Bolts in tension are never a wonderful design. Wonder if they had spring washers or locktight.

A statement from the team says the incident happened in light to moderate winds and 1-2m seas. The weather deteriorated after the incident. The girls are shaken and want a bit of time to get over it in private before facing the public spotlight.

Edit: Can't link statement but it's on FB, Nexba racing.

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Ramona said..

sydchris said..
More info about boat and crew here: rpayc.com.au/team-nexba-2022/

There was a FB post over the weekend confirming those on board and thanking the rescuers, but can't find it now.

Thanks for the link. I had read on an overseas forum of the accident and the crew but for some reason the Australian reports failed to mention the crew were two young women. The two women probably headed offshore into bad weather as part of a work up for the upcoming event. lets hope we hear of some kind of report into the incident for a change.

There has been plenty of work done including reports - iirc the below link has been placed on this forum before. Would assume that with the time and effort and cost which has gone into this specific yacht design and manufacture that the cause will be promptly determined and the design rectified as may be needed.

www.sailing.org/tools/documents/YRDTS2013Presentation-%5B17113%5D.pdf

Interesting that there is no suggestion of reducing keel material stress by increasing root area. The idea that a stainless or high tensile metal keel can be easily checked for deficiencies by a visual check is odd. Checking of welds is done in high stress areas by using radioactive sources and X raying of welds. We all know stainless can let go and it is one of the reasons wood and glass are so nice. Before they let go they show large cracks that even an idiot can see. This is also the case with good airplane design - a Jumbo can have cracks in it withouth falling apart. You can increase the critical crack length by using certain alloys and reducing the allowable material stress.
In Professional Boatbuilder magazine a decade or so ago, they did an article on testing of keels. The author went through a case where an Open 60 had hit the bottom with its keel. The keel then fell off. Suggestions were that x ray, or other analysis may have been able to see the sub surface damage. But an expert said that unless the keel was X rayed before installation then subsequent checking would not be useful for determining damage as you need a baseline.
Multis had this problem ages ago. Tris and cats used to fall apart quite a bit but have become more safe by reducing highly loaded metal connections.
The idea of having a fatigue limit (in the attached pwp) seems dumb to me. Fatigue problems only occur if you stress the material to a certain amount of its ultimate failure stress. For example DC 3 planes do not have a realistic fatigue limit. Other planes do, but the DC 3 was so overbuilt so that its mains spars don't ever get stressed to the point that the number of fatigue cycles will be reached in normal use. It is really easy to do this - just lower the allowable stress in any keel structure so that a dodgy weld or poor quality bolt will still be way above the stress that leads to fatigue failure. Although fatigue failure can't realistically be a problem with Newba as she is so new. For the rest of us, keeping away from high stress, low root keels is a good idea as the critical crack length may be smaller than visual inspection can detect.

PS - not an engineer, but I did engineer a couple of my cat designs. So I have a dangerous knowledge of boat loads and structures.

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lydia said..
T
In a keel box design there will often be bolts on the vertical holding it up (tension) and bolts on the horizontal (shear) across the keel box usually at the aft end.
Sorry should have explained better

Ok.
In the pic Shaggy posted I can't see any holes. But as you said if they are aft you won't be able to see them. Not a lot of surface area on-top of that for many bolts. Maybe a big pin that goes through the keel box and top of keel.
Again lucky they are both OK. Quite an eye opener for them.
Will be interesting to hear the outcome. Don't know exactly where it happened but any chance of salvaging the keel or is it too deep.

The keel is 15 miles East of Wollongong.

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Ramona said..
The keel is 15 miles East of Wollongong.

And probably hit the bottom doing 50 knots!

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julesmoto said..

