Emirates Team New Zealand.

[shebeen]

Nice clean solution there. Should be a quick fix.

View attachment 555691

full video here


From a holistic view, the AC is pushing boundaries so failures are required to find where they are located. The success is measured on the response to setbacks.
We can assume that they are confident that this is going to work, because if it is 'rushed' in anyway the consequences further down the line are going to be very complicated. What is pretty cool is that all the sensors really give amazing data to analyse.

I guess this retrofit bow kit will be put in to the existing hulls and a similar one in the new builds at construction time. So probably not the ideal solution for new boats but one that keeps them all identical.

Overall, this response came out really quick - will have to give them 9/10 for it. They will surely be nervously waiting on the next high impact pitchpole however!

 

[Sailbydate]

Before Dec 10th?

Maybe you were on the money, Kiwing

 

[enigmatically2]

Nice clean solution there. Should be a quick fix.

Listen. He said they are still designing the solution. That is just one drawing, not the final article

 

[Sailbydate]

Listen. He said they are still designing the solution. That is just one drawing, not the final article

Steady on, Riddle. Fortunately, I can read.

AC40: IMPLEMENTING THE SOLUTION

Just days ago, Emirates Team New Zealand buried the bow of their AC40 while testing in waves on Auckland’s Hauraki Gulf, which resulted in damage to the forward sections of the hull and deck structure. While the on-water team was recovering the yacht and returning to dock, the team’s engineers...

emirates-team-new-zealand.americascup.com

 

[Forourselves]

Listen. He said they are still designing the solution. That is just one drawing, not the final article

Nope. it says "they have designed an upgrade package"

 

[ChairborneRanger]

Nope. it says "they have designed an upgrade package"

An upgrade package is a good way to not say we are still designing the final solution.

 

[enigmatically2]

Steady on, Riddle. Fortunately, I can read.

AC40: IMPLEMENTING THE SOLUTION

Just days ago, Emirates Team New Zealand buried the bow of their AC40 while testing in waves on Auckland’s Hauraki Gulf, which resulted in damage to the forward sections of the hull and deck structure. While the on-water team was recovering the yacht and returning to dock, the team’s engineers...

emirates-team-new-zealand.americascup.com

Fair enough, I listened to the video and he said they were designing, not had designed

 

[JALhazmat]

Yeah. ETNZ desperately need to get a proper designer join its team, to try and save its rapidly fading reputation. I wonder what, Juan K is doing these days? ;-)

Oh behave
The point is either they didn’t build it properly or they didn’t design it properly. It doesn’t look good on either one I’m not calling for wholesale design changes just that they get it right the first time round it’s not like it’s the first boat they’ve built is it

 

[JALhazmat]

Wait, so 1 breakage and its a "poorly designed boat"? Jees the F50 must be a really shit boat then. That things had multiple breakages!

They’ve had multiple crashes into each other. Yes and bits have come off, that’s a bit different from having a nose dive in the front falling off.

Who designed and built the f50s? I didn’t think I’d ever see you going into bat for the F50 it’s strange times indeed.😂

 

[Forourselves]

They’ve had multiple crashes into each other. Yes and bits have come off, that’s a bit different from having a nose dive in the front falling off.

Who designed and built the f50s? I didn’t think I’d ever see you going into bat for the F50 it’s strange times indeed.😂

Capsizes, broken wings, broken grinding pedestals, Foil issues.
I'm not "going in to bat" for the F50, I'm saying its inconsistent of you to say the AC40 is a poorly designed boat based on the fact that its had 1 breakage, while accepting multiple breakages on the F50 and thinking its such a cool boat.

 

[Forourselves]

Oh behave
The point is either they didn’t build it properly or they didn’t design it properly. It doesn’t look good on either one I’m not calling for wholesale design changes just that they get it right the first time round it’s not like it’s the first boat they’ve built is it

Sometimes shit happens that has never happened before. Thats just life. They've dealt with it, move on.

 

[barfy]

https://www.sail-world.com/news/217742/Americas-Cup-Foil-Arm-explodes-in-test-Video in this video the foil reaches 27.3 tonnes before breaking - a fully loaded AC75 is pushing 7.5 tonnes. We can bump that up to 8 tonnes to account for the side loading from the rig. Load factor on static load vs foil failure is ~3.4. This is not the safety factor!! This doesn't account for any dynamic loading, add between 1-2g of dynamic loading and suddenly you're looking at a safety around 2. Safety factor has to be applied to the expected design loading, it is not based on static load! In fact in the video they even say it broke at just over 2.1x the working load! Not sure where this 5x is coming from! For reference safety factors of 1.5-2 for planes and 5 if your a civil engineer making concrete bridges....

