Emirates Team New Zealand.

[Boink 661]

16 hours ago, barfy said:

^ come on. You two are exemplary SA'ers, with fairly un biased technical treatise. 

Don't follow the rest of us down the rabbit hole please. 

Barfy, I would not place my position very high on Rob's Christmas Card list. In fact, I am certain, I don't even feature.......

Too coincidental; a similar but an afterthought type posting, to not be suspicious. Doesn't pass the sniff test imho.

[Apterix 91]

13 hours ago, The_Alchemist said:

If you look at the ventilating outer wing on AM it is not horizontal.    The anhedral foils are about 15 degrees off of flat, so if the arm is at 30 degrees then the wing is about 15 degrees from horizontal.  A T foils would be at 30 degrees.  

It looks like there is considerable deflection toward the tips of the thinner foils with the winglets on AM.  Under load these foils may end up having more of a "w" shape i.e. anhedral close to the foil arm, and dihedral towards the foil tips.  To me it looks like etnz foils may be stiffer, but may end up in more of dihdral shape under load.  I am splitting hairs a little, but it is worth contemplating shape of foils under load when thinking about the angle of the foils in relation to the water's surface.  

Re the crabbing behaviour of the boats when sailing to windward, I have wondered whether this is the result of a temporary increase in flap angle used to correct a reduction in vertical lift.  If this were the case it may not be a very efficient foil configuration.  In the same way flaps deployed on a plane to increase lift at low speeds on landing also slow the plane down.    

[JALhazmat 1,175]

The foils LOOK stiffer? 

jeez SA structural analysis has taken a huge leap on that one.. 

Can you draw a yellow line on it where it looks stiffer? 

[barfy 1,122]

2 hours ago, Apterix said:

lection toward the tips of the thinner foils with the winglets on AM.  Under load these foils may end up having more of a "w" shape i.e. anhedral close to the foil arm, and dihedral towards the foil tips.  To me it looks like etnz foils may be stiffer, but may end up in more of dihdral shape under load.  I am

Normally you're not so speculative. 

Do you have observations like underwater shots? 

2 hours ago, Apterix said:

Re the crabbing behaviour of the boats when sailing to windward, I have wondered whether this is the result of a temporary increase in flap angle used to correct a reduction in vertical lift.  If this were the case it may not be a very efficient foil configuration.  In the same way 

Really? Crabbing to windward will win you the race. These boats have been touted by the designers as being much faster around the track, that will be due to the "not be a very efficient foil design" with unlimited cant and lift to windward. Ffs

[Apterix 91]

1 hour ago, barfy said:

Normally you're not so speculative. 

Do you have observations like underwater shots? 

Really? Crabbing to windward will win you the race. These boats have been touted by the designers as being much faster around the track, that will be due to the "not be a very efficient foil design" with unlimited cant and lift to windward. Ffs

Fair call - my comments were based on what looks to be flapping on AM's port foil tip in the most recent Roger Mills video, a perception that AM has thinner foil tips that ETNZ, and an assumption that all teams foils flex to some extent.  Speculative yes, but I did say "looks like, "may", etc to imply uncertainty.  And, I may be wrong on all counts. 

Re the crabbing - yes sailing efficiently to windward is obviously a winning strategy.  But, I still reckon that the lurching to windward we see in many of the recent videos may be the result of the ride height trimmer applying more flap angle to achieve correct ride height and sudden lateral lift is a by-product.  I am not saying that the foils wont be set up to lift the boats to windward on upwind beats, but that more foil flap angle is likely to be accompanied by increased drag which may not be that efficient.  

[The_Alchemist 1,256]

7 hours ago, barfy said:

Normally you're not so speculative. 

Do you have observations like underwater shots? 

Really? Crabbing to windward will win you the race. These boats have been touted by the designers as being much faster around the track, that will be due to the "not be a very efficient foil design" with unlimited cant and lift to windward. Ffs

So, can we now just label the squirrelly sailing we have seen as crabbing to windward?

[P Flados 198]

For boats with centerline T Foils (moth, etc.) I have heard "crabbing to windward" used for where you have sufficient windward heel that the main foil is providing enough lateral forces such that the main foil strut is providing little or no lateral force. 

This is thought to greatly reduce drag at the 3 way junction (main foil to strut) and has been observed to be great for VMG. 