Chris 249 said..

shaggybaxter said..
I am just chuffed to hear that everyone is safe. Sitting on a hull for anything even resembling 15 odd hours...man that'd be cold enough to seriously debilitate anyone, even in full kit. I feel for them, it must be just shattering after all that hard work making it a reality.
Jules, I don't know if I agree about wide beam = pinned upside down. I've never heard of one case where a boat stayed inverted due to a wide beam. And I specifically asked this exact question of a lot of yacht designers.
The X2 is a pure race boat that's all about getting every gram of weight out that they could whilst still qualifying for the S2H. The quoted specs of 2400kgs it less than half of the 12.50 with similar LOA/beam ratio.
I was comparing the difference in keel stubs a while back Nice example of the different design philosophies and weight reduction from a cruiser/racer to a thoroughbred racer albeit she is 10' shorter (the 12.50 keel is 50% deeper draft from the pivot bearing for a scale of reference).


Edit: Sorry Julesmoto, you mentioned issues with righting of not just beamy boats, but with keel issues. Didn't read it properly, apologies.

There's been quite a few instances where a yacht stayed upside down with keel attached for far too long.

1- In the 1996, Thierry Dubois' Open 60 remained inverted with keel on for at least 24 hours.

www.racecarmarine.com/News/95756/When-yachts-capsize-in-mountainous-seas-and-high-winds

2- The de Ridder designed Liberty 47 in the 1991 Japan-Guam race stayed upside down for 15 to 45 minutes dependiong on your source, and only re-righted after enough water had come in to create a free-surface effect. Only one crew survived.

The Japanese then tested a conservative quarter tonner in calm water. They tipped it upside down four times andon three occasions it re-righted within 4 minutes once, after 9 minutes once, after 11 minutes once, and then did not re-right after 70 minutes! They believe that the difference was caused by the different trim the boat took on as it leaked while inverted. Without those slow leaks the boat would have stayed upright - and that was a fairly standard sort of boat. Of course, in reality waves will start the re-righting motion but the Japanese is fascinating because it shows how even in the same situation the same boat can take vastly different time to re-right. When the variation is so high even when the conditions are exactly the same, it's hard to make hard and fast rules from individual capsizes.

3- The Kiwi 35 Wingnuts stayed inverted and intact in a race on the Great Lakes, causing deaths.

4- In the 98 Hobart Naiad was inverted long enough for a crewman to drown.

That's just a few off the top of my head.

Yes remaining upside down for any more than a few moments is a bit of a worry when one considers the watertight properties of average companionway set ups including mine. Opening and leaking of lazarette and cockpit lockers while inverted is also a source of concern.

Joubert designs with no horizontal sliding companionway hatch have appeal in this regard and a Currawong sold last year (Granny Smith?) had an interesting naval style wheel controlled hatch with multiple latch arms/dogs. Problem is if you read stories of being pooped/ washed overboard many don't realise things are bad enough to justify locking such a hatch when the rogue wave comes along. Hence the term "rogue" I guess :(.

Interestingly, though, water coming in will create a "free surface" effect that can help a boat re-right, and a lot of accounts indicate that they don't take on as much water in reality as it appears to a scared crew. There were a bunch of classic cases in the '79 Fastnet, where crews hopped off after boats had rolled and appeared to be full of water, but were later recovered.

Just a slight thread drift here. This is a book well worth reading.

I hope they manage to sort out whatever the issue is. The Aussies involved appear to have put a huge amount of planning and detail into the design whilst trying to keep an eye on costs. Mind you, +$200k is still a lot of money in anyones language for a 30'er, but for a short handed race boat you are getting a lot of bang for your buck. I'd be tempted at looking at one if:
- the ultra light weight doesn't translate to a boat that exhausts the crew, especially as it's intended for short handing: and
- they can prove they can fix the keel issue. It's a big black mark they now have to surmount. My highest priority in an offshore yacht is structural integrity and images of a turtled boat doesn't quite fill one with confidence! A short thin chord with a bulb on the end already has physics working against you.
i think I'll remain an interested observer atm, but I wish them every success in their goal in making it a reality.

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Chris 249 said..

julesmoto said..

