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Old 17-08-2008, 10:00   #1
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Anchor rope size, advice sought

Just returned from cruising W. Scotland, during which it became apparent that I need to carry more than my present 45mtrs of rope backing my 30mtrs of 8mm chain (I don't want to carry more chain). The gypsy is a combined rope & chain type and can take 12mm or 14mm 3 strand nylon. I'd like to use 12mm as obviously more of this would fit in the chain locker. Question is: do I need the extra strength of the 14mm? Boat is a Sarum 28: a fairly bulky 28 footer with probably above average windage. Anchor is a 10Kg delta.

8mm chain breaking load 3200Kgs, s.w.l. 1600kgs
12mm 3 strand nylon breaking load 2900kgs
14mm 3 strand nylon breaking load 4000kgs
The rope's theoretical strength would be reduced by splicing and inevitable abrasions.
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Old 17-08-2008, 10:04   #2
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Here is a place to start
anchor rope rode - Google Search
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Old 17-08-2008, 13:57   #3
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breaking strain, especially when it is weakened by splice demands that you use 14mm in order to match it against the chain.

In order to make it MUCH easier to stow, and much easier to handle, use octoplait instead of 3 strand.

This will stow in a much smaller space, and avoid the kinking and terrible problems of stowing 3 strand.

It is also much easier to splice to chain, giving you a stronger connection as well.
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Old 19-08-2008, 10:03   #4
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Quote:
Originally Posted by Talbot View Post
breaking strain, especially when it is weakened by splice demands that you use 14mm in order to match it against the chain.

In order to make it MUCH easier to stow, and much easier to handle, use octoplait instead of 3 strand.

This will stow in a much smaller space, and avoid the kinking and terrible problems of stowing 3 strand.

It is also much easier to splice to chain, giving you a stronger connection as well.
I know 8 strand is much easier to handle but my windlass has a single gypsy that handles both rope and chain, but according to the manual the rope has to be 3 strand.
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Old 20-08-2008, 02:56   #5
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Jim - Your chain DOES NOT have a SWL of 1600kg, it is only 800kg. The 1600kg is it's Proof Load which is twice it's SWL. It is a Grade L or what was called a Grade 30. It is important you don't confuse the 2 loads.

It works like this -
Break load is XX
Proof Load is 1/2 XX and the actual load that is applied in the factory during the testing process.
SWL or WLL is 1/4 XX or 1/2 of Proof load.
There is the odd exception to that, US 'Hi-test' being the more common in anchor chains but generally outside of the US everyone else uses the above.

The match for almost every single winch that runs a 8mm chain is a 14mm rope. Going to 12mm may very well just slip under load. It all depends on which winch as to which rope is best to use. All will run 3 strand but not all will run a Octiplait.

Generally (and I mean generally as there is some quirks)
Verticals - Maxwell runs everything as does Lofrans and Quick. Lewmar say they can run octiplait but it is well known often they just don't work. Anchorlift = 3 strand only as is Muir. The guys with 3 strand only winches are working ahrd to get both but as yet they are not proven.

Horizontals - generally 3 strand only.

If you can give me a manufacturer and modal I'll suss my database for you.

NOTE: many winch manufactures publish numbers which just don't work well and some are just complete crap. This is an issue I've bitched to most of them but many just don't seem to care.

Octiplait is good for stowage but equally some 3 strands are as well. It all depends on the rope quality. Just like anything there is good and bad ropes. A bad octiplait will give greif as will a bad 3 strand. It is highly recommended you buy a top end quality rope made in Japan, the EU or the US. While there is some dodgy stuff there they are generally massively superior than those from elsewhere. You will note I said 'made in'.

For example a Samsom Pro-Set 3 strand performs very very similar to a quality ocitplait and even when talking stowage.

Spend the time and the money to get a rope made from Type 66 nylon fibre. That has far higher thermal stability than most ropes on the general market, it is also the grade used in car airbags.