 

[Ex-yachtie 1,560]

Just in case there’s any kiwis lurking here. 
 

Spotted at Hobsonville this morning. Possibly running a ferry service due to the harbour bridge. 

[Priscilla 2,324]

 

[chesirecat 456]

6 hours ago, P Flados said:

For boats with centerline T Foils (moth, etc.) I have heard "crabbing to windward" used for where you have sufficient windward heel that the main foil is providing enough lateral forces such that the main foil strut is providing little or no lateral force. 

This is thought to greatly reduce drag at the 3 way junction (main foil to strut) and has been observed to be great for VMG. 

 

Not just foilers. Most centerboarders can do it. 

[fish7yu 477]

America's Cup: Get ready for a surprise, predicts Team New Zealand principal Matteo de Nora 

09:50, Sep 21 2020

America's Cup: Get ready for a surprise, predicts Team New Zealand principal Matteo de Nora

[mikenz2 1,536]

Te Aihe heading out with a Code 0 up, before furling it and going under tow out to Motukorea
 

 

[rh3000 1,612]

57 minutes ago, fish7yu said:

America's Cup: Get ready for a surprise, predicts Team New Zealand principal Matteo de Nora 

09:50, Sep 21 2020

America's Cup: Get ready for a surprise, predicts Team New Zealand principal Matteo de Nora

“They are fast, but not unstable especially when compared to those used in the America's Cup in the last 10 years,” de Nora told La Stampa.

“As we have seen recently, the teams were able to straighten the AC75s after the capsize without problems and resumed sailing immediately afterwards."

Very true. Remember all those accusations of these boats being dangerous pitch-polling monsters - looks like that theories went the way of those spouting them...

[barfy 1,122]

49 minutes ago, mikenz2 said:

Te Aihe heading out with a Code 0 up, before furling it and going under tow out to Motukorea

Thx! Looks like pretty good angle judging by when she luffed up to furl.

Did you see a tack?

[mikenz2 1,536]

15 minutes ago, barfy said:

Did you see a tack?

No, I assume they tacked just off Devonport but I missed it.

[RobG 753]

1 hour ago, fish7yu said:

America's Cup: Get ready for a surprise, predicts Team New Zealand principal Matteo de Nora 

09:50, Sep 21 2020

America's Cup: Get ready for a surprise, predicts Team New Zealand principal Matteo de Nora

'[de Nora] admitted it would have been “interesting” to have one or two more syndicates involved in the Prada Cup challenger series though he doubted they would have “increased the current technical value”'

Perhaps he's heard of the 80/20 rule, or the 90/90 rule.

[RobG 753]

On 9/20/2020 at 7:07 AM, accnick said:

Nonsense. Read the definition of AC 75 Class Yacht in the Protocol:

AC75 Class Yacht means a yacht that complies with or could comply with the AC75 Class Rule;

"Could comply" leaves it wide open to interpretation and might include yachts from 16 m to 25 m, even without foils, sails or mast that measure but given appropriate modifications could measure. The point is it's up to the MC to determine whether a boat is an AC75 or a surrogate, which is a reasonable approach given the difficulty of trying to define the difference exactly in words.

I don't think putting an asymmetric fitting on a foil for testing makes the boat a surrogate, but I can understand the argument from those who think it might. At the very least it means teams are allowed to sail AC75s that do not measure outside of official events.

[mako23 451]

3 hours ago, RobG said:

'[de Nora] admitted it would have been “interesting” to have one or two more syndicates involved in the Prada Cup challenger series though he doubted they would have “increased the current technical value”'

Perhaps he's heard of the 80/20 rule, or the 90/90 rule.

In a previous life I use to be programmer and 90/90 rule is so true. Major application takes one year to write ten years to debug. 

[WakaNZ 161]

On 9/18/2020 at 1:12 PM, Ex-yachtie said:

Shit, that’s laying it all on the table isn’t it?! 
 

Was the person who told you this equally definite in their description, or do you think they might have been bullshiting just to give the impression they knew what they were talking about?

Very reliable, how I knew about the mule (Te Kahu) and the Judges decision before either were public. 

[weta27 4,597]

New sponsor, new foil appendage?

[Varan 1,930]

what a beast. I love this cup

[WakaNZ 161]

27 minutes ago, weta27 said:

New sponsor, new foil appendage?

