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311/331/323 all chain rode size/length?

Discussion in 'Ask A Beneteau Owner' started by stevemitchell, Jul 8, 2018. Add this thread to a FAQ

  1. JimInPB

    JimInPB

    Joined Aug 22, 2017
    866 posts, 240 likes
    Hunter 212 & 170
    us West Palm Beach
    +1
    Most of my (non-windlass) anchors are set up as kits, with anchor, chain, line & a float in a bucket or crate. I'm another guy who likes to keep the option of ditching the anchor quickly & coming back for it later if need be. Sometimes things just happen & require that you respond quickly, like when the 50' trawler, that was on the ball up-current from you, slips his mooring line off the cleat & goes for a drift with zero warning in a 3 knot current in the ICW at half tide.

    But most of the time when I ditch an anchor, it's just because I hooked a big fish on lite tackle & I need to chase the fish down before I get spooled.
     


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  2. jssailem

    jssailem

    Joined Oct 22, 2014
    5,594 posts, 1,892 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    @stevemitchell I sail in the Sound and north into the Salish Sea. I just went through the eveluationstage And selected the following. Boat... 35 ft 15000 pounds displacement.. suggestion among anchor manufactures was 3 tomes your waterline in chain. The 1.5 to 2 times the amount of nylon rode.
    I bought 105 feet of HT chain and 200 feet of nylon plait rode. I am installing a Lewmar V3 with captain windlass. Mantus Anchor. 35 Lbs and Mantus roller. I Cary another 50 ft of chain attached to 150 nylon 3 strand as a back up for my Danforth.. I have a Bruce 33 lb. with 90 feet of chain that I just removed from the boat.
    @LeslieTroyer has tried the Mantus out and is pleased. Only issue was when the anchor lands in an abandon crab pot. The holding power goes way down.
     


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  3. Captain Larry-DH

    Captain Larry-DH

    Joined Jun 14, 2010
    353 posts, 122 likes
    Quorning Dragonfly 1200
    US home
    Your response missed the point you were answering. If you read Alain Poiraud‘s book or articles you will understand the engineering science that proves rope/chain provides far superior holding because the peak snatch loads on the anchor will never be as high as all-chain.
    It explains why any catenary effort is only helpful in the milder conditions when it’s less important, and it doesn’t really take as much force as people may think before the chain goes bar tight.
    Edit: So all else equal your point about new gen anchors and scope is valid, but all-chain is not equal to mixed rode.
     


    Last edited: Jul 10, 2018
  4. thinwater

    thinwater

    Joined Mar 26, 2011
    1,891 posts, 325 likes
    Corsair F-24 MK I
    US Deale, MD
    Yes and no.

    If the water is very deep (over 25 feet) the amount of chain required to create ~ 5:1 scope will maintain significant curve up to 35-40 knots. Once you have >200 feet of chain out it gets hard to lift off the bottom and hard to straighten. It is in shallow water where chain straightens easily and the ride gets rough. I've tested both, and the math and cruiser experience support this.

    You can use a long snubber (30-40 feet) with chain. This will solve the snatch load problem. This is a very common solution that often provies the best of both worlds (no cutting and good shock absorption).

    This is one aspect of Poiruad's book that shows his personal predjudice against all-chain. He just does not like it. I suppose it is a reaction to the mythical status of all-chain in many circles. The truth is that it is a continuum, with all-chain as the right answer for some boats and some areas (long and short snubbers as needed), and mixed rode for smaller boats in less rocky areas. I've used both types and they each have advantages when properly applied.
     


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  5. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    2,608 posts, 1,090 likes
    O'Day 19
    US Littleton, NH
    Part of the issue is the comparison of all chain according to the standards for all chain vs the standards for rope rode. 3:1, 4:1, 5:1 will have a different effect on the pull angle when no catenation is considered. But, 7:1 is 7:1 in an anchor no matter what the rode is made of. In terms of losing set, as has been pointed out above, any anchor could lose its set. What is more likely to reset that anchor quickly? I'm in favor of all chain when it is affordable both in dollars and in displacement. However, a mixed rode will likely serve all the needs most of us will ever have if everything else is well handled. Remember, also, in severe conditions, depth of water changes enormously, so 7:1 in 35' (245' of rode) may become a momentary 6:1 in 40' at the peak of a 10' wave.

    - Will (Dragonfly)
     


  6. Captain Larry-DH

    Captain Larry-DH

    Joined Jun 14, 2010
    353 posts, 122 likes
    Quorning Dragonfly 1200
    US home
    @thinwater you are right to bring up the distinction between catenary and depth. And Poiruad does clearly bring that out as well. I think he stays somewhat neutral on that point.
    However, 30-40 knots of wind and <25 foot anchorage depths are not an unusual occurrence in anchorages. Pretty typical for most of us to encounter at least a few times per year, and when that all-chain rode goes bar-tight it's not really ideal to count on an anchor's resetting capability. (I'd rather the anchor see lower peak snatch loads, and have the anchor stay buried.)
     


