Vendee Globe and Alex Thomson / Hugo Boss

[flaming]

True, but his observations about stress concentrations were pertinent.

....With the assumption that no unseen stress mitigation was done. For example the cap thickness is not known, and nor is it known if it is even throughout, or greater at the areas of stress concentration.

The only real known fact here is that the structure failed. What isn't known is what caused it to fail, whether that load had even been considered in designing the structure, whether if it had been considered it had been accurately modelled etc... Or if this was a load that was so far out of the norm that it would not have been reasonable to have predicted.

The thing I took from the pictures of the structure was that they clearly had very particular expectations of where the loads would be, as I can't believe that those cutouts were just random. So my feel is that the structure had more to do with supporting the deck under the various furler attachment points by being in tension than any compression loading. It could even be that by putting that structure in to take the loads of the furlers they have made the whole bow too stiff and that the pounding that the boat takes falling off its foils just created shock loads that were too much, simply because the structure wasn't dissipating any energy. But again, I'm not basing that on anything remotely scientific and my basic 1st year engineering compulsory structures module from 15 years ago in no way compares to the experience and qualifications of the people who actually designed the thing.

 

[matt1]

A clearly devastated and emotional Alex has just put a video on FB. So sad and feels like his last Vendee. Let's hope I'm wrong.

Ok, he will be 50/51 for the next one, but for me he was demonstrating the best sailing he has ever done, has huge experience and I'd like to see him go round again. Fingers crossed that experience doesn't go to waste!

 

[Ravi]

The race looks to be fasinatingl poised.

Will Dalin"s far North route mean he has to slow down to cope with the Agula overalls? Will he have to cut South, losing speed reaching in big seas?

Does Burton's Southern route work? It is the optimal route for wind direction and distance but how will his boat perform in the bigger seas? His recent tactics have closed 50 miles on Dalin, who is sailing more conservatively. But is he tweaking the nose if the Southern Ocean by sailing South into the strong Northerlies of the slowing weather system?

And will the chasing boats close the gap while the leaders struggle with the band of mucky weather S of the Cape? Or will the leaders be catapulted further ahead?
And what will Le Can do next?
What a great race!

 

[flaming]

A clearly devastated and emotional Alex has just put a video on FB. So sad and feels like his last Vendee. Let's hope I'm wrong.

Ok, he will be 50/51 for the next one, but for me he was demonstrating the best sailing he has ever done, has huge experience and I'd like to see him go round again. Fingers crossed that experience doesn't go to waste!

I'm pretty sure he's on record as saying this was his last shot, but we'll see.

There are a couple of comments attributed to him about other races (Great Capes race for example) that seem to indicate he wasn't necessarily done with the IMOCA, even if it wasn't him on the boat for the next Vendee. But from what he's said before the family is becoming more pertinent in his decision to carry on racing.

Suspect we won't hear anything either way for a while yet. But if you hear he's getting divorced then stick some money on him winning the next Vendee....

 

[NormanB]

There were an awful lot of assumptions in that video that may, or may not, be accurate.

Of course there were and in fact the whole design that the team produced for real was based on just as many, if not more, assumptions. The old adage(s) is a that model illustrates a complex problem in a more simple construct to aid understanding and ‘all models are wrong’

I have not seen a better explanation of the HB bow structural failure anywhere on the net/YT.

 

[flaming]

The race looks to be fasinatingl poised.

Will Dalin"s far North route mean he has to slow down to cope with the Agula overalls? Will he have to cut South, losing speed reaching in big seas?

Does Burton's Southern route work? It is the optimal route for wind direction and distance but how will his boat perform in the bigger seas? His recent tactics have closed 50 miles on Dalin, who is sailing more conservatively. But is he tweaking the nose if the Southern Ocean by sailing South into the strong Northerlies of the slowing weather system?

And will the chasing boats close the gap while the leaders struggle with the band of mucky weather S of the Cape? Or will the leaders be catapulted further ahead?
And what will Le Can do next?
What a great race!

Good questions! I think I'd rather be in Dalin's shoes than those to the South. He has more options to manage the weather ahead. And he has a nice healthy lead to allow him to back off if necessary.

The most disappointing performance at the moment is Sam Davies. A couple of days back she was alongside BV2, but now she's 160 miles back and that seems to be just speed. Hope she can find another gear.

And JLC is just immense.

And meanwhile Pip and the rest of her gang are just getting into the Southern Ocean, and look like they should catch the next band of breeze. That will be fun to watch, especially as L'Occitaine is there. The following group look like they're going to get a real rough deal though.

 

[Seven Spades]

Le Cam is 60, Sir robin Knox-Johnson did the Velux-5-Oceans at 67 so never is a long time. I will be very disappointed if he does not try again. he had a fantastic boat this looked like his year.Last time he was valiantly second and Hugo Boss have had a great image. It would be a real shame to cancel this, getting another sponsor like Hugo Boss won't be easy and he must be the envy of the fleet to have such a supporter.

 

[Frogmogman]

A clearly devastated and emotional Alex has just put a video on FB. So sad and feels like his last Vendee. Let's hope I'm wrong.

Just watched this.

Heartbreaking.

 

[matt1]

A couple of people on here have commented that this would be his last Vendee, but I've never heard him say that and I follow him & the rave pretty avidly. I'd like to think I would have remembered that, but maybe not. It's not an unreasonable assumption though; age/family/ sponsorship etc. I doubt he will commit to anything immediately, but hopefully over the fullness of time we will get to hear what he is up to. Without doubt he's an impressive ambassador for our sport and it would be sad if it all ends here and in this way

 

[flaming]

A couple of people on here have commented that this would be his last Vendee, but I've never heard him say that and I follow him & the rave pretty avidly. I'd like to think I would have remembered that, but maybe not. It's not an unreasonable assumption though; age/family/ sponsorship etc. I doubt he will commit to anything immediately, but hopefully over the fullness of time we will get to hear what he is up to. Without doubt he's an impressive ambassador for our sport and it would be sad if it all ends here and in this way

He said after the last one that his wife had agreed to "one more shot".

I wouldn't rule him out for 2024 at all. But I also think he might be done and wanting a new challenge.

 

[matt1]

I'm hoping "one more" doesn't translate to "one last"... ;-)

The trouble with the Vendee is it's a bit binary and Alex was all out to win it, rather than just going round again (which others seem fine doing). You have to wonder what you go and do next after 20 years pf pursuing that ultimate goal. Whilst there are other IMOCA events, they don't seem to have the stature or interest. He's very good at setting records but I think it's the competition that drives him.

 

[Sandy]

Agreed. As his model didn't show any stress rise in one of the areas that fractured, I'd be high sceptical of the rest. He started off with, he is not a boat design/engineer etc, nor does he have the precise dimensions/radii or material composition. It look as like that there are extra carbon layers in some areas.

All that his modelling shows, is that it is extremely difficult to get a model to come close to what the actual loads and stresses might be!

Given the extremely limited amount of data he had it is the best we have until somebody gets their hands on the documentation.

Materials engineering is simple as materials usually behave in the same way no matter how we use them. Personally, of like to see the 3D, or should that be 4D with addition of time, modelling on the structure.

 

[john_morris_uk]

Shall I ask my daughter? On the completely random bit of trivia that her friend was the Hugo Boss team chef in the last few weeks leading up to the start. Perhaps she’ll get some inside gossip to feed all your speculation.

The truth might be that Alex has promised his wife this is the last one. Who knows.

I should have put the first para in the dubious connections thread that was running..!

 

[TLouth7]

I thought I might as well have a go at some FEA, seeing as how everyone is so interested. The important thing to note is that the area of the cracks is very much secondary structure. Compare the size of that little intermediate brace with the big diagonal that comes down from the top of the forward bulkhead.

In the below images left is forward, right is aft. I have constrained the right hand side (bulkhead), and applied tension forces at the top of the forward bulkhead and central post to mimic forestay loads. As you can see this results in no stress in the foreward bulkhead or forward floor. Load is carried in the main truss elements.


Now if we add a large upward force from slamming in the forward part of the floor you can see that the floor deforms, and this causes issues where the small intermediate strut joins the main members. Specifically the bottom end of the strut is trying to move up and left, causing bending moments to be applied at the ends.


This result is even more obvious if we ignore the forestay loads and only consider the upwards force on the floor:

It is not clear to me what the small intermediate braces are for: the forward diagonal is in tension so doesn't need support against buckling, and if you wanted to stiffen the floor member then this is not the obvious geometry; a strut that is closer to perpendicular to the floor would be better for that. NB I am not saying that the design is flawed, just that it is not clear to me what those members are for.

 

[pyrojames]

I'd be interested to see where the deceleration forces associated with pounding turn up...

 

[cherod]

A clearly devastated and emotional Alex has just put a video on FB. So sad and feels like his last Vendee. Let's hope I'm wrong.

Ok, he will be 50/51 for the next one, but for me he was demonstrating the best sailing he has ever done, has huge experience and I'd like to see him go round again. Fingers crossed that experience doesn't go to waste!

watched that ,, yes got to have dome sympathy with the guy

 

[TLouth7]

I'd be interested to see where the deceleration forces associated with pounding turn up...

In the end it makes no difference whether a stationary boat receives a sharp upwards force in the bow area from a big lump of moving water, or a forward pitching boat slams into stationary water. The difference is only in the reference frame applied.

Broadly there is an increase in backstay and mast compression load, a reduction in forestay load, and a great big bending moment in the hull. Locally there is upward force on the forward parts of the hull floor (and in a conventional hull inwards force on the sloping hull sides near the bow.

The bending moment ends up in the box formed by the hull floor and sides and the deck, plus any fore and aft structures like the one under discussion. The upwards forces on the floor should transfer into the ring beams and stringers etc.

Of course it is no doubt much more complex than that, but I would be surprised if we ever get to see a proper analysis of one of these boats.

 

[Frogmogman]

Of course it is no doubt much more complex than that, but I would be surprised if we ever get to see a proper analysis of one of these boats.

Indeed. VPLP may we’ll get to the bottom of it; whether they choose to share it with the rest of us is another thing entirely.

 

[E39mad]

PRB has activated his distress beacon due to "ingress of water"

Jean Le Cam is the nearest and is heading for him.

 

[Frogmogman]

PRB has activated his distress beacon due to "ingress of water"

Jean Le Cam is the nearest and is heading for him.

Crikey. Let's hope that he either manages to stem the flow, or Le Cam manages to take him off safely.

There is some symmetry in this, as it was a previous PRB (albeit with Vincent Riou at the helm), who rescued Jean Le Cam in January 2009 when the bulb fell off the keel of his boat VM Materiaux 200 miles West of Cape Horn.

At this rate of attrition, maybe JLC will find himself on top of the podium.....