Themarket.com is a subsidiary of TWG ( The Warehouse Group ), Same owners of Torpedo7, Sir Stephan sharing the love across the retail brands.  

[Forourselves 1,161]

 

[Ex-yachtie 1,560]

2 hours ago, WakaNZ said:

Very reliable, how I knew about the mule (Te Kahu) and the Judges decision before either were public. 

Yeah, but you haven’t really told us anything, have you? It’s such a nondescript statement that anything would fit it. 

[Ex-yachtie 1,560]

1 hour ago, Forourselves said:

 

Wow. Sailing with the Code 0 is a real sight. Gybing looks worth avoiding though.  

[Sailbydate 2,584]

57 minutes ago, Ex-yachtie said:

Wow. Sailing with the Code 0 is a real sight. Gybing looks worth avoiding though.  

Except that's NOT a Code Zero sail, EX. Not even close.

Well, maybe a little close. More like a screecher.

Edited September 21, 2020 by Sailbydate
Explanation

[mako23 451]

2 hours ago, WakaNZ said:

Themarket.com is a subsidiary of TWG ( The Warehouse Group ), Same owners of Torpedo7, Sir Stephan sharing the love across the retail brands.  

 

3 hours ago, weta27 said:

New sponsor, new foil appendage?

Looks like a fence is being put on that wing, just like a old Soviet jet fighter 

 

 

[mikenz2 1,536]

Was an epic watching both of them out there today

[mikenz2 1,536]

 

[Ex-yachtie 1,560]

14 minutes ago, mikenz2 said:

 

I wonder if those tacks will EVER look normal?

[Ex-yachtie 1,560]

1 hour ago, Sailbydate said:

Except that's NOT a Code Zero sail, EX. Not even close.

Well, maybe a little close. More like a screecher.

Whatever, big fuck off sail from the bowsprit.

[weta27 4,597]

[Eiar 3]

Just had a crazy thought - what’s to stop having pilot Pete in a see through canopy in the bow of the boat  - would improve aero and complete the fighter analogy!

[NSP 190]

No crew allowed forward of the mast?  Not sure if that is actually in the class rule, but I vaguely remember it being mentioned at one point.

[hoom 576]

Also no cover above any of the crew except trivially briefly.

 

4 hours ago, weta27 said:

New sponsor, new foil appendage?

Did they lose some sponsors?

That mainsail looks a lot more bare than I remember.

Maybe just a re-arrangement of existing sponsor locations?

[mikenz2 1,536]

 

[weta27 4,597]

Thanks mikenz2, I saw them come back in up the harbour to base and against the backdrop of the port they looked to be hooting along

[mikenz2 1,536]

8 minutes ago, weta27 said:

Thanks mikenz2, I saw them come back in up the harbour to base and against the backdrop of the port they looked to be hooting along

They were! They were also hiding from me

 

[Ex-yachtie 1,560]

 

[fish7yu 477]

America`s Cup AC75 Yachts Te Aihe & Defiant Sailing in the same Patch Auckland - September 21, 2020

AUCKLAND NEW ZEALAND, September 21, 2020. The moment we have all been waiting for! Emirates Team New Zealand AC75 Yacht Te Aihe and American Magics Defiant out sailing on the Waitemata Harbour on the same day. Rules prevent them duelling but it was interesting to see how each yacht handled the light Easterly breeze

 

 

[Boink 661]

The little cruiser at 0.45 to 0.52 would have had the best seats in the house......

Look Honey!

Where?

There!

No There.....

And There!!!

Holy Sheeet.......!

See. I told you. I Need a Fasta Boat.......

[enigmatically2 758]

Well we can't tell whether they had the same wind or what they were trying to do, but when they are coming across on stbd tack from 1 minute to 2 minutes ETNZ was pointing fractionally but consistently higher (look at the shadow of the headsail on the main)

[The_Alchemist 1,256]

I see that NZ is now sailing with the tips of the foils out of the water at times.  They do not look as close to the water as when AM does it.

[Ex-yachtie 1,560]

12 hours ago, Sailbydate said:

Except that's NOT a Code Zero sail, EX. Not even close.

Well, maybe a little close. More like a screecher.

Looks like I’m not the only idiot. 