Chris 249 said..

shaggybaxter said..
I am just chuffed to hear that everyone is safe. Sitting on a hull for anything even resembling 15 odd hours...man that'd be cold enough to seriously debilitate anyone, even in full kit. I feel for them, it must be just shattering after all that hard work making it a reality.
Jules, I don't know if I agree about wide beam = pinned upside down. I've never heard of one case where a boat stayed inverted due to a wide beam. And I specifically asked this exact question of a lot of yacht designers.
The X2 is a pure race boat that's all about getting every gram of weight out that they could whilst still qualifying for the S2H. The quoted specs of 2400kgs it less than half of the 12.50 with similar LOA/beam ratio.
I was comparing the difference in keel stubs a while back Nice example of the different design philosophies and weight reduction from a cruiser/racer to a thoroughbred racer albeit she is 10' shorter (the 12.50 keel is 50% deeper draft from the pivot bearing for a scale of reference).


Edit: Sorry Julesmoto, you mentioned issues with righting of not just beamy boats, but with keel issues. Didn't read it properly, apologies.

There's been quite a few instances where a yacht stayed upside down with keel attached for far too long.

1- In the 1996, Thierry Dubois' Open 60 remained inverted with keel on for at least 24 hours.

www.racecarmarine.com/News/95756/When-yachts-capsize-in-mountainous-seas-and-high-winds

2- The de Ridder designed Liberty 47 in the 1991 Japan-Guam race stayed upside down for 15 to 45 minutes dependiong on your source, and only re-righted after enough water had come in to create a free-surface effect. Only one crew survived.

The Japanese then tested a conservative quarter tonner in calm water. They tipped it upside down four times andon three occasions it re-righted within 4 minutes once, after 9 minutes once, after 11 minutes once, and then did not re-right after 70 minutes! They believe that the difference was caused by the different trim the boat took on as it leaked while inverted. Without those slow leaks the boat would have stayed upright - and that was a fairly standard sort of boat. Of course, in reality waves will start the re-righting motion but the Japanese is fascinating because it shows how even in the same situation the same boat can take vastly different time to re-right. When the variation is so high even when the conditions are exactly the same, it's hard to make hard and fast rules from individual capsizes.

3- The Kiwi 35 Wingnuts stayed inverted and intact in a race on the Great Lakes, causing deaths.

4- In the 98 Hobart Naiad was inverted long enough for a crewman to drown.

That's just a few off the top of my head.

Yes remaining upside down for any more than a few moments is a bit of a worry when one considers the watertight properties of average companionway set ups including mine. Opening and leaking of lazarette and cockpit lockers while inverted is also a source of concern.

Joubert designs with no horizontal sliding companionway hatch have appeal in this regard and a Currawong sold last year (Granny Smith?) had an interesting naval style wheel controlled hatch with multiple latch arms/dogs. Problem is if you read stories of being pooped/ washed overboard many don't realise things are bad enough to justify locking such a hatch when the rogue wave comes along. Hence the term "rogue" I guess :(.

Interestingly, though, water coming in will create a "free surface" effect that can help a boat re-right, and a lot of accounts indicate that they don't take on as much water in reality as it appears to a scared crew. There were a bunch of classic cases in the '79 Fastnet, where crews hopped off after boats had rolled and appeared to be full of water, but were later recovered.

From this picture Id say there is a fair bit of water in the boat as it is floating pretty low. Obviously the rudders are gone as well as the keel and rig which is not surprising as they are of even lighter construction. Maybe someone gave a thought to inversion when they chose the rudders and keel paint.

That's incredible to lose both rudders, the keel and the rig all at once!. Hard to come back from there.

Sailing anarchy has some discussion. There is confusion as to the keel material. The Farr web site talks about milled steel, somewhere else says cast iron. If cast iron I would not be surprised at failure, given the small fixing "tab" and the clear stress concentration at the junction of keel and fixing tab.

Cast Iron is not very good for bending loads and tensile forces, particularly if there is a local stress raiser. It is also not wonderful for threaded bolts in tension.
Then there is the shock loads from this kind of racing hull slamming on waves...