Most commonly sold ropes are only T6 grade or some cheapies only Textured nylon, textured is reject from making the clothing industry and shouldn't be in the marine industry at all. The biggest difference it the Thermal Stability. You've seen those hard wire like nylon ropes? That happens with age and in relation to their thermal stability. Higher the thermal stability the long it takes for the rope to go bad on you or more specifically your winch. Auto Rope to Chain winches just don't like hard stiff ropes and you have probably noticed stowage isn't flash either.

And while it may hurt the wallet a bit, think of it this way -
You buy a rope for $1 a mt and it lasts 2 years and gives some grief. being a bit generous here, we've seen some of these stop working in as quick as 4 months.
You buy a rope for $3 a mt and it lasts 10+ years and usually doesn't give greif.
Which is the better deal??

I know your wallet maybe twitching about now but let me assure you this is not theory, it is well proven over many many years. I make on average 15 rope to chain rodes a day and have done since the first recreational Rope to Chain winch came out 15 years ago (there abouts), which just as a FYI was by Maxwell. Hence all of the above is very very much a 'been there, done and seen it all' based post.

What's the winch?
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Old 20-08-2008, 04:19   #6
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See the NACM (North American) “Welded Steel Chain Specifications” at:

http://www.nacm.info/Downloads/NACM_Welded.pdf

Specifically, the tables starting on page 8.
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Old 20-08-2008, 17:22   #7
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Thank you for a very knowledgeable & helpful reply. My windlass is a South Pacific 800F, their website is at http://www.southpacific.com.au/old/AnchorWindlasses.htm. At present I have 12mm 3 strand backing the chain and the gypsy handles it without slipping except at the splice which sometimes rides out of the gypsy's serrations and slips under load. It's the kind of splice where the strands are threaded through the last link and spliced back into the rope. I've re-made it a couple of times without improvement. I've thought of trying the splice where the strands are spliced into the chain similar to what one does with octoplait. Do you know which of the rope brands available in the UK satisfy your quality requirements? e.g. English Braids, Liros, Marlow.
Regards & Thanks in Advance
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Old 21-08-2008, 02:01   #8
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Ahh.. the old Sth Pacific trick, naughty of me to forget that one, especially as it's based in the West Island of NZ

DON'T do the down the chain splice. That is some weird UK only thing and is known by most, inc the manufacturers, as 'The Winch Killer'.

And stay 3 strand, the Sth Pacifics have had a very chequered performance on Octiplait. Everyone here has given up trying now and runs a good 3 strand only. Careful about what the Aussies say as their marine market is a fan of 'Silver' anchoring rope. No-one in their right mind should use that crap, it's worse than shocking and can be bloody dangerous. They seem to have little clues sometimes and that includes playing Rugby (guess who just thrashed them.... again)

OK Jim try this. Resplice the chain to the rope using the back splice method. Nice clean end link of chain. 2 strands in from one side end the other from the other. Put in 2 full tucks with all 3 strand then pull firm to tight so as to minimise any movement between rope and chain. Don't have to go silly as it will tighten a bit more once in use. Then put in another full tuck so each 3 strand have 3 full tucks. Cut out 1/3 of each strand and do another 2 full tucks. Then cut 1/2 out of each of the 3 strands (so you only have 1/3 of each orginal strand now) and do 3 more full tucks. Trim nicely. For a bit of peace of mind maybe stitch up and down the splice a bit with sonme waxed twine or small polyester braid (0.5 or 1mm max). Doesn't have to be anything special pattern wise, it's just to help hold the splice togeather a bit when unloaded and new, it will settle nicely after a small amount of use.

Now you should have a nice soft entry into the gypsy for the rope and this should help minimise any slipping. Be aware it may slip or jump from time to time, sadly it's just the nature of the beast and far from winch specific, they all can do it.

Rope wise to use up there? Bit tricky to say from down here really. Marlow should be fine, to be honest the small amount of Liros I've seen/used I was far from impressed with and didn't like it at all. English braids should be worth a look, a good manufactuer. I know Samson (a US maker) has a presence in the UK and they could be worth a look as well. I say that as we use their Pro-Set on the Sth Pacifics here and it works a treat.