[weta27 4,597]

Thanks fish7yu and @airflownz, brilliant!

The crowds are in for a treat when these things line up in anger - grace with pace, and on a grand scale.

Seeing two of them together starts to hint at the spectacle.

[Sailbydate 2,584]

So what do you call a jib on a cable flown from a bow sprit?

Ha, ha. Yea. That old hoary chestnut.

I don't know. let's call it a Code Zero. And just to complicate things further, we have a cable-less Code Zero.

But as you say, EX, big fuck off sail from the bowsprit - that'll do me. ;-)

[Zeusproject 168]

Could be a BRO ( blast reaching o) 

could be a FRO (frac o ) 

But not a Code zero 

[TimmyHate 86]

1 hour ago, Sailbydate said:

 

But as you say, EX, big fuck off sail from the bowsprit - that'll do me. ;-)

The BFOS 

[Jethrow 137]

But Zeus, the o bit of the first two is actually zero so they're ALL zeros!

[Zeusproject 168]

15 minutes ago, Jethrow said:

But Zeus, the o bit of the first two is actually zero so they're ALL zeros!

Correct 

[Nodrog 42]

I'm probs late the party on this, as mentioned just above, the ETNZ boat now seems to be able to sail at will with the leeward part of the foil breaking the surface. I thought this ( and perhaps crossing a wake) was previously the point of doom, and triggered the wipe outs. Either way, they're looking mighty impressive. 

[Teaky 143]

On 9/16/2020 at 10:54 AM, Jono said:

OMG - Teaky's back!

Yo.

[Varan 1,930]

Crossings are going to be exciting. Photo from sail-world. 

[weta27 4,597]

Another one from yesterday

[trt131 182]

2 hours ago, Nodrog said:

I'm probs late the party on this, as mentioned just above, the ETNZ boat now seems to be able to sail at will with the leeward part of the foil breaking the surface. I thought this ( and perhaps crossing a wake) was previously the point of doom, and triggered the wipe outs. Either way, they're looking mighty impressive. 

AM have been doing it a lot also.

[fish7yu 477]

 

Emirates Team New Zealand: How to win races through the perfect design

 

 

[JALhazmat 1,175]

pass the sick bag for useless promo puff piece.

I mean thats the rest of the world reaction when Ineos trots it out.. luv n hugs x

[Sailbydate 2,584]

1 hour ago, JALhazmat said:

pass the sick bag for useless promo puff piece.

I mean thats the rest of the world reaction when Ineos trots it out.. luv n hugs x

Funny. I've been told, some people actually enjoy watching commercials and many are influenced by them. Who'd have thought, eh?

[Indio 893]

On 9/21/2020 at 12:45 PM, RobG said:

..At the very least it means teams are allowed to sail AC75s that do not measure outside of official events.

Teams have been doing that since  forever...

[barfy 1,122]

4 hours ago, JALhazmat said:

pass the sick bag for useless promo puff piece.

I mean thats the rest of the world reaction when Ineos trots it out.. luv n hugs x

A couple of shots of hooning out over pretty good chop.

[DickDastardly 233]

On 9/22/2020 at 7:56 AM, Teaky said:

Yo.

So exciting!

[pusslicker 285]

8 hours ago, JALhazmat said:

pass the sick bag for useless promo puff piece.

I mean thats the rest of the world reaction when Ineos trots it out.. luv n hugs x

You do have to enjoy how the Kiwi's can pivot from puff pieces being shit when Ineos does it to fucking the most amazing thing ever when ENTZ does it. These Kiwi fucks would make great politicians. Every last one of them in AC Anarchy.

[weta27 4,597]

Jealousy will get you nowhere ... 

[NZL3481 383]

On 9/17/2020 at 1:54 PM, The_Alchemist said:

Even if the bulb is less than 20% of the mass, the foil wings have changed considerably from the original two foils.  So NZ has used up at least 4 of their foils.  

Not necessarily...

[Offshore 1 23]

4 hours ago, pusslicker said:

You do have to enjoy how the Kiwi's can pivot from puff pieces being shit when Ineos does it to fucking the most amazing thing ever when ENTZ does it. These Kiwi fucks would make great politicians. Every last one of them in AC Anarchy.

