How much space to allow for anchor rode?

Discussion in 'Metal Boat Building' started by pdwiley, Apr 13, 2012.

  1. pdwiley
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    pdwiley Senior Member

    Assume 60m of 10mm chain on one rode and 100m of 16mm multi-braid with say 10m of 10mm chain on the other. Boat displaces 15500lbs so the sizes seem ample to me.

    How much space is this going to take up?

    What's the best shape to dump it in?

    I've sufficient brains to feed the rodes into separate compartments so they don't tangle.

    I also have some nice heavy walled black poly pipe approx 400mm diameter in search of a use as I got it for free. Occurred to me that it might make a nice receptacle for the rodes if I can find someone to weld plates on the bottom.

    Thanks.

    PDW
     
  2. Stumble
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    Stumble Senior Member

  3. Frosty

    Frosty Previous Member

    Have you? well trying to force it into 2 recepticles will no doubt achieve the very tangle you are trying to avoid.

    A pyramid shape is what you will get, wether you like it or not.

    First in last out OR last in first out-- try to stop that and you will get a tangle
     
  4. michael pierzga
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    michael pierzga Senior Member

    Chain piles up in a Pyramid form. Construct your GRP chain locker as a tall pyramid. Make the top narrow....just enough to get your arm in the box...then drill and drive a stainless steel rod or two across the mouth of the box to keep the chain from escaping the box in case of a knockdown.

    Water will always flow down a chain and spoil your forepeak bilge. Keep the water in the chain box. Double bottom the GRP chain locker and instal a small dedicated chain locker bilge pump to empty the box...protect the pump with screen filters.

    I will measure a succesfull one hundred meter 10mm chain, grp pyrimid box recently intalled and post.
     
  5. michael pierzga
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    michael pierzga Senior Member

    As a rope rode I use yacht double braid of the appropriate diameter. Typically you must handle this rope rode with a self tailing winch...multi plait rope doent like to self tail. The diameter of your rode must be suitable for your winch. I re spool the rode after use .

    I would also go with 100 meters of chain if it will fit in your forepeak.

    A stand aside second chain box to hold 40 meters , with 60 meters in your primary box is workable. Many times I lay 100 meters of chain. Many times I wish I has 200 meters of chain. Generally in heavy conditions the best holding ground,,, is to windward, free of other boats and ubstructions.... and is in deep water...20 meters or more.
     
  6. michael pierzga
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    michael pierzga Senior Member

    an anchor detail to keep you boat dry when at sea it to disconnect the chain from the anchor and drop the chain into the box.

    To close off the chain pipe hole and keep water out, thread the bottom of the pipe as it enters the chain box and screw a cap on the chain pipe. You can take hundred...thousands of liters of water thru the chain pipe on a long beat to windward.

    Weld a small eye on the inside of the pipe cap so that you have a messenger line to re run the chain.
     
  7. Stumble
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    Stumble Senior Member

    Anchor lockers should drain overboard, not into the bilge. Covering the hawser pipe isn't a bad idea, but it isn't necessary if properly drained.

    Secondly pyramid shaped lockers are a bad idea, you want to minimize the amount of contact chain has with the interior of the boat by making the locker into a cone, not maximize it by encasing it. This also allows you to add more chain later, introduces air to help dry out the locker, and reduces maintenance from reprinting the locker.
     
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  8. Frosty

    Frosty Previous Member


    Quite right --I just could not be bothered to type it out.
     
  9. CatBuilder

    CatBuilder Previous Member

    +1 for stumble.
     
  10. michael pierzga
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    michael pierzga Senior Member

    I have no idea what these guys are talking about. A chain box can only be self draining if its base is above sailing water line. To be self draining implies that 100 meters of chain is literally stored on deck. not good, aside the weight on deck , chain needs a minimium 250mm fall from the gypsy or it will pile up.

    Chain naturally piles in a Pyramid. Be my guest to make a cone shaped box.. a 4 sided pyramid is easier to construct. .

    Ive never painted a chain box...its made of fibreglass and lined with rubber sheet to deaden noise. .

    The box shown is a flat backed pyramid, 950mm tall with a 100mm chain sump , 500mm at the base and 200mm at the neck. One hundred meters of 10mm chain is stacked in it ,,the stack of chain is 750mm tall. the box functions flawlessly.

    Mount your winch and chain box as far aft as possible on your boat. Against the forward waterproof bulkhead is ideal.
     

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  11. TeddyDiver
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    TeddyDiver Gollywobbler

    :confused: Me thinks that's about as far fore as possible.. anyway if you want it below waterline.
     
  12. Frosty

    Frosty Previous Member

    I think we are all thinking different sized boats. The picture of the winch is the only guide to how big the boat was/is.

    555 are usually up to 40 foot.
     
  13. TeddyDiver
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    TeddyDiver Gollywobbler

    Metric formula for the locker (from D Gerr Boat Mechanical Systems Handbook)
    Chain-locker volume in m3=m of chain x (chain size, mm)ˆ2 / 48,612
    and
    Rope-locker volume in m3=m of rope x (rope dia. in mm)ˆ2 / 481,62
    BR Teddy
     
  14. pdwiley
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    pdwiley Senior Member

    Thanks. I've got that book, have to pull it out and have a read. Was hoping for a pragmatic answer from someone with a similar sized rode.

    FWIW it's a 12m sailboat. No chance I'll drain the chain locker overboard because I don't want it that high up. It'll either drain into the fwd bilge or the water can evaporate out of the chain/rope bin. Not sure which will work better but I've provision to run a drain line straight to the fwd bilge recess so it really doesn't matter, I can do either or both.

    PDW
     

  15. Frosty

    Frosty Previous Member

    Your formula is fine but heres a better one. Make your anchor locker as big as you possible can. So big that it would need a total re design to make it bigger.

    By doing that you should get it right first time.
     
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