  7. jviss

    jviss

    Joined Feb 5, 2004
    2,603 posts, 258 likes
    Tartan 3800
    US Westport, MA
    I can say with engineering certainty that the chain never goes "bar tight." To straighten out that length chain completely would require enormous force, more than you'd see anchoring. "Bar tight" is a myth. Because of the weight difference I would expect rope to straighten with much less tension than chain. It looks straight when you are only looking at about 15' of it going into the water.

    I have a lot to say on this topic, but for the moment, in terms of ruggedness and service life, in up to 20' of water on a 36 or so foot boat, you can't beat 100' or so of 5/16" chain to a 33 lb. Bruce. Use a snubber, a long one, if you're really concerned about shock/snatch loads - depends on the waters and how your boat rides at anchor.

    I haven't cruised extensively like many here have, but I've ridden out 50/55 kt. gales anchored in 8' to 12' of water in the Great Salt Pond on Block Island. Saw lots of boats drag. Never me.
     


  8. stevemitchell

    stevemitchell

    Joined Jan 12, 2016
    134 posts, 6 likes
    Beneteau 311
    US Seattle, WA
    Thanks for everyone's feedback. As ever, whenever I research anchors, anchoring, rodes, and the like, there are tons of opinions and data to be parsed before making a decision.

    Given my boat size (32', around 10,000 lbs) I am leaning towards this design:

    Rode: 100' 5/16" G4 chain + 200' 5/8" 8 plait nylon rode
    Maxwell HRC FF 8 Windlass

    I am not considering an all-chain rode given the weight and that I would most likely be using between a 3:1 and 5:1 scope for most common anchoring, with the need for 7:1 only in extreme conditions.

    The rode selected is an upgrade to what I have now both in length and size of chain, as well as overall length. Based on feedback in the above thread, I think this is a good balance of chain length/weight to holding power, and should improve things considerably.

    The windlass choice was after a lot of research. So far I prefer Maxwell given that their support seems very good, and they have options I might consider adding such as a wireless remote and the like.

    I originally started with the Maxwell RC6/8 models which are vertical windlasses, but the space underneath required for the motor may not work out. Additionally, the angle at which my rode comes in off the bow roller exceeds their 6 degree limit, which would require a ton of additional shim work.

    The HRC FF 8 is a horizontal windlass, and while I understand the 90 degree touch vs the 180 of a vertical, it just fits far better in the space I have available, and I believe would feed better from the bow. The HRC 8 also has almost 200 pounds more pull than the RC series of similar size, so that's nice.

    The only thing that is unclear is whether the HRC FF 8 actually supports 5/8" rope. The specs online say it only supports 9/16" (14mm) which is odd, and other places say it supports 5/8" (15mm) as well as some reviews. It is essentially a horizontal version of the RC 8, which originally only supported 9/16" but now supports 5/8" so I would guess the HRC does too, but would rather not base an entire rode decision around that.
     


  9. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    2,608 posts, 1,090 likes
    O'Day 19
    US Littleton, NH
    Stevemitchell,
    You have calculated the weight of 1/4" chain to be just under a pound per foot. I feel 1/4" borders on the light side, but will probably work just fine. Is that what your current 30' of chain is? If so, it has proven itself to be adequate. All you have to pull by hand is the weight of chain represented by the depth you are anchored in, plus anchor. Your 30' lead chain plus anchor probably represents that already, so there shouldn't be any additional weight to pull by hand. If you are looking at hand pulling in > 40' feet of water, invest in a windless.
    Have you said what your anchor is and its size?

    - Will (Dragonfly)
     


  10. JimInPB

    JimInPB

    Joined Aug 22, 2017
    866 posts, 240 likes
    Hunter 212 & 170
    us West Palm Beach
    The issue of a chain pulling nearly straight can be mitigated by using heavier chain &/or a chum weight (aka sentinel weight, angel weight, etc).

    That aside, I've always had good luck with a combination of chain & line. I have never felt the need to have more than 100' of chain on a boat that was less than 50' unless you were going to sharp jagged rocky areas. That is just my preference though. A lot of full time live aboard types carry more chain & swear by it.
     


  11. jviss

    jviss

    Joined Feb 5, 2004
    2,603 posts, 258 likes
    Tartan 3800
    US Westport, MA
    Kellet.
     


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  12. thinwater

    thinwater

    Joined Mar 26, 2011
    1,891 posts, 325 likes
    Corsair F-24 MK I
    US Deale, MD
    This is mostly right. In shallow water (4-6 feet), with a cruising cat, with light chain, in a 60-knot thunderstorm, the chain is effectively straight. You have 1000 pounds of tension and perhaps 75 pounds of chain out--obviously, there's no meaningful curve. Pull out your come-along and see. But this is an extreme case.