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Keel and rudders must be painted a highly visible colour for RORC regulations. No good if there not there!
Again speculation but worrying the keel and both rudders are gone.
Scarry pic and well done again to both of them for surviving through that.
You can see why they made the high vis hoods mandatory as well. Imagine those 2 in the water. You wouldn't see the one without the high vis hood.
Let's hope they have good support and work their way through this. That could be the end of a career or motivation to make sure it doesn't happen again. Different people will react differently to a situation like that. One thing is for sure that will be in the back of their mind any time they go sailing. And it's the mental game that makes the difference.
Some advice I have been given in the past
To win, first you must finish. Winning comes later.
Always stay with the boat. They either sink straight away, I think under 1 minute we were told or they don't.

The more pics the more questions there are from a safety point if view.

So much for the hull deck join! Must use the same adhesive they use on Lagoon bulkheads.
At least the girls were dinghy sailors and therefore used to overturned hulls although not hulls without any capability of righting.Terrifying experience for them. Wonder where they go from here?

Where they go from here can only be decided by them individually. They need to be allowed to make those decisions themselves. They need good support and time to make the right decisions for each of them.
They are both very lucky to be alive.
You can argue weather it is right or wrong but when the regulations say the keel and rudders must be painted in high vis so they can be easily seen when the vessel is upturned you need to understand this can be part of offshore racing.

I cannot see that this design is suitable as an offshore capable yacht.

The manufacturer's view that they will implement improvements after the incident is rubbish. They should have done the testing before it was sold retail. If the boat and crew had been lost they would still sell the boat to an unsuspecting public.

I hate bureaucracy but it looks like we need more regulation of yacht building standards and testing.

I'll duck back below the parapet.

MB are you suggesting that they may have been unwitting test pilots ? Racing does push technological barriers, should the public be the guinea pig ? Red keel & rudder but no epirb ? Perhaps they were unlucky enough to hit a semi submerged container or a whale. Pure speculation

As I understand it, the whole idea of a male/female socket is the snug fit. It has to be nice and snug to transfer the loads into the supporting structure. The bolts 'just' hold it in this position. The X2 is designed to be shipped easily so the keel is removable, so I get the idea of why they went that way.
In the salvage photos the keel bolts are missing. The subframe the socket is encased in looked intact. If the keel stub snapped off the bolts would still be there, so I cant help but wonder if the bolts failed.
This looks like the X2 keel socket.


This is a Class 40 socket.......


This is the 12.50, so same hull but moulded for the swing keel..

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woko said..
MB are you suggesting that they may have been unwitting test pilots ? Racing does push technological barriers, should the public be the guinea pig ? Red keel & rudder but no epirb ? Perhaps they were unlucky enough to hit a semi submerged container or a whale. Pure speculation

An investigation must explore this possibility. If manufacturer negligence is found it could have a major impact on designer/builder accountability.

Interesting how the Nexba Racing statement identifies a "light to moderate breeze and 1-2metre seas" and Farr statement describes it as a "building breeze and significant seaway". I'd hate to think that 15knots wind and 1-2metre seas could be regarded as a challenge to any yacht's structural integrity. it's also a pity that those photographing the beached hull didn't include a pic of the keel fitting - with or without keel stub remaining. And, I understand that rapid keel loss and capsize can occur before an Epirb could be removed and triggered (especially at 0100hrs), but who spends $300k setting up a racing team then sends em out without PLB's?

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Bushdog said..
Interesting how the Nexba Racing statement identifies a "light to moderate breeze and 1-2metre seas" and Farr statement describes it as a "building breeze and significant seaway". I'd hate to think that 15knots wind and 1-2metre seas could be regarded as a challenge to any yacht's structural integrity. it's also a pity that those photographing the beached hull didn't include a pic of the keel fitting - with or without keel stub remaining. And, I understand that rapid keel loss and capsize can occur before an Epirb could be removed and triggered (especially at 0100hrs), but who spends $300k setting up a racing team then sends em out without PLB's?

Yes the weather was unpleasant long before the accident. I'm not sure where this bull **** about light breezes building is coming from. I was a few miles South of there Wednesday with very pleasant conditions. I went sailing that day because it was the pick of the weather. The following days were forecast for fresh winds and rising seas!

