.

With Te Kahu, you have an unlimited set of foil sets you can test, while Te Aihe remains the constant.

The sailing team easily has enough depth to sail both boats against each other. What better way to sharpen your match racing skills than against a more nimble opponent that's possibly just as fast?

ETNZ are masters of hiding shit in plain sight... 

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On 7/18/2020 at 12:13 PM, Tornado-Cat said:

So, you realize 7 years later that drag is key, keep up mate. :)

As for your second point, could you explain the "multiples reasons" why AM represent the laggard of the pack and what makes you tell that the TNZ, LR and IneosB2 will be like the B1 you mention ?

Firstly, it's an oxymoron for the retard at the back, to ask others to keep up.......

Secondly, No. Look up my previous posts, you lazy git.......

Lastly, ask a question that relates to the post's content directly, and not some twisted, out of context, rambling riddle of your own, to which I will never answer...... Because no one other than yourself, can comprehend what on earth you are babbling about.

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2 hours ago, The_Alchemist said:

Very interesting observations by Nathan.  

The complexity of the boats require that they be taken out of the water every night so they have to drop the mast to put it in the base.  He thinks it takes more time to put the AC75 in the water and get it ready than it took to get the AC45 ready in Bermuda. (So much for the advantages of a soft sail).  Also, with foiling, you don’t necessarily gain speed by having a larger boat.  He compared the progress on the AC 75 to the AC 72 in SF.  Both were developing a new concept of boat that really took another AC cycle to get to more optimized performance.

Even today, around the same 1.2-1.5 mile windward-leeward race course, there would not be a lot of classes faster than a Moth. Likely an AC72, an AC/Sail GP50 and an AC75, but you'd start to struggle to find much after that...

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2 hours ago, NZL3481 said:

Even today, around the same 1.2-1.5 mile windward-leeward race course, there would not be a lot of classes faster than a Moth. Likely an AC72, an AC/Sail GP50 and an AC75, but you'd start to struggle to find much after that...

Kite board kicks a moths ass

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^ and it's because of extreme cant. Just like the new AC class can strut.

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3 hours ago, NZL3481 said:

I would think that's Te Kahu's intended purpose all along.

Try out all the new ideas on Te Kahu because of the cost savings and if they provide the gains being sought after, implement them on Te Aihe, then modify Te Kahu with the next good idea, transfer to Te Aihe and so on.

With Te Kahu, you have an unlimited set of foil sets you can test, while Te Aihe remains the constant.

The sailing team easily has enough depth to sail both boats against each other. What better way to sharpen your match racing skills than against a more nimble opponent that's possibly just as fast?

ETNZ are masters of hiding shit in plain sight... 

Etnz are the merry tricksters. I was surprised to see b1 in the water again after all the gains that Te Kahu demonstrated. Maybe b2 is not gonna show its face until October. I would think it's ok to show your hull soon,  as there is no way to Xerox..unless of course you glue on a keel.

Edit: I'll be wrong again perhaps but I reckon Te Kahu is on the shelf

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11 hours ago, The_Alchemist said:

There are no "HUGE" variables!  The boat does not change size, the videos are all filmed at consistent frames/second.  It doesn't matter how much the camera is zoomed.

FWIW video can and does change frames/second when re-encoded and uploaded, frames are interpolated as a matter of course by the algorithms involved.

The boat also changes size in comparison with the background, due to the depth of field of the lens, no camera lens is ever a true representation of the scene in front of it and distorts the image it receives. If you've ever seen GoPro (or other fisheye lens) footage you'll know what I mean but it is present to some degree in all lenses. Any photographer would be able to tell you this, its one of the reasons you have a variety of fixed focal length and variable focal length lenses available.

Your technique is a fun way to guess at these boats speeds and changes, but you're missing some variables (and raw footage) to make any accurate comparisons... 

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1 hour ago, barfy said:

^ and it's because of extreme cant. Just like the new AC class can strut.

Yup and less drag (hydro) aero is an issue given kite size but also way more power can be produced too.