    You can either do the math or dive; I've done both. In 20' at 5:1 scope it will take about 50 knots to lift the chain off the bottom. Less scope will take less wind. On the other hand, it only takes about 30 knots to get the chain so straight that it loses all meaningful ability to absorb shock (there is some curve, but the difference between straight-line length and actual length is only a few feet). In shallow water this happens at about 30 and 20 knots, respectively, depending on a few variables. This assumes you are using properly sized G4 chain; if you use heavier chain that shifts the numbers a little.

    Then there is the question of whether an anchor can actually withstand up-lift. The answer is yes, but it depends on the soil type and the anchor type. Without digging into the test results, most anchors lose about 50% of their capacity at 5:1 actual scope (as if you used rope) at the bottom. Maybe that is enough. Maybe the soil will start to liquefy.

    There are a lot of variables. Some folks think 30 knots is a lot of wind. Some think 7 feet is deep. No one answer. Curiously, it seems to be middling depths (8-12 feet) that give the most trouble; people try short scope, a thunderstorm comes up and starts some hobby horsing and yawing, and out pop the anchors. In deep water you tend to have a lot of chain out, and shallow water long scope is easy.
     


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  13. jviss

    jviss

    Joined Feb 5, 2004
    2,603 posts, 258 likes
    Tartan 3800
    US Westport, MA
    That's a lot of rope. I prefer three-strand, but I understand plait stows better.
     


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  14. jviss

    jviss

    Joined Feb 5, 2004
    2,603 posts, 258 likes
    Tartan 3800
    US Westport, MA
    Me too! But I confess I haven't dove when it's blowing 20+ kt.
     


    Last edited: Jul 11, 2018
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  15. stevemitchell

    stevemitchell

    Joined Jan 12, 2016
    134 posts, 6 likes
    Beneteau 311
    US Seattle, WA
    @Will Gilmore - in my last post I have moved to using 100' of 5/16" chain, which is close to equal in weight to 150' of 1/4" chain.

    My current rode is 15' of 5/16" chain + 150' of 5/8" rope, and a 33 pound Rocna anchor. I can easily pull it back onto the boat, but 15' of chain is far too short for my liking.

    The current plan is 100' of 5/16" chain + 200' of 5/8" rope + 33 pound Rocna anchor and a Maxwell HRC 8 windlass.
     


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  16. stevemitchell

    stevemitchell

    Joined Jan 12, 2016
    134 posts, 6 likes
    Beneteau 311
    US Seattle, WA
    Yup, rope is pretty inexpensive, and that gets me to a 40' anchor depth at 7:1 scope if I ever need it. I tend to plan for worst case scenarios as much as possible so I don't end up wishing I had more at an inopportune time :)

    I've actually never used 8 plait, always 3 strand, but from my research 8 plait appears to work about the same in a rope/chain windlass, but stows quite a bit better. I know from hand flaking things that 3 strand can be a bit of a pain...
     


  17. LeslieTroyer

    LeslieTroyer

    Joined May 20, 2016
    1,609 posts, 533 likes
    Catalina 36 MK1
    US Everett, WA
    The boat came with 15’ of 5/16 and 250 of 8-plait on a Bruce 15kg. I switched to Mantus this year with 120’ of 5/16 and 250 of 8-plait. I hook on a Mantus bridal that has a total of 4 bungies and adds about 15’ to where I clip on. So far very comfy. Worst conditions was sustained 30kts gusts to high 30’s in 20’ of water 90’ total deployed length. I slept like a baby and only problem was picking up the anchor when it was time to leave
     


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  18. jviss

    jviss

    Joined Feb 5, 2004
    2,603 posts, 258 likes
    Tartan 3800
    US Westport, MA
    Well, it's only 1/2 what the chain costs, per foot. At Defender 5/8" 8-plait from Yale is $1.70. 5/16" G4 is $3.40.
     


  19. Captain Larry-DH

    Captain Larry-DH

    Joined Jun 14, 2010
    353 posts, 122 likes
    Quorning Dragonfly 1200
    US home
    8-plait is a joy if you have a windlass because it falls straight down into the locker and stows in less than half the space of equivalent 3-strand. It’s a little more stretchy. I think the downsides are price and it’s more likely to snag strands on other objects.

    As for kellets: imho they complicate deployment and retrieving, and they are only really effective at preventing a boat on rope rode from meandering aimlessly when the wind dies to zero. ( I think you’re better off putting that extra weight into the anchor, if it’s holding you want .)
     


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  20. JimInPB

    JimInPB

    Joined Aug 22, 2017
    866 posts, 240 likes
    Hunter 212 & 170
    us West Palm Beach
    Thank you. That was the other name that I couldn't remember when I was typing.
     


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