COVID affects us all in different ways. If you need a hug just reach out

[JALhazmat 1,175]

On 9/17/2020 at 4:54 AM, The_Alchemist said:

Even if the bulb is less than 20% of the mass, the foil wings have changed considerably from the original two foils.  So NZ has used up at least 4 of their foils.  

It’s not about the bloody bulb!
 

anything that’s  in the box below the foil arm is subject to the 20% change by area, the change to area can only be accommodated within the 20% mass change. 
 

if making it 20% bigger (the foil assembly) is going to add more than 20% mass of the original then you can’t do it 

so getting tied up that the bulb has changed by 20% is a road to no where, as it’s the entire structure as a whole that you need to consider. 

[Forourselves 1,161]

4 hours ago, pusslicker said:

You do have to enjoy how the Kiwi's can pivot from puff pieces being shit when Ineos does it to fucking the most amazing thing ever when ENTZ does it. These Kiwi fucks would make great politicians. Every last one of them in AC Anarchy.

Aww cry me a river you fucking crybaby.

[Priscilla 2,324]

31 minutes ago, Forourselves said:

Aww cry me a river you fucking crybaby.

Crikey as erudite as ever at least you’re consistent.

[KiwiJoker 350]

5 hours ago, pusslicker said:

You do have to enjoy how the Kiwi's can pivot from puff pieces being shit when Ineos does it to fucking the most amazing thing ever when ENTZ does it. These Kiwi fucks would make great politicians. Every last one of them in AC Anarchy.

Yeah/nah!   It was an obvious "infomercial. 

Seemed to me Kiwi reactions were quite muted.

Of course one Brit rant and then your poisonous outburst.

Perhaps you could find another source of Cup news and commentary.

It would  lower your blood pressure and improve the climate here

[Forourselves 1,161]

42 minutes ago, Priscilla said:

Crikey as erudite as ever at least you’re consistent.

There you are again, just popping up as soon as I post something. I'm flattered lol. Are you a Kiwi today? or just another bandwagon jumper sitting on the fence? 

[RobG 753]

2 hours ago, Priscilla said:

Crikey as erudite as ever at least you’re consistent.

The ignore option is really quite good, except it's defeated by quotes. 

[Tommy22 24]

Does anyone have any idea what happened today? Short trip out 

[Indio 893]

4 hours ago, Offshore 1 said:

COVID affects us all in different ways. If you need a hug just reach out

Fuck that hug!! He can stay the fuck away from us

[barfy 1,122]

5 hours ago, JALhazmat said:

so getting tied up that the bulb has changed by 20% is a road to no where, as it’s the entire structure as a whole that you need to consider. 

And no one but the MC has any idea of the mass within the change regions of the iges file...

So Probly have to give up guessing on remaining foils and let the MC do their job.

[The_Alchemist 1,256]

7 hours ago, JALhazmat said:

It’s not about the bloody bulb!
 

anything that’s  in the box below the foil arm is subject to the 20% change by area, the change to area can only be accommodated within the 20% mass change. 
 

if making it 20% bigger (the foil assembly) is going to add more than 20% mass of the original then you can’t do it 

so getting tied up that the bulb has changed by 20% is a road to no where, as it’s the entire structure as a whole that you need to consider. 

My understanding comes from 5.10 (b) & (c)  

where it states that the 80% that remains must match the original components.  ...unmodified and in the same place in both versions.

That doesn't leave a lot of room for moving wings around at different angles and still call them in the original place.

The part that is fuzzy is in section (f) where they allow them to declare a hypothetical "original component" where it is not required to be identical to the component when it is first installed.  This looks like the basically throws out the constraints of the earlier parts of the rule.

 

5.10 For components listed in Rule 5.1 that have a “Change allowance” mass percentage:
(a) When such a component is first declared according to Rule 5.5, the Competitor must declare to the
Measurement Committee:
(i) a component mass;
(ii) an IGES file of an exterior component shape; and
(iii) construction drawings showing the internal structure of the component.
(b) At all times when that component is installed on an AC75 Class Yacht with that yacht afloat:
(i) at least 80% of the mass of the component must match the original component; and

(ii) a common portion of at least 80% of the mass of the original component must remain un-
modified and must match all declared versions of the component.