 

they race kite vs moth at the Portsmouth ACWS event  a few years back there was a danger of lapping, it was so one sided 

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6 minutes ago, JALhazmat said:

Yup and less drag (hydro) aero is an issue given kite size but also way more power can be produced too.

 

they race kite vs moth at the Portsmouth ACWS event  a few years back there was a danger of lapping, it was so one sided 

And I don't mean to dis the folks that can race the moth machine..Just seems this time the KISS principle yields gains on the track.

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6 hours ago, JonRowe said:

FWIW video can and does change frames/second when re-encoded and uploaded, frames are interpolated as a matter of course by the algorithms involved.

The boat also changes size in comparison with the background, due to the depth of field of the lens, no camera lens is ever a true representation of the scene in front of it and distorts the image it receives. If you've ever seen GoPro (or other fisheye lens) footage you'll know what I mean but it is present to some degree in all lenses. Any photographer would be able to tell you this, its one of the reasons you have a variety of fixed focal length and variable focal length lenses available.

Your technique is a fun way to guess at these boats speeds and changes, but you're missing some variables (and raw footage) to make any accurate comparisons... 

Sorry, but I check the frame rate at each of the measurements to make sure I use the correct times.   The changes in depth of field really doesn't matter as long as it is consistent for the 1-2 seconds that the measurement is taken.  I only use the size of the boat and not the size of any other object.  And by the way, I am a photographer that sells images on Getty Images, so I may have more invested in cameras/lens than you have in your car.  

Again, it is not rocket science.  Notice that I only calculate the speed at very specific spots in the videos where I can get the right conditions to get the best measurements.

I have always said that I estimate my error to be a couple of knots.  I only show the numbers to a tenth of a knot to indicates the relative difference in the numbers (so 27.4 was faster than 26.5).

Like rh3000 said, if you do not believe my calculations, then just ignore them. 

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19 hours ago, Ex-yachtie said:

Fuel for the fire. 
 

 

This forum must be a never ending supply of humour for the people that are involved in the AC.

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35 minutes ago, The_Alchemist said:

Sorry, but I check the frame rate at each of the measurements to make sure I use the correct times. The changes in depth of field really doesn't matter as long as it is consistent for the 1-2 seconds that the measurement is taken.  I only use the size of the boat and not the size of any other object. 

Thats my point, you don't have the correct times, you have the output times from a unknown compression algorithm. The changes in depth of field do matter because you no longer know the size of the boat, you don't know if it's appearing compressed compared to its actual size at that distance, so even if your timing was accurate, the distance isn't, especially considering you don't have exactly 90degrees.

Like I say fun game, probably more than a few knots out.

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12 hours ago, NZL3481 said:

ETNZ are masters of hiding shit in plain sight... 

Like allegedly pocketing public money.

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40 minutes ago, JonRowe said:

Thats my point, you don't have the correct times, you have the output times from a unknown compression algorithm. The changes in depth of field do matter because you no longer know the size of the boat, you don't know if it's appearing compressed compared to its actual size at that distance, so even if your timing was accurate, the distance isn't, especially considering you don't have exactly 90degrees.

Like I say fun game, probably more than a few knots out.

No sorry you are wrong. As you said yourself the footage gets interpolated by YouTube so that footage doesn’t change speed only the playback of that footage maybe Interpolated in NTSC rather than PAL. Otherwise we would hear weird audio if anyone uploaded something at 25fps

Depth of field also doesn’t change the size of things, just how much is in focus. At that distance focal length compresses perspective so that is not really an issue either.

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What matters how close the landmark is from the boat. With precise measure of the time  the Alchemist can get a pretty precise idea of the speed. VMG is another question. As for the kite it made no sense to bring it as the length is too short and there was no close landmark.