Give them a tinkle and ask what grade of nylon they use. If they answer Type 6-6, that is good.

And to save some bucks what about just extending your existing line rather than replacing the whole lot. Splice them togeather and taper out each end like the splice to the chain, should be fine. Or if you want to get real sexy do a nice long 'Long Splice', the one, if done nice, you can't see. Just a thought to keep the rum kitty from being beaten up too much

If I've missed something don't be afraid to ask, I'm more than willing to help fellow yachters.

I hope that helps. Safe and enjoyable sailing.
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Old 21-08-2008, 07:18   #9
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Thanks for all that, particularly about how to taper the rope/chain splice - you certainly know your stuff. I've been using the NZ-built winch for 2 years now and it does a good job. It occasionally struggles in a difficult wind & tide situation but a nudge from the engine to re-position the boat and get a fairer pull on the rode always fixes it. Mine is the only South Pacific I've seen in the UK and I don't know why they're not better known here as they seem good value for money.

You suggest splicing an extra length onto my existing rope to save the (in my case) beer kitty. The existing rope is 12mm. Only question remaining is: is this really strong enough for my bulky 28 footer (more Spray than Dragon) or would I be better upgrading the lot to 14mm. If 12mm would always be a worrisome weak link I'd rather replace it and go thirsty in preference to going adrift. Main reason for wanting to stay with 12mm was so more of it would fit in my smallish chain locker and let me anchor in deeper water e.g. in the Scottish sea-lochs where the shores fall sheer to considerable depths.

Thanks once again for all your help and advice.
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Old 21-08-2008, 22:00   #10
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After my experience with a long splice giving way while winching in the purse with 50 tonnes of tuna in the net, I am strongly prejudiced against them. I am sure you could use the 12mm elsewhere and have a continuous length.
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Old 22-08-2008, 17:21   #11
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Robert, a good long splice should be fine but I totally agree that if Jim did have a use for the existing rope a new full length is the better option.

Jim - The Sth Pacifics are actually made in Taiwan by a Aussie outfit. NZ's makers are Maxwell and James Nilsson. Strangely the Sth Pacifics are a bit under rated by most. They did have some issues in the early days (just like everyone elses did or still do). They are at the lighter end 'class for class' i.e. chain size for chain size. I think it's maybe just a case of people think the cheaper something is the worse it is. We see it often where people think the more they pay the better the product, which in many cases is true but not all.

Warp size? yes a 14mm would give you a lot more security from the chafe side alone. Strength wise the 12mm should be fine but (as I've noticed on one of my boats, which is similar to yours) when you have 40-45kts over the bow it suddenly seems to look about the size of garden twine. A couple of times I have been looking at it in a blow thinking hard to myself "at least 2500kg break, at least 2500kg break........." As yet it has not let me down. I race that boat a fair bit so stay small. If I cruised that more more I'd go to 14mm and 8mm chain.

The down side of 14mm is locker space as you mentioned and also the 'rope chain interface' (sexy word for splice ) will be bigger so increase the chances of the small dramas you are having there. Saying that we use 14mm to 8mm here and most work fine with the biggest problem being your i.e lack of locker space.
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Old 24-08-2008, 10:48   #12
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Thanks GMac & All for your advice, I've learned a lot. I'll go to 14mm rope and use as much as will fit in my chain locker whilst still allowing enough fall for the chain coming down from the windlass. For the odd time when that's not enough I'll have some more available to shackle on. Thanks again & good sailing.
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Old 25-08-2008, 00:56   #13
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Sounds like you have it sussed Jim. I hope it all works well for you.

Only to pleased to be of help. If you get stuck I'm here.... unless I'm there or having a rum, in which case the reply maybe about a 'hangover' late

I'd be interested to know how you get on with the rope hunting. If you have a moment let me know. I've been asked once or twice before and it maybe handy to add to the database for the next troubled owner.

Sail safe and anchor well,
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