(c) The portion of mass of a component that matches another version of that component is determined
by aligning the unmodified portion of the original and modified components and determining the
mass of all regions where the material substance remains unmodified and in the same place in both
versions of the component.
(d) Material that has been replaced with identical or equivalent material only classifies as an unmodified
region where replacement was carried out as a repair permitted by Rule 5.12.

(e) When checking the shape of such a component against a declared IGES file, the Measurement Com-
mittee may make an allowance for unintended distortion of a component during manufacture.

(f) Competitors may declare a hypothetical “original component” which must comply with the relevant
rules for that component type, but is not required to be identical to the component when it is first
installed and afloat. In this case, the “original component” comprises those regions of the actual
component as-launched that match the hypothetical component, combined with the regions in the
hypothetical component that do not match the as-launched component and are presumed to have
been removed/modified to achieve the as-launched component. The component as first launched
must have corresponding declarations which must satisfy the permitted changes with respect to the
hypothetical “original component”.
(g) If the component when it is first installed and afloat does not comply with the relevant rules for that
component type, the Competitor must declare a hypothetical component that does comply with
those rules, in accordance with Rule 5.10 (f).

 

[JALhazmat 1,175]

I should have clarified that you can change an unlimited % ( not 20%of area) as long as the area change is the equivalent of the 20%mass  based on the submitted and approved IGES file 

[enigmatically2 758]

1 hour ago, The_Alchemist said:

 

The part that is fuzzy is in section (f) where they allow them to declare a hypothetical "original component" where it is not required to be identical to the component when it is first installed.  This looks like the basically throws out the constraints of the earlier parts of the rule.

 

That doesn't throw out the constraints. What it means is effectively they can chose the 80%. Take the following simplified example. 

My first foil is ABCDEFGHIJ

My second is 12CDEFGHIJ. That has only changed by 20% so all is well.

But then the third is

12CDEFGH98. That is more than 20% changed from the first one so that would at first sight seem illegal. However clause f allows them to say that the 80% bit is 12CDEFGH. then even though that is not what was in the first foil, all 3 foils only have 20% changed from that. so they are all legal compared to the "declared original"

Though I suspect the 20% of mass changed bit is open to a lot of interpretation in other ways, so I foresee some protests/clarifications

[The_Alchemist 1,256]

1 hour ago, enigmatically2 said:

That doesn't throw out the constraints. What it means is effectively they can chose the 80%. Take the following simplified example. 

My first foil is ABCDEFGHIJ

My second is 12CDEFGHIJ. That has only changed by 20% so all is well.

But then the third is

12CDEFGH98. That is more than 20% changed from the first one so that would at first sight seem illegal. However clause f allows them to say that the 80% bit is 12CDEFGH. then even though that is not what was in the first foil, all 3 foils only have 20% changed from that. so they are all legal compared to the "declared original"

Though I suspect the 20% of mass changed bit is open to a lot of interpretation in other ways, so I foresee some protests/clarifications

So are you saying the limit is a 20% change from the last change?  That basically throws out the limitations in what you can change, it just defines the steps you take to make the change (20% at a time).  It is confusing it what is actually allowed.

[The_Alchemist 1,256]

2 hours ago, JALhazmat said:

I should have clarified that you can change an unlimited % ( not 20%of area) as long as the area change is the equivalent of the 20%mass  based on the submitted and approved IGES file 

It is 20% of mass, but that means the other 80% of mass has to be identical to the original in position, shape, location, etc...   but you have (f) that seems to open it back up....with hypothetical original components.

[JALhazmat 1,175]

Ffs can you just read the bloody rules.. 

[phill_nz 645]

