Wire Rope Anchor Rode

Discussion in 'Boat Design' started by Pauls, Aug 30, 2010.

  1. Pauls
    Joined: Jul 2010
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    Pauls Junior Member

    I'm designing the anchoring gear for a 42' cutter I'm building. I'm interested in the use of wire rope as a replacement for chain. It's 1/4 the weight for the equivalent strength of G40 chain and costs 1/3 as much. Storing it tangle free on a drum sounds appealing.

    I'd like to hear feedback from any members that have experience with wire rope as an anchor rode. In particular, what is effective at protecting it from corrosion (grease?), and how well it holds up in use.

    Regards, Paul
     
  2. Easy Rider
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    Easy Rider Senior Member

    Pauls,
    Some fishermen use it here in Alaska on their drum winches but I've heard very little about how well it works. Could be the key element in an ideal anchor rode in that it would certainly come close to providing ideal weight distribution to bring about the most effective catenary possible. A very short length of super heavy chain of about 3' followed by 8 to 15' of heavy chain followed by wire would keep the anchor shank down so the anchor will provide it's best performance. Given enough swinging room one could have a very long scope.
    I would think a level wind and some kind of tensioner would almost be required for seamless anchor retrieval. Remember the trailer boat winches w wire on the winch? What a mess. That could be the reason wire anchor rodes are not very common.

    Easy Rider
     
  3. Submarine Tom

    Submarine Tom Previous Member

    At 1/4 the weight of chain, this is a huge disadvantage.

    Part of the benefit of having weight next to your anchor is to keep your angle of attack low there-by simulating a greater scope.

    This helps keep your anchor embedded in the sea floor. The weight also acts as a shock absorber while the hull takes

    wave action and surge on the surface.
     
  4. alan white
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    alan white Senior Member

    Chain has weight. Otherwise, we'd all use rope instead. Wire rope is relatively light. In addition, it does not coil unless it is twisted 360 degrees with each coil laid down. It would have to flake or lay down in a figure eight.
    Chain on the other hand has so much rotational freedom that it lays down perfectly.
    You could use a big reel to store the steel rope, true. Maybe just under the deck. But the reason nylon is used for rodes is that it stretches a lot, which is exactly what's needed to prevent shock loading. The chain does the same thing by lifting its weight with an effect similar to stretching.
    It's the weight of the chain that helps to set the anchor, causing the anchor to pull horizontally.
    While wire rope may have some limited use anchoring, I don't know if it would be useful on a 40 ft sailboat.
     
  5. FAST FRED
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    FAST FRED Senior Member

    For boats that anchor overnight with no deck watch, chain or chain/rope would be safer than wire rope.

    In a gust the boat will surge back , the Wire rope has tiny catinary so transfers the load directly to the anchor.

    Chain will lift and need to be dragged along the bottom, lowering the forces on the anchor .

    Probably the "best" is half chain , half properly sized nylon
    (Anchors and Anchoring.. Van Dorn)

    This seems to give the best results , esp if anchoring in deep (over 100ft for most) water.

    FF
     
  6. apex1

    apex1 Guest

    The combination of chain and high tensile rope is a proven compromise when a anchor weight is attached. But thats more often than not a mess on the windlass capstan / chain wheel. And the anchor weight is another part to handle and store.

    When you have no problem with weight, the chain is still the best solution.

    Regards
    Richard
     
  7. skypoke
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    skypoke Junior Member

    I know that Brent Swain, the fellow who designs the origami sailboats, specs wire rope and a hand operated windlass on his sailboats. He claims good success with them. As long as you have a decent windlass/fairlead arrangement and a good chunk of heavy chain at the anchor, why not? Good quality galvanized wire rope will last for years.

    Chuck
     
  8. Easy Rider
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    Easy Rider Senior Member

    FRED,
    Yes, I forgot about the stretch factor. All things considered wire rope dosn't sound like a good solution. I use that new anchor line called "Brait". LIke it very much.
    skypoke,
    I agree. I think the chain should be the smaller part at the anchor end.

    Easy
     
  9. FAST FRED
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    FAST FRED Senior Member

    I think the chain should be the smaller part at the anchor end.


    Something to think about for the folks that prefer a nylon rode , the short chain can be way over sized ,since it need not go thru the chain gypsy.

    It MUST fit thru the bow roller , but if it stops short of the windlass/capstan , a fine heavy size can be used.

    Actually wire rope is an ideal solution for the fish guys.

    They frequently anchor , move , anchor , move and the wire can be remotely dropped or recovered from the pilot house.

    Since there working , dragging is of little concern , its just a slow way to a downwind spot.

