Anchor stowing system with lateral movement

Discussion in 'Sailboats' started by winchgorilla, Apr 10, 2006.

  1. winchgorilla
    Joined: Feb 2004
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    winchgorilla Junior Member

    Hello to everybody!
    I have an urgent problem and don't know how to solve it. I need somekind of a name or firm or producer or anything what would help me with solving a problem with anchor stowing system with lateral movement. something like on IMX70 or what the Marten yachts have.
    Thank you for anykind of information.
    Matjaz
     
  2. DanishBagger
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    DanishBagger Never Again

    I don't have a name to give to you, but if you put your problem in writing (with a little more detail and such), I'm pretty sure the good people here can help you. either directly, or point you in the right direction.
     
  3. winchgorilla
    Joined: Feb 2004
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    winchgorilla Junior Member

    Anchor problem

    Thanks for reply to message.

    Well, the problem is like this. We are constructing and building a 52' sailing yacht, something very close to transpac 52' with lifting keel and lot of carbon.
    The problem is that we can't find nowhere on the Net somebody who is producing and manufacturing a self stowing anchor system except Cariboni.

    We were thinking on a solution that is incorporated for example on IMX70 or Marten 67. Somekind of a rotating ram mechanismus,(pictures).It doesn't need to have any hydraulics, can be rotated also manualy by hand.
    If you are interested to help, we would welcome it very much.

    If you know anybody that has already develop this kind of a system it would help us a lot, because in this preliminiray stage we need some main dimensions and maybe a mass of this solution so that we can proceed with our work.
    If you need more infos please tell us.
    With regards,
    Matjaz

    (http://www.aagnautika.com/aag-meni.htm)
     

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  4. DanishBagger
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    DanishBagger Never Again

    You're welcome, but just to make something clear, I am _not_ a naval architect or similar, so I'm pretty limited, personally, as to how much I can help. I want to, but that is obviously not enough. Abyways, just wanted to point out (the lack of) weight I carry ...

    Anyway, ofr what it is worth, isn't it basically a matter of figuring out the dimensions on that selfstowing system? Purchasing the rams and so forth (if hydraulic/pneumatic), hinges and so forth. I doubt that anyone is produucing "a system", I think you have to figure out what size anchor, what type, what type of rod, size, and then "simply", make a folding mechanism.

    Seriously, I believe it to be easier to be easier to design it for and to the boat than it owul dbe to define for someone making "systems".

    You seem to be able to "gleen" from the designs of others, and if I were you, I'd go that route. Make the calculations, make the sketches, and go from there-

    Now, with that said, I hope a naval architecht will jump in and prove me all wrong. :)
     
  5. french44
    Joined: Mar 2006
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    french44 Junior Member

    hi winchgorilla
    you need a rotaring bow sheave ,contact "accastillage bernards " a french company specialized in naval outfitting for sail boat and motor boat i don't know the web site but if you don't find i can send you the commercial book,
    otherwise give me more detail i use microstation v8 cad software and i can read dxf ,igs,dwg file format and give me your specification ,i made on yachts some "moring deck " and i can help you "it's free only for the fun" i can draw some principle give me your mail for the commercial book of french distributor and drawing if you want
     
  6. Karsten
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    Karsten Senior Member

    These things are like a big can of worms. First you have to figure out your load cases. Ideally you want to make the structure stronger than the anchor chain. Therefore the chain break load plus a safety factur gives you the ultimate load on the arm. This is usually quite massive and sometimes this load is reduced so that you don't have to mill the whole thing out of a solid piece of metal. Then you have to think about the direction of the anchor chain. It's going to point towards the bottom of the sea hopefully and you also have to take a certain side load into account. If you just rely on the hinge of the arm to transfer the side loads you will again end up with a support structure milled from solid metal. Therefore most arms have a locking pin where the arm contacts the topsides. This area also needs propper engineering because of the loads involved. Not good if the arm crushes the topsides. Now you also have a forestay up there maybe a jib furler and if you are unlucky a code 0 sheave and if the owner is gone mad he also might want a bowsprit. You can easily spent as much time engineering this are than you spent on the rest of the boat. If I was you I would just hand over the money to Cariboni and let them deal with it.

    Good luck,
    Karsten
     
  7. FAST FRED
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    FAST FRED Senior Member

    Why would you WANT the anchors and weight up on deck?

    The usual solution is to simply pull the anchor stock into a hawse hole in the hull side.

    No extra gear , no weight , and for "racing" a Fortress aluminum anchor would reduce the weight .

    Just look at most larger powerboats from the past.

    Another advantage is muck ect is NOT brought aboard , and daddy Neptune washes any mud off with no effort.

    P&S holes for a pair of anchors are common.


    Automatic , clean self stowing ,,Works for me!

    FAST FRED
     
  8. Sander Rave
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    Sander Rave Senior Member

    Hi Gorilla,

    seems like a neat device, but it won't help you reduce weight. Is this for a one off? If it's going to be a super yacht, it can be worth the expenses of developing the system. If not, you need a potential series de cover development costs.

    Have you seen real life pictures of the system, or is it only in the designers mind(s)?

    I'm an industrial designer/engineer and I like this case, looks like my piece of cake. Let me know when you need some advice in development.
     
  9. winchgorilla
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    winchgorilla Junior Member

    anchorage

    Thank you guys on yours advices.
    This will be a expensive sailboat that evoluate from transpac 52', it will be made from carbon/Nomex, rig is from Hallspar. We are trying to get the best from each area, but there are lot of small problems that we have to solve.
    One of these is this anchoring system. In our opinion we can go only on this version of anchoring system because of bow structure and place that can be given for ancoring system.
    The whole system should be light and without to many mechanics.
     
  10. DanishBagger
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    DanishBagger Never Again

    I just had a thought, that thing going from the stem: If you moved it back so the "mouth" of it was at the stem, and not the pivot point, quite a bit less force would be exerted there, if the mouth rested on the very stem, and between to "lips". Of course, it would take up a lengthier portion of the deck, but you could tip it down much lower.

    Andre
     
  11. winchgorilla
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    winchgorilla Junior Member

    Thanks on thought Andre, I will take your thinking into account and will see how this reacts with other systems on bow.
    Bow is very narrow.
    Thanks again.
    Matjaz
     
  12. Sander Rave
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    Sander Rave Senior Member

    Interresting, but demands seem a little subjective. What is light, and when will there be too little mechanics? When the anchor doesn't come up by itself?
    If you want some feed back, we need some more input ;-)
     
  13. winchgorilla
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    winchgorilla Junior Member

    I will give you more infos next week because now we have some things that we have to solve before this Eastern weekend.
    Stay you all guys in touch here till next week, it will be interesting I hope.
    Thanks again,
    greetings
     
  14. DanishBagger
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    DanishBagger Never Again

    Well, I don't think this helps much, but anyways, here's what I was thinking, you could connect a little ram to an extension beyond the pivot point, just a simple one, of course, to take the brunt of the weight. I didn't draw that, but I can if you want me to.
     

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  15. Guillermo
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    Guillermo Ingeniero Naval

    I agree with Karsten, Fast Fred and Sander Rave. The system has to be quite strong for serious anchoring, so it's gonna be really heavy (And not only the launching device).

    What kind of anchoring pattern are you expecting?

    If Al's calculator is not wrong, as per a rough estimative, asuming 16 m of 10 mm BBB link chain and the remaining rode in nylon rope, for a typical medium holding anchorage with 10 m water depth + 2 m bow freeboard, and 5ยบ rode angulation at the anchor, you may expect to manage, at least:

    - A 19 kg high holding power anchor (Not a Bruce style as in the drawings), and 95 meters of 16 mm three-strand nylon rope, for 40 knots winds (Top limit for a Force 8 gale). Dynamic loads are going to be over 1000 daN.

    - A 35 kg high holding power anchor and 109 m, 22 mm rope, for 63 knots (Top limit for Force 11). Dynamic loads over 2600 daN

    If you go for a fast setting but lower holding power anchor, like Bruce, then you should add a 30% more weight to it, at least.
    If you go for a 100% chain ground tackle, then you'll get higher dynamic peak loads and so the needing of much bigger anchors.

    Note: 1 daN = 1.02 kgf
     
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