5.10
For components listed in Rule 5.1 that have a “Change allowance” mass percentage:
(a)
(b)
5.11
When such a component is first declared according to Rule 5.5, the Competitor must declare to the
Measurement Committee:
(i) a component mass;
(ii) an IGES file of an exterior component shape; and
(iii) construction drawings showing the internal structure of the component.
At all times when that component is installed on an AC75 Class Yacht with that yacht afloat:
(i) at least 80% of the mass of the component must match the original component; and
(ii) a common portion of at least 80% of the mass of the original component must remain un-
modified and must match all declared versions of the component.
(c) The portion of mass of a component that matches another version of that component is determined
by aligning the unmodified portion of the original and modified components and determining the
mass of all regions where the material substance remains unmodified and in the same place in both
versions of the component.
(d) Material that has been replaced with identical or equivalent material only classifies as an unmodified
region where replacement was carried out as a repair permitted by Rule 5.12.
(e) When checking the shape of such a component against a declared IGES file, the Measurement Com-
mittee may make an allowance for unintended distortion of a component during manufacture.
(f) Competitors may declare a hypothetical “original component” which must comply with the relevant
rules for that component type, but is not required to be identical to the component when it is first
installed and afloat. In this case, the “original component” comprises those regions of the actual
component as-launched that match the hypothetical component, combined with the regions in the
hypothetical component that do not match the as-launched component and are presumed to have
been removed/modified to achieve the as-launched component. The component as first launched
must have corresponding declarations which must satisfy the permitted changes with respect to the
hypothetical “original component”.
(g) If the component when it is first installed and afloat does not comply with the relevant rules for that
component type, the Competitor must declare a hypothetical component that does comply with
those rules, in accordance with Rule 5.10

 

you may only step 20% from the original

you may not step 20% then step another 20% from that

the same 80% of the part must remain unchanged for all changes to the part

[mako23 451]

10 hours ago, The_Alchemist said:

It is 20% of mass, but that means the other 80% of mass has to be identical to the original in position, shape, location, etc...   but you have (f) that seems to open it back up....with hypothetical original components.

They way I read this statement and I also did have a look at the rules, is that you could have a bulb made of lead and wings made of carbon fiber. As long as you don’t alter the bulb and the bulb equals 80 % of the mass you can change your wings as much as you like. Considering high light carbon is to lead you wouldn’t need a big bulb to be 80% of the weight. 

[NZL3481 383]

5 minutes ago, mako23 said:

They way I read this statement and I also did have a look at the rules, is that you could have a bulb made of lead and wings made of carbon fiber. As long as you don’t alter the bulb and the bulb equals 80 % of the mass you can change your wings as much as you like. Considering high light carbon is to lead you wouldn’t need a big bulb to be 80% of the weight. 

You're assuming that the foil wings are carbon. That may not necessarily be the case...

[The_Alchemist 1,256]

4 hours ago, phill_nz said:

.......

you may only step 20% from the original

you may not step 20% then step another 20% from that

the same 80% of the part must remain unchanged for all changes to the part

That is how I was interpreting the rule when I posted it above.  

What is your interpretation of the hypothetical "original component" in section (f)?  The "but is not required to be identical to the component when it is first
installed and afloat. In this case, the “original component” comprises those regions of the actual component as-launched that match the hypothetical component, combined with the regions in the hypothetical component that do not match the as-launched component and are presumed to have been removed/modified to achieve the as-launched component." almost seems to open up a loop hole and allow more changes.

[mako23 451]

39 minutes ago, NZL3481 said:

You're assuming that the foil wings are carbon. That may not necessarily be the case...

You are totally right on that point. It could be made up by all sorts of material. 
interesting point is these wings at high speed might be suffering cavitation. So they need to be resistant to this damaging effect. 

[Ncik 154]

Hypothetical component + density trickery = as many foils for testing as you desire.

The trick will actually be to design only good ones so testing time is maximised and $$$ are minimised.

[enigmatically2 758]

12 hours ago, The_Alchemist said:

So are you saying the limit is a 20% change from the last change?  That basically throws out the limitations in what you can change, it just defines the steps you take to make the change (20% at a time).  It is confusing it what is actually allowed.

No, it is 20% change from whatever is "claimed" as the original, not from the last foil. so in the example I gave

My first foil is ABCDEFGHIJ

My second is 12CDEFGHIJ. 

The third foil is  12CDEFGH98

But I have declared my "original" to be the 2nd one, so anything that is 20% from that is fine

So XYDEFGH98 would not then be OK , because although only 20% from the previous foil it is more than 20% from the declared original. Similarly ABCDFGH98 because although onlt changed 20% from the first foil, it is more than 20% away from the "declared original"

But 12CD56GHIJ is fine, because only 20% has changed from the "declared original"

[barfy 1,122]

3 hours ago, Ncik said:

Hypothetical component + density trickery = as many foils for testing as you desire.

The trick will actually be to design only good ones so testing time is maximised and $$$ are minimised.

Best foil design will be the winning trick. Easy.