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Given that any landmark in All of the vids that have been speed assessed are a totally unknown distance from the boat kinda fucks your argument..

also stating speeds over a 1-2 second duration tells you virtually nothing. Acceleration, deceleration are left unaccounted for.

you could  do the same with a formula1 car and get a speed answer from say 30-200mph is it braking accelerating? Going through a corner? Etc 
 

it just means that at that specific moment in time is was doing X speed, and that is a lousy assessment of performance, it’s certainly irrelevant in terms of trying to compare performance of different boats sailed in different locations and conditions. 
 

the lemmings following it as gospel is plain stupidity. 
 

yes it’s lovely to show that you like messing with video and doing maths but that really is all it is.

if it wasn’t you would be working for a team not posting here. 

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1 hour ago, JALhazmat said:

it just means that at that specific moment in time is was doing X speed

So what? It’s much better than simply guessing. :)

Am not getting the reason some folks feel defensive about the approximates being posted, since as you say there’s a lot else going on too. 
 

Some folks had a blast trying to calculate speeds of the AC72’s on SF Bay, it was great fun. 

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2 hours ago, Stingray~ said:

So what? It’s much better than simply guessing. :)

Am not getting the reason some folks feel defensive about the approximates being posted, since as you say there’s a lot else going on too. 
 

Some folks had a blast trying to calculate speeds of the AC72’s on SF Bay, it was great fun. 

I wonder if they’d do the same for an F50 and call those “accurate speeds”?

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1 hour ago, Forourselves said:

I wonder if they’d do the same for an F50 and call those “accurate speeds”?

Why are you guys so insecure about the AC75? It's your baby, you should love it....

ccc4a9bd-5824-47a8-ade2-8158164b3765-m.j

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On 7/19/2020 at 8:52 AM, Ex-yachtie said:

Fuel for the fire. 
 

 

Where was this taken from, Bastion Point?

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8 hours ago, The_Alchemist said:

Sorry, but I check the frame rate at each of the measurements to make sure I use the correct times.   The changes in depth of field really doesn't matter as long as it is consistent for the 1-2 seconds that the measurement is taken.  I only use the size of the boat and not the size of any other object.  And by the way, I am a photographer that sells images on Getty Images, so I may have more invested in cameras/lens than you have in your car.  

Again, it is not rocket science.  Notice that I only calculate the speed at very specific spots in the videos where I can get the right conditions to get the best measurements.

I have always said that I estimate my error to be a couple of knots.  I only show the numbers to a tenth of a knot to indicates the relative difference in the numbers (so 27.4 was faster than 26.5).

Like rh3000 said, if you do not believe my calculations, then just ignore them. 

I for one really appreciate your work; we all understand it's guesswork but at least it's honest and thought out guess work.  It is 100% better than "our team is doing great because it's our team and every one else sucks and if they don't they're cheating" 

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 If you are working on another team and having to watch this, how do you not want to start updating your resume...

 

There's a lot wrong in the world right now, but the control of the NZ boat is definitely not on the list.  Tacks, gybes all look like a dinghy. The bearaways I assume are especially freaky but they just look like they can chuck it down at will. No idea why but I'm always nervous on the bearaway with fast boats but they look no-sweat here.

 

Too soon to think about the next cycle held in NZ?

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18 minutes ago, RMac said:

 If you are working on another team and having to watch this, how do you not want to start updating your resume...

 

There's a lot wrong in the world right now, but the control of the NZ boat is definitely not on the list.  Tacks, gybes all look like a dinghy. The bearaways I assume are especially freaky but they just look like they can chuck it down at will. No idea why but I'm always nervous on the bearaway with fast boats but they look no-sweat here.

 

Too soon to think about the next cycle held in NZ?

Yes! Eyes on the job. 

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On 7/13/2020 at 12:12 AM, Ex-yachtie said:

Looks slow here. 
 

 

Seems like they have the boat handling down. I hope all the teams will in time. Then the event will be based on speed. I also guess that they are getting very good data about the crossover between delta and straight foils, and probably a lot of other things!

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5 hours ago, Forourselves said:

I wonder if they’d do the same for an F50 and call those “accurate speeds”?

No need to since SailGP records and displays “accurate speeds” and more, in great abundance! 
 

As to the expressed worries about informed AC75 speed guesses posted here being any concern to teams, get real: The teams have so much on each other that, as we have heard them explain, they can and do even run their competitors’ boats in simulators.  

 

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9 hours ago, JALhazmat said:

Given that any landmark in All of the vids that have been speed assessed are a totally unknown distance from the boat kinda fucks your argument..

also stating speeds over a 1-2 second duration tells you virtually nothing. Acceleration, deceleration are left unaccounted for.

you could  do the same with a formula1 car and get a speed answer from say 30-200mph is it braking accelerating? Going through a corner? Etc 
 

it just means that at that specific moment in time is was doing X speed, and that is a lousy assessment of performance, it’s certainly irrelevant in terms of trying to compare performance of different boats sailed in different locations and conditions. 
 

the lemmings following it as gospel is plain stupidity. 
 

yes it’s lovely to show that you like messing with video and doing maths but that really is all it is.

if it wasn’t you would be working for a team not posting here. 

It is utterly amazing that you just do not understand a simple concept and keep trying to toss in variables that are irrelevant.   If the camera remains stationary during the reading, it doesn't really matter what the distances are from the boat or the focal length of the lens.

Of course all of the readings are just a moment in time.  Who claimed it was anything different?  None of the teams have given us their data feed!  How much acceleration/deceleration do you think is taking place with these AC75's traveling in a straight line over 1-2 seconds?  I give a time stamp for each of the speed calculations and people are free to note what is happening to the boat, wind direction or water conditions at those moments.  Some points were taken right before or after maneuvers and some with both foils in the water. 

You may think it is nothing, but I think it adds a little more value than making arbitrary comments (i.e. "it looks fast", "much faster than blah, blah, blah...").  I think getting an idea of what the speed is interesting. 

Like we have said, you are free to ignore it, just like I will ignore anymore of your comments on it.  

We have wasted way too much time on this and it is not productive.

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11 hours ago, JonRowe said:

Thats my point, you don't have the correct times, you have the output times from a unknown compression algorithm. The changes in depth of field do matter because you no longer know the size of the boat, you don't know if it's appearing compressed compared to its actual size at that distance, so even if your timing was accurate, the distance isn't, especially considering you don't have exactly 90degrees.

Like I say fun game, probably more than a few knots out.

Wow, does the rules committee know that you can change the length of the boat by just using another depth of field?

The AC75 is always the same length during any specific sail.  The speed measurements do not take into account how much of the video frame is taken up by the boat (more if it is closer to the camera, or less if it is father away).  As I mentioned earlier, slight variations in the angle of the boat from perpendicular to the camera only give tenths of a knot errors in the speed.

These boats are moving fast and they move a significant amount in every frame of the videos.  There are times where I have calculated 3 or more readings right after another on the same run and they all give the same speed.  So I think my few knots estimate is fairly accurate.

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11 minutes ago, The_Alchemist said:

The AC75 is always the same length during any specific sail.

Well, that does depend on the speed. If it's going as fast as some KiWhingersTM claim - it could actually be contracting.

You know - relativity and all.

image.png.357dc053a5d07ebb26e44bc33beed31c.png

I'm sure one of them can explain it to you. Smart fellas.

Heh.

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11 hours ago, uflux said:

…Interpolated in NTSC rather than PAL.

I think standards for analog broadcast TV (add SECAM to the list) are irrelevant now. Digital terrestrial TV uses ATSC, DVB, ISDB or DTMB. In the digital media and online realm there are a number of basic digital compression algorithms and more than a dozen "standards" that cater for a virtually an infinite variety of frame rates.

I think The_Alchemist's methodology is sound for getting rough estimates, provided the frame rate is known and systematic errors aren't too large. What matters is that the camera and reference point are stable, the camera is a good distance from the boat so it doesn't fill too much of the field of view (minimising parallax and lens distortion errors) and the boat is travelling about 90º to the line from camera to reference point. It's effectively the same methodology as used by police amphometer speed traps until radar and laser systems were introduced.

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2 hours ago, bangbang said:

Seems the boys have been playing on the 49er

IMG_6052 2.jpg

Great to see Takakashi putting up a good fight!

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5 hours ago, Stingray~ said:

No need to since SailGP records and displays “accurate speeds” and more, in great abundance! 
 

As to the expressed worries about informed AC75 speed guesses posted here being any concern to teams, get real: The teams have so much on each other that, as we have heard them explain, they can and do even run their competitors’ boats in simulators.  

 

Remember when your “data” clearly showed Oracle were clearly the faster boat in Bermuda? 
Here is a fun experiment. Take a YT video of an AC50 during a race in Bermuda. Say ETNZ or Oracle, during the match, that way we know they’re racing in anger. Use the above extrapolation method discussed above, then compare the results to the accurate data displayed on screen, that should give you a margin for error for these extrapolation measurements. Apply that margin of error to the above measurements for the above videos of Te Aihe and you should get an even closer “estimate” right? 

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On 7/19/2020 at 4:12 PM, barfy said:

Kite board kicks a moths ass

 

On 7/19/2020 at 4:14 PM, barfy said:

^ and it's because of extreme cant. Just like the new AC class can strut.

How Dare You! How Very Dare You!

These Nefarious Devices show a complete lack of Stability - Therefore cannot possibly be Good, Fast or Safe! 

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^ I'll bet they are in the back paddock practicing luffing duels.

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15 hours ago, JALhazmat said:

it just means that at that specific moment in time is was doing X speed

Thats the fucking point!

 

6 hours ago, Stingray~ said:

No need to since SailGP records and displays “accurate speeds” and more, in great abundance! 

From recollection @The_Alchemist has previously compared his measurements with reported race data & confirmed reasonable accuracy.

 

Its always going to be a rough estimate but as he says its a more informed estimate than 'oh boy that looks fast'.

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On 7/19/2020 at 3:46 PM, NZL3481 said:

Even today, around the same 1.2-1.5 mile windward-leeward race course, there would not be a lot of classes faster than a Moth. Likely an AC72, an AC/Sail GP50 and an AC75, but you'd start to struggle to find much after that...

On 7/19/2020 at 6:12 PM, barfy said:

Kite board kicks a moths ass

So three unobtainable classes plus one (relatively) popular class makes four, which, given the hundreds of classes being sailed, probably counts as "not a lot". ;-)

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Te Kāhu is back out today. Last seen off North Head, hiding behind a port crane from my point of view.

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9 minutes ago, mikenz2 said:

Te Kāhu is back out today. Last seen off North Head, hiding behind a port crane from my point of view.

Pretty sure they're doing this to me deliberately :-)

IMG_20200721_093555~2-03.jpeg

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just setting up in the Channel and off North Head before heading out around behind Rangi.

Two bulbed foils up today? And LR and AM in close company.

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what are they going to do if they take both boats out and go different ways

would be fun to just tow them both all over the place with only 1 crewman on board for a couple of days

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1 hour ago, weta27 said:

just setting up in the Channel and off North Head before heading out around behind Rangi.

Two bulbed foils up today? And LR and AM in close company.

DSC_0845.jpg

On 7/19/2020 at 6:21 PM, barfy said:

Edit: I'll be wrong again perhaps but I reckon Te Kahu is on the shelf

The wet shelf. :D

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One more with a little bit of detail of foil flaps, rig and main

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3 minutes ago, weta27 said:

One more with a little bit of detail of foil flaps, rig and main…

Not much twist in the main, is this just a heave–to or tow out setup?

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Heave-to I would say; they had spent about 10 mins tootling around in displacement mode, then stopped here for a few minutes. They may have towed briefly just after that, up to Narrow Neck, it was hard to tell, but there was enough breeze to foil and from there they were definitely under sail as they headed out.

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I forget, have they sported those same bulbed foils before today? 
 

Since there’s no reason to go with bulbs as a Rule mass-restriction ‘cheater’ it’s interesting they are (now) testing them regardless on this boat regardless. 

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I've only seen them with bulbed on one side, since the first time on 7th of May.

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1 minute ago, weta27 said:

I've only seen them with bulbed on one side, since the first time on 7th of May.

Thanks as always, terrific fun for all of us

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