80' trimaran for Route du Rhum to be skippered by Lionel Lemanchois

Discussion in 'Multihulls' started by Corley, Aug 24, 2012.

  1. Corley
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    Corley epoxy coated

    Cat 1 requires you to be able to seal the companionway with a hatch from the inside which I gather Lionel has done. With the volume in the beams and the boats relatively light weight I would not be surprised if the main hull is clear of the water.
     
  2. Blackburn
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    Blackburn Senior Member

    That's comforting Corley.

    Yesterday he had a couple of Frigate Tunas visit him, and who knows what other nasty beasts could be lurking below...

    PdB1.jpg


    ...
     
  3. cavalier mk2
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    cavalier mk2 Senior Member

    I think they'll have to do the bows down end over end righting technique to avoid the huge buoyancy complication of the beams. They have hull volume these days........
     
  4. Corley
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    Corley epoxy coated

    latest facebook update from the Prince de Bretagne page:

    https://www.facebook.com/MaxiPrinceDeBretagne

    rough bing translate:

    On Monday, Lionel Lemonchois embarks a "fishing operation" to his Maxi80 Prince de Bretagne returned.
    The goal: liven up meals - far consisting mostly of freeze-dried - fresh fish dishes. And because, after a couple of Wahoo yesterday, today dolphinfish that revolve around his boat and come up to him Tickle feet when he walks on his trampoline.
    The skipper therefore embarked on the manufacture of a cane (fishing rod) with the equipment on board. It has thus poking around in his Toolbox. Screws, end and bolts for lester all... now voila. It remains now for him to wait for it to bite.
    Meanwhile, the tug that comes its way, continues at 7 knots of average. At 12 o'clock, it was 590 miles its position
     
  5. Blackburn
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    Blackburn Senior Member

    ^^^

    Next time, he'll remember to bring along a pole and reel!

    Bing and Google both translate thazard as 'wahoo', but they're not the same kettle of fish.

    .....

    Cavalier raises an interesting question, where are they going to attach all that chain in order to bring the boat over? Perhaps on the bow to go end over end? Or along one of the amas, to go over sideways?

    If you depress the bows, then righting the boat will be more controlled and it won't come crashing down as much?

    Would you pump water into the boat after attaching chain, in order to sink it more? With the pumps and inflatable bladders mentioned on their shopping list, what are they thinking of doing?

    PDB.jpg
     
  6. cavalier mk2
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    cavalier mk2 Senior Member

    I'd flood the bows of all 3 hulls as far back as possible. Keeping the chain attached is a interesting question. The way these boats are going over it makes sense to start building them with the attach points and fill plugs needed to get them back on their feet.

    The problem with the side approach is the ama and half the beams would need to be flooded. Their engineers will no doubt have worked out the flotation of the various constructions used and will plan accordingly. For instance, what has foam core, how are the beams constructed etc.....
     
  7. Blackburn
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    Blackburn Senior Member

    Sounds sensible. On the other hand, would there be another way to do it, if for any reason they were averse to flooding the boat and sinking the bows?

    Here's a vague idea: you attach all the chain to one ama, submerging it more, then raise up the opposite side with air bladders. Next you have a bridle going from the tugboat across PDB to the bow and stern of the upturned ama on the high side. Would the tugboat then be able to right PDB?


    ....

    Today's item on the PDB website:

     
  8. Doug Lord
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    Doug Lord Flight Ready

    Thanks, Blackburn-pretty cool about the visit from the other sailor-bet that made Lionels day......
     
  9. cavalier mk2
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    cavalier mk2 Senior Member

    You'd need to flood the ama and that would leave the questions of flooding the beams, remember how they hold the whole boat up? The tug might be able to pull it over depending on the side slip but it will make a bigger splash. Seems harder and less gentle to me but the structure should handle it. One thing to remember is the enormous pressure exerted on a buoyant hull forced underwater. Flooding equalizes the pressure making an implosion much less possible. The beam fairings would be a question for me. With the flooded bows method the beams are set far enough aft to leave them alone, the forward beam should provide some nice lateral stability to the pull over.
     
  10. Blackburn
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    Blackburn Senior Member


    The implosion issue ... I remember once we were racing against some very good sailors who had a Firebird and were leading us, and when they jibed in heavy air just before the final stretch their bows went into a most magnificent nosedive which - although they popped up and stayed afloat - did indeed implode one or both hulls.

    I just made a call to a very good friend of mine, who I've had the great good luck to sail and own boats with, and asked him what he thought the Frenchies were thinking of doing with PDB.

    He thought they would right the boat sideways, that they'd very carefully make sure all the 6-8 compartments in the chosen ama were entirely flooded, and that they would use the airbags to stabilize that ama so that it remained level during the flooding process.

    The airbags he'd prefer to use are apparently available commercially, equipped with webbing straps and connecting tubes so that they can even out the buoyancy on both sides of a hull. Pumping equipment with the right accessories attached can adjust the amount of air in the bags, so that you can deflate and inflate them as desired during the salvage.

    The beams he's seen on Orma60's have featured drainage holes between compartments and inspection holes for draining (since there are so many fittings attached to them that they invariably leak), so he supposed that flooding and draining the PDB beams was probably not that difficult.

    What he outlined was basically to sink the one ama, and that the imposion forces were most critical to prevent since the ama might be as much as 10 meters under water. Then, after getting the boat to the 90 degree posture, the airbags could be gradually filled with air again. If the boat then came down a little hard it would not be anything it hadn't been designed to withstand.

    As regards sinking the bows instead, he said that sounded a lot more complicated. He thought there would be more risk of the boat not balancing evenly when tipped up, that it could sway to one side or another with resulting implosion forces on the more submerged part.

    ...

    Lionel was interviewed on French radio today, and said the tugboat was still 3-4 days from getting to him. I've not seen that interview online yet.


    ...

    In a post up the page I made the error of saying that it seems to be nearly 20 years since a big racing multihull has been righted and recovered at sea.

    Actually it seems to be almost 30 years ago!

    :cool:
     
  11. cavalier mk2
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    cavalier mk2 Senior Member

    Interesting info, the thing about the side rotation route is the whole ama structure has to go under to maximum depth. Bows down only the bows are at the deepest point, air bags can be attached at the ama hulls or the front beam at the rotation waterline to eliminate the corkscrew potential you mentioned. For my money it is less complicated and stressful as a simple tow over can then proceed, there will be no hard landing. It should be interesting to see what they do.
     
  12. Blackburn
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    Blackburn Senior Member

    They should try to do it first the one way, then capsize the boat all over again so as to test the other method as well!

    Then we'd know which system worked best.

    lol
     
  13. cavalier mk2
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    cavalier mk2 Senior Member

    The way these things often work there is a chance of that.....
     
  14. Blackburn
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    Blackburn Senior Member

    ^^^

    :D

    Very good!
     

  15. cavalier mk2
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    cavalier mk2 Senior Member

    Speaking of webbing straps, hooking the weight to the bow forestay attach point with webbing keeps the weight from sawing into the hull as it is rotated, once past 90 degrees the weight can be released/cut with a retrieval line left attached to the tug Is there a deposit on the chain?). I was wondering if they were worried about the strength of the hull extensions but the weight shouldn't have to exceed forestay loads and when inverted the big pull will be in the right direction for the attach points.

    The side roll weights would most likely be connected near the beam/ama joints but it would take more weight to sink, ama + beam cores....

    They had a helicopter overhead when they righted Credit Agricole but I suppose we won't be so lucky this time. Is it too late to send a kite camera?
     
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