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Chris 249 said..
Just penalise keels with very short root chords compared to their draft and C of G and the loadings change dramatically and the structural problems become vastly easier to solve. Sure, the boats will be slower - by what, one minute per race? Is that really worth all the hassle and, even worse, the deaths caused by these keels?

Seems like a reasonable proposal

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woko said..
MB are you suggesting that they may have been unwitting test pilots ? Racing does push technological barriers, should the public be the guinea pig ? Red keel & rudder but no epirb ? Perhaps they were unlucky enough to hit a semi submerged container or a whale. Pure speculation

It's not that hard to create rules that ensure that critical technological barriers aren't being pushed. To look at something that's currently getting huge spectator interest, the Tour de France bikes have a minimum weight that means that the frames don't fall apart unless there's actually a serious collision, and even then they normally come up OK.

It's funny, in my former profession we had a huge number of rules and ethical principles to follow but none of our errors would kill people. It's getting to the stage where it's becoming reasonable to blame yacht designers for the deaths that are occurring with the losses of keels like this. It's a known problem, and merely saying that the customer wants them doesn't always cut it if you are going to call yourself a professional.

I would almost never say this, but I'd almost be happy to see a lawsuit and a big settlement against designers and builders for building this sort of keel. Killing people is not something to risk for something as banal as winning a boat race.

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Bushdog said..
Interesting how the Nexba Racing statement identifies a "light to moderate breeze and 1-2metre seas" and Farr statement describes it as a "building breeze and significant seaway". I'd hate to think that 15knots wind and 1-2metre seas could be regarded as a challenge to any yacht's structural integrity. it's also a pity that those photographing the beached hull didn't include a pic of the keel fitting - with or without keel stub remaining. And, I understand that rapid keel loss and capsize can occur before an Epirb could be removed and triggered (especially at 0100hrs), but who spends $300k setting up a racing team then sends em out without PLB's?

Allegedly they both had PLBs.The crew down below didn't get time to get theirs. The other one was smashed after the capsize.

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shaggybaxter said..
I hope they manage to sort out whatever the issue is. The Aussies involved appear to have put a huge amount of planning and detail into the design whilst trying to keep an eye on costs. Mind you, +$200k is still a lot of money in anyones language for a 30'er, but for a short handed race boat you are getting a lot of bang for your buck. I'd be tempted at looking at one if:
- the ultra light weight doesn't translate to a boat that exhausts the crew, especially as it's intended for short handing: and
- they can prove they can fix the keel issue. It's a big black mark they now have to surmount. My highest priority in an offshore yacht is structural integrity and images of a turtled boat doesn't quite fill one with confidence! A short thin chord with a bulb on the end already has physics working against you.
i think I'll remain an interested observer atm, but I wish them every success in their goal in making it a reality.

It does strike me as being a bit odd that over the past few years shorthanded IRC/ORC racing has become huge with people sailing boats like 10.5-11m Js, JPKs and Sunfasts, and now that the trend is well established a bunch of people are trying to hop aboard it with ultralight 30s. If we're finally seeing a sector of racing with strong growth wouldn't it be a good thing to foster and encourage the formula that has already proven successful (ie slightly bigger but less extreme boats) instead of trying to jumping someone ele's train with ultralights that fall apart?

It may be an example of the sort of thinking that is stuffing up the sport. Instead of seeing the strong points in the current trend that have made it a success, there's a move in the industry to sort of say "sod that, the recipe has been working but now we'll bring in a stripped out lightweight to f*ck over the popular boats and rain on their parade".

FFS, why not try to grow the sport by joining in with a successful theme rather than attacking it? Sure, the X2 was going to be a quick 30 footer but I bet the much cheaper 30 footer I did my last shorthanded offshore season on would beat it most of the time because that boat was a tri. Monos don't go as fast no matter what you do so wtf do people kill sailors (or risk doing so) to try to say 1/10th of a knot?

It's a mono, make it tough and simple 'cause it will never be really fast. May as well try to grow a bigger bonsai tree....