    FF
     
  10. mark775

    mark775 Guest

    Wire lasts far longer than fiber rope and has a smaller diameter than all but the spectra ropes. It is used all the time here with good success but one still needs chain for catenary (chain - catena - catenary) and for chafe resistance. It lays nicely on a winch and with a little guidance (a prying point and a bar in front of the winch), it will lay perfectly.
    The smaller diameter comes into play when anchoring in current in deep water for some fishing operations. A wire roded boat will stay on a delicate hold in more current (because of the smaller diameter) than fiber ropes and weighs less than all chain. The touted stretch of nylon is insufficient to do anything positve - Nylon is used because it sinks, is strong, doesn't much degrade, and somebody said its stretch will keep your anchor from pulling. That being said, the stuff Easy uses is good for small boats but one still needs chain.
    Spectra (UHMW, Dyneema is slightly better/more expensive) fibers have almost entirely replaced wire on winches here because of the tangle problems with wire Easy mentioned. I have anchored in deep water with an added shot of spectra and it worked very well. My personal preferred set-up now for a forty foot boat or so is; as much chain as one feels he can afford in weight (maybe 60' of 3/8" - I use only 25 feet of 5/16" because I anchor in rocks with very little scope but I have a bigger anchor/more,heavier chain onboard.), several hundred feet of nylon (consider it expendable and the only part that wears and needs replacement every few years unless you break an anchor), then the rest in spectra rated higher than the nylon - If it ever were to part (if I get a little fray near the bottom of the rode from a rock, I leave it - that way, when it parts it will be near the bottom and all I have lost is anchor and chain - remember I am in rock 90% of the time. The bugger is re-eyeing the double braid nylon after it ages.), the nylon would serve as your weak link, the nylon will be used a vast majority of the time, and when you fish in 600' or in a 2knot current in 200', you'll appreciate the spectra, which was kept nicely out of the sun by the covering of nylon on the winch.
    I wouldn't use wire on a windlass and one wud need a large diameter head to accomodate it anyway. Spectra works well, flakes well, but requires more wraps to keep from slipping.
     
  11. Easy Rider
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    Easy Rider Senior Member

    Mark,
    Excellent post. Interesting about the current. One can learn from stuff like this. So your'e in the rocks up there eh? Mark ...what type of anchor do you use and do you have any tricks or info for short scope work? I use the Brait line cause it always comes out of the box just as easily as it went in. They say with a properly sized anchor and rode the rode will become straight, without catenary before the anchor rips out. That would mean the catenary is really only good for setting and reducing shock load for long periods of cyclic pulling (as in waves overnight). It appears that without the waves one would be as well off w a super light but strong enough line and say "who needs catenary"?
    There seems to be endless angles for anchoring.

    Easy
     
  12. mark775

    mark775 Guest

    Well, Easy... When fishing, I anchor two to seven or eight times a day but the techniques I use are contrary to secure anchoring (staying put overnight, e.g.) in typical conditions. Solid jagged basalt holds amazingly well. When in rocks (basalt or coal/shale, jagged), I minimize the scope, usually just 1 1/2 to 1 and the anchor will find a home almost intantly that will not pull out until pulled forward on. Danforths, Fortresses, etc. are one-time use in this circumstance, expensive anchors (CQR, Bruce) are a waste, tho I used Bruces or a Davis SeaHook/Furfjord with a break-away until Lewmar started importing the cheap Chinese junk. The cool thing about these lousy anchors is, tho I feel guilty using them and they are ugly, they will break if you really reef on 'em and you save your chain, the store gives you a replacement (until they catch on - try Redden Marine in B-ham), and they are cheap enuf that anyone can afford spares. Their breaking propensity is reliable enuf that a break-away tie-up is unneccessary and, in fact, undesirable as it makes your hold less stable - simply use a little heavier rode than otherwise (I use 3/4" Sampson Braid @ nom. 19,000lbs. and add 7/16 Amsteel Blue Dyneema @ 21,00lbs.) and pull forward and at an angle and the anchor shud break if badly hung (40', 18,000 pounds). Letting the chain and rode get wrapped up in rock will get more expensive. Much scope is bad here.
    Of course, anchoring anywhere else will entail conventional technique. These type anchors hold nowhere near as well as Danforths and such in sand, clay (the best holding if you can find it) or gravel.
    When the Chinese learn to copy metalurgy as well as shape, the anchors will no longer be as good!
    I think I remember a pic of your boat and somthing like 7/16 soft stuff like you mentioned (the stuff that doesn't tangle easily - I've read about it), 20 ft. of 1/4" chain and a ten kilo Lewmar (Jokingly refered to as "Bruce Lees" - playing on the quality Bruce anchor name). Have another 30' of chain available and a 15 kilo "storm" anchor and you can anchor in less ideal conditions, as well, but I doubt your boat will easily break the 15 if it gets hung. Lotsa rode is for sand. It's better to leave an anchor and get it in nicer conditions than it is to risk trying to break in rough water (I'm saying for other reader's benefit - I know you are aware).
     
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  13. marshmat
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    marshmat Senior Member

    There's a 61 metre car ferry near here that has wire rope anchor rodes. She has a Navy-style anchor on each end, then about 4-5 metres of very heavy chain, then wire rope of about 2.5 cm diameter. I'll take a closer look next time I go to the island.

    Wire rope won't flake down in a locker. But stored on a drum, it might work very well. Take a look at the winch drum of a tower crane next time you're at a construction site- a similar design might work for anchoring applications. You'd need guides of some kind, possibly like those on a baitcast reel, to stop it from forming rats' nests on the drum.

    Attaching a snubber or bridle to a wire rope anchor rode could be difficult. Ideas?

    As for weight- the advantageous catenary effect approaches zero as the wind picks up, which is exactly when you want the holding power at its best. An extra kilogram in the anchor itself has a much greater effect on holding power than an extra kilogram in the rode. For a given maximum total weight of the ground tackle system, I'd prefer to put as much weight as possible in the anchor and relatively little in the rode.

    Chafe resistance in the 10 metres or so closest to the anchor may be a factor to consider..... I don't think wire rope holds up as well as chain when chafing.
     
  14. Easy Rider
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    Easy Rider Senior Member

    Another excellent post and I learn again. I was wanting a Manson Ray (the better part of $1000) but decided on the Plastimo Manta ...cheap by comparison. I see some claw anchors on fish boats in Craig that are bent. I didn't know the metal in those things was that malleable. It's interesting that the Lewmars actually break. At least you get your rode back.Perhaps the bent one's are real Bruces. Despite all the talk it seems the claw anchors do work very well. My Brait is 5/8 and I've got 350' of it so I could afford to loose some so the sacrificial anchoring you refer to may (to some extent) work for me.
    marshmat. Exactly my thinking .....put the weight in the anchor.
     

  15. thinkubuntu
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    thinkubuntu New Member

    Just to finish this very old thread in case anyone is reading this who may not be familiar with anchoring / rode selection. Unless you know exactly what your trying to achieve and are not looking for a general purpose anchor rode then wire rope is completely impractical and a terrible solution for the proposed boat.

    It is not however a failure of weight, for as mentioned by a previous poster the catenary effect of a chain is near zero when the chain is tight. That said weight next to the anchor (a previous poster said a heavier anchor though this may be convenient it is misleading the important weight is to keep the angle from the rode to the anchor as low as possible so ideally the weight should be directly attached to the anchor but flexible that it has to be lifted before pulling on the anchor itself, this being the ideal, of course if you put a big enough weight be it an anchor or a lump of concrete anything will work but that is impractical for the use mentioned)

    Second the reason people use mixed rode is that it is the rope section of the rode (nylon or polyester) that allows the rode to stretch and this has a far greater effect on the ability of the anchor to resist surge loading that is the normal cause of failure and weight for weight much lighter than chain and normally any rode, no matter what length is benefited by having a rope leader.

    A wire rope would need special equipment to retrieve, and should this fail it would be all but impossible to pull in an anchor on a wire rode, believe me it's hard enough to pull rope or chain but on a 42` boat it would be far easier to pull 20+mm rope than a thin wire rope, especially if you like to keep your fingers attached to your hands!

    The only solution that a wire rode may be suitable is for the first meter or 3 or a combined anchor rode that terminates at a Danforth anchor and this is only to make a smaller surface area of the rode leader that it can penetrate the sea floor more easily )theoretically)

    There are many great resources on anchoring, books or even online, Rocna for example have a very well summarised information on just the above points and well worth a read to understand the forces at work in anchoring.

    Just in-case anyone responds by pointing out that it could work if such and such, I say this, on the right day I could anchor my boat with a piece of fishing line and hook attached, but that day isn't the worst I should expect and it is that you should consider when talking of anchoring, and when one considers the tonnes of force - yes tonnes at the bow roller, would you think for a minute of putting your hands anywhere near a wire rope holding that force? and if you trust your (gear) to pull it up for you, your experience of the reliability of equipment in the marine environment functioning 100% of the time has been much more positive than my own!
     
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