How much working load does my anchor chain need?

[UNCIVILIZED]

I can't imagine 1/4" (6mm) G4 chain being to small for a boat that size. Especially given that it's more than strong enough to fully lift the vessel with.
Personally, I'd be comfortable using that sized chain on something in the mid 30'/7 ton range.

As to the buoyant (rope) rodes thing, if interested, there's more discussion about techniques for them in a thread on Spectra anchor rodes. And yes, you read that correctly. Spectra as in Dyneema anchor rodes.

[Olddave]

Originally Posted by UNCIVILIZED

I can't imagine 1/4" (6mm) G4 chain being to small for a boat that size. Especially given that it's more than strong enough to fully lift the vessel with.
Personally, I'd be comfortable using that sized chain on something in the mid 30'/7 ton range.

As to the buoyant (rope) rodes thing, if interested, there's more discussion about techniques for them in a thread on Spectra anchor rodes. And yes, you read that correctly. Spectra as in Dyneema anchor rodes.

Hi Uncivilised,
I can't find any threads about Spectra Anchor ropes that have a positive conclusion. Would you mind providing a link.
I used spectra recently to tie the Cod end of a trawl net. It was good stuff and took some abuse but does not stretch. Stretch is a good thing with anchor rope. Chain has weight and a slow action to produce similar effect to stretch in rope.
Dave

[reed1v]

Originally Posted by Olddave

Hi Uncivilised,
I can't find any threads about Spectra Anchor ropes that have a positive conclusion. Would you mind providing a link.
I used spectra recently to tie the Cod end of a trawl net. It was good stuff and took some abuse but does not stretch. Stretch is a good thing with anchor rope. Chain has weight and a slow action to produce similar effect to stretch in rope.
Dave

You want as much stretch as possible, three strand nylon, snubbers, chain, and even a kettle to absorb shocks and keep the anchor from