In the statement on the X2 published by planet sail above "at 16.40" it's explained that the tenon/socket system relies on surface area contact for its strength, not the bolts. The above pic of the of the keel socket "immediatley after beaching" looks like the contact between surfaces would have been minimal.

The keel box would not perfectly fit the keel strut so maybe remains of filler applied to get a good fit with rest on the keel strut maybe

If its is not a perfect fit it would be logical that strength is then compromised, based on what the manufacturer said about tenon/socket design.

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lydia said..

lydia said..
Looking into my crystal ball, the boat structure did not fail, the fin (cast iron) did not break.
See how I go.

And Yarra, it had a keel box as you describe btw.

Keel box immediately after beaching.

So how did you come across that picture?

He bubbly mess looks like water foam to me.
Have been wrong before though.
Bloody cold here in Japan this year

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lydia said..
The keel box would not perfectly fit the keel strut so maybe remains of filler applied to get a good fit with rest on the keel strut maybe

You'd imagine it would make an 'orrible racket if it was moving and be annoying if there was water sloshing around so you might be right that it is some kind of filler for when you insert the keel? Non structural expanding foam kinda thing?
Occams razor given the keel box appears intact is the nuts came undone?

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sparau said..

lydia said..
The keel box would not perfectly fit the keel strut so maybe remains of filler applied to get a good fit with rest on the keel strut maybe

You'd imagine it would make an 'orrible racket if it was moving and be annoying if there was water sloshing around so you might be right that it is some kind of filler for when you insert the keel? Non structural expanding foam kinda thing?
Occams razor given the keel box appears intact is the nuts came undone?

That was my thought too..the nuts came off.

Although l did have a wheel break all 5 studs without damaging the wheel itself once so anything is possible.

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Madmouse said..

sparau said..

lydia said..
The keel box would not perfectly fit the keel strut so maybe remains of filler applied to get a good fit with rest on the keel strut maybe

You'd imagine it would make an 'orrible racket if it was moving and be annoying if there was water sloshing around so you might be right that it is some kind of filler for when you insert the keel? Non structural expanding foam kinda thing?
Occams razor given the keel box appears intact is the nuts came undone?

That was my thought too..the nuts came off.

Although l did have a wheel break all 5 studs without damaging the wheel itself once so anything is possible.

I can't see how two nuts could both spontaneously come undone together, however assuming they did surely it would be incrementally in which case the keel would become progressively loose and make the 'orrible racket described above. My thoughts, after seeing that picture, are the surface contact in the tenon/socket joint was insufficient and caused the bolts to snap when they suddenly took the full load/leverage of the keel.

It looked like one bolt either stripped the thread in the keel or came undone. Then the other one pulled through the hull material. Backing plate/washer too small?

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Madmouse said..

sparau said..

lydia said..
The keel box would not perfectly fit the keel strut so maybe remains of filler applied to get a good fit with rest on the keel strut maybe

You'd imagine it would make an 'orrible racket if it was moving and be annoying if there was water sloshing around so you might be right that it is some kind of filler for when you insert the keel? Non structural expanding foam kinda thing?
Occams razor given the keel box appears intact is the nuts came undone?

That was my thought too..the nuts came off.

Although l did have a wheel break all 5 studs without damaging the wheel itself once so anything is possible.

The original fixings weren't nuts (much better idea) but bolts that tapped into the keel.

Oh dear, that has just opened my eyes to the construction/ connecting method. The designers are far smarter men than me but FFS

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Yara said..
It looked like one bolt either stripped the thread in the keel or came undone. Then the other one pulled through the hull material. Backing plate/washer too small?

That is certainly my take and that is why the manufacturer in the video says that they are not relying on threads of different materials mating.
The revised bolts are secured in the keel head at their lower extremities by a similar mechanism as is used in IKEA furniture (metal to metal thread) and of course the washers at the top are replaced by a much bigger area single washer (as compared with those in Shaggybaxters picture above) through which both bolts now pass.

An admission of guilt and poor design in the original product if ever I saw one.

Actually I often wonder why washers on most keel boats (including mine) are not much larger (although of course my boat has 12 not 2).

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garymalmgren said..
He bubbly mess looks like water foam to me.
Have been wrong before though.
Bloody cold here in Japan this year

Yeah I wondered if it could be that, I guess the low res / low light nature of the pic could make it look more solid.

rpayc.com.au/wp-content/uploads/2023/08/Nexba-Incident-Report-23-Jul-2023.pdf

Gday R13

Thanks a heap for that - very sobering to read how the crew were unable to get a good EPIRB/PLB signal out even with three on the boat and wearing bum bags. Very much food for thought - interesting also to note that the keel fell off in light winds and that the skipper tried three times to go back into the cabin to retrieve the EPIRB - that would be very scary. Hmmmm.

It sounds a bit as if they are leaning towards requiring everyone to carry mini air tanks, which is annoying when the actual root problem is that boats are losing high aspect bulb keels and inverting. Like the inspection requirements, it's pussyfooting around the real issue which has caused numerous deaths and will continue to cause deaths until the rulemakers do the simple thing and rate high aspect keels more heavily. Masts used to fall like twigs until they put a minor penalty on rigs that needed runners to stay up; now they stay up. This isnt rocket science.

It's odd that they can bring in rules that change safety requirements according to boat size and design but not also allow for the fact that boats with low aspect keels do NOT lose them and therefore don't need the same sort of rules as boats with keels that drop off regularly. If they bring in mini air tanks then even boats with full keels and encapsulated ballast will have to buy them at considerable expense, and the mini tanks are certainly not foolproof to use.

It's also interesting that they note that if the skipper had been using a water-activated PFD they may not have made it out of the cabin. The brave tries to get the PFD were scuttled partly by the wearing of seaboots. I think it's Ed Psaltis who said that in boats of 11m or less he just wears wetsuit boots because seaboots still get your feet wet and are clumsy. They could also be lethal if they got tangled while swimming.

They do make very good points about keeping beacons etc separate from each other. Perhaps one set of gear should be in another grab back secured to the stern rail?

So they had a warning of keel problems at the start, with a diver reporting keel "wear ", and an out of water inspection. Then the difficulty trying to tack. If they had more experience with the boat, they might have picked up that something was seriously wrong. With a new boat, some shakedown heavy weather daylight sailing inside Pittwater before doing a night offshore passage would have been a good idea.

Absolutely terrifying account. So glad no one died.

The search helicopter missed them and so did a ship first time around. When you think about it blue or white are not the smartest colours for antifouling or hull bottoms. Not too worried about my Northshore ever turing or sitting upside down but it might make sense to paint wide fluoro orange bands or zebra stripes on the bottom of my trailer sailer.

After all storm sails are supposed to be fluro orange now and the recent GGR boats were required to have fluoro dodgers. This type of regulation would not be too intrusive. It's not like you are going to be able to rig a V sheet in most of these sorts of situations

Well that was a waste of a read.
That is why these reports should not be undertaken.

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julesmoto said..
The search helicopter missed them and so did a ship first time around. When you think about it blue or white are not the smartest colours for antifouling or hull bottoms. Not too worried about my Northshore ever turing or sitting upside down but it might make sense to paint wide fluoro orange bands or zebra stripes on the bottom of my trailer sailer.

After all storm sails are supposed to be fluro orange now and the recent GGR boats were required to have fluoro dodgers. This type of regulation would not be too intrusive. It's not like you are going to be able to rig a V sheet in most of these sorts of situations

In any sort of sea it is extremely difficult to see things in the ocean. In bad seas almost impossible. Many years ago we were flying off HMAS MELBOURNE and couldn't actually see the ship until nearly on top. Grey ship and a grey ocean covered with whitecaps. A small white yacht doesn't stand a chance of being seen from the air without help.
A flash of orange colour stands out in all sea states.
But for me a 'signal mirror' or heliograph is the best signalling device during the day. Just point it in the direction of the aircraft and it will flash to attract attention.
At night a flashing strobe is best.

When Finistere lost it's keel a few years back, we didn't see the hull until it was literally 30 meters away (black antifloul). Heck the only reason we knew they were they were the strobe lights on the life jackets.

I casually crewed on Finistere in 2016 while working in WA. Such a loss, it still saddens me.

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EastCoastSail said..
I casually crewed on Finistere in 2016 while working in WA. Such a loss, it still saddens me.

Scary as hell. Got me wondering what lies inside my TS drop keel. Many keel losses are so instantaneous with no time to react.

I am having a hard time working out if the problems tacking were related to the keel falling off. Any ideas?

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Yara said..
With a new boat, some shakedown heavy weather daylight sailing inside Pittwater before doing a night offshore passage would have been a good idea.

They did daylight offshore sailing including 30 knots and lumpy seas, which is a fair bit more testing than sailing inside Pittwater.

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Kankama said..
I am having a hard time working out if the problems tacking were related to the keel falling off. Any ideas?

Just imagine the shallow hull, with very little to grab the water forward to act as a pivot point. All the rudders would do is cause drag and slide the boat sideways, but not enough force at the bow to push the bow through the wind.

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Chris 249 said..

Yara said..
With a new boat, some shakedown heavy weather daylight sailing inside Pittwater before doing a night offshore passage would have been a good idea.

They did daylight offshore sailing including 30 knots and lumpy seas, which is a fair bit more testing than sailing inside Pittwater.

It looks like that was insufficient time for the skipper to get a feel for the boat handling, in order to realise that something was wrong with the boat when it could not tack through the wind.

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Yara said..

Chris 249 said..

Yara said..
With a new boat, some shakedown heavy weather daylight sailing inside Pittwater before doing a night offshore passage would have been a good idea.

They did daylight offshore sailing including 30 knots and lumpy seas, which is a fair bit more testing than sailing inside Pittwater.

It looks like that was insufficient time for the skipper to get a feel for the boat handling, in order to realise that something was wrong with the boat when it could not tack through the wind.

If so, then more daylight sailing inside Pittwater (they already did a lot of it) may not have solved the issue. And we don't know whether the keel had fallen off when they had tacking issues. It all seems a bit odd - if the keel had fallen off around that time then the CLR would normally have moved dramatically aft and yet they had issues with the boat broaching, which generally indicates that the CLR is too far ahead of the CLE. The boat also "felt normal" after the problem with tacking.

Given the conditions, the very shallow rudders, the reef and the mast-aft rig it could well be that the keel was still in place but that the boat was hard to tack anyway. I admit, though, I'm not a fan of the boat because the fantastic boom in 2 handed racing is taking place in slower, simpler boats and arguably boats like the X2 could be against the proven formula that is creating one of racing's few success stories. When a shrinking sport finally finds a good formula it shouldn't mess with it IMHO.

Anyone else pick up the bit about the diver.
How does the diver see wear marks without wear from vertical movement?