Yes, the article you cite says over 2x the working load. Other media mentions testing to simulate striking an underwater object, testing to simulate bear away at full cant. You are really arguing about the safety factor built into the design load, and comparing it to concrete bridges.
Until you come up with the expected loads on the bow of the ac40, and the factor above that that the designers felt was appropriate, it it's difficult to say other that "I would think a factor of 5", as I did. The halo is a safety over design of 15.
Btw, show us some ....

 

[Zonker]

The point is either they didn’t build it properly or they didn’t design it properly.

Design - but only sort of. It did something they didn't think about. That's VERY typical of many engineering failures. Things break because of load cases you didn't anticipate.

If you do your analysis properly on a bunch of load cases it is straightforward to design the structure to take these loads.

It's very easy to say "OK if the boat stuffs it's nose it will take XX seconds to slow down so that's YY g's and it's underwater 1.4m so that's an extra hydrostatic pressure to add". Then design a structure that withstands that.

It's much harder to say "OK the boat does a nosedive and at the same time rounds up and stuffs the bow sideways and the jib maybe fills with water too as it tries to come up". BECAUSE they didn't think about that particular load case.

"Oh we didn't think Bruce would drop the foil at just the wrong time to catch a tip on a whale and the whole boat does a reverse backflip and lands upside down...."

 

[Sailbydate]

If you do your analysis properly on a bunch of load cases it is straightforward to design the structure to take these loads.

"Oh we didn't think Bruce would drop the foil at just the wrong time to catch a tip on a whale and the whole boat does a reverse backflip and lands upside down...."

Love to see the structural modification design, for that scenario, Zonker. ;-)

 

[Zonker]

Simple - Boat Mk. II

 

[Ex Machina]

Who the feck is Bruce ?

 

[Jethrow]

Who the feck is Bruce ?

Obviously don't let him near the switches!

 

[enigmatically2]

Who the feck is Bruce ?

Philosophy department?

 

[Scillyjosh]

Yes, the article you cite says over 2x the working load. Other media mentions testing to simulate striking an underwater object, testing to simulate bear away at full cant. You are really arguing about the safety factor built into the design load, and comparing it to concrete bridges.
Until you come up with the expected loads on the bow of the ac40, and the factor above that that the designers felt was appropriate, it it's difficult to say other that "I would think a factor of 5", as I did. The halo is a safety over design of 15.
Btw, show us some ....

I really doubt any engineer thought a factor of 5 was appropriate. If you get to the end of your load case definition and analysis and think "yep lets multiple this by 5" then you've definitely not defined your load cases properly and should have no confidence in the engineering. This is a high performance structure solving a cutting edge engineering problem you have to produce quality load definitions and perform rigorous analysis. Not apply arbitrary multipliers to static loads.

The halo safety factor is wrong, yes it can withstand 15 times the weight of the car on it but in reality it's been designed to help 10-20g crashes into solid stuff, an entire car bouncing of it or driving into a crane. These events will be pretty high energy....

Judging by the videos and the acceleration plots they show I'll go out on a limb and say this crash was 20-30% more acceleration than they saw on the full scape boat impacts and took this structure just above it's design load. Looks like local buckling on the upper panel, maybe from core shear failure, caused global buckling of the structure. If the structure was massively under on strength the whole bow would have ripped off!

 

[The_Alchemist]

Design - but only sort of. It did something they didn't think about. That's VERY typical of many engineering failures. Things break because of load cases you didn't anticipate.

If you do your analysis properly on a bunch of load cases it is straightforward to design the structure to take these loads.

It's very easy to say "OK if the boat stuffs it's nose it will take XX seconds to slow down so that's YY g's and it's underwater 1.4m so that's an extra hydrostatic pressure to add". Then design a structure that withstands that.

It's much harder to say "OK the boat does a nosedive and at the same time rounds up and stuffs the bow sideways and the jib maybe fills with water too as it tries to come up". BECAUSE they didn't think about that particular load case.

"Oh we didn't think Bruce would drop the foil at just the wrong time to catch a tip on a whale and the whole boat does a reverse backflip and lands upside down...."

But the scenario you discussed is the only way it would nose dive. The nose dive is created by losing the rudder which causes the boat to dive and spin on the only point of contact with the water (foil). And if they assumed a 1.4 meter dive, then it would have to submerge the Jib. It is just a matter considering all of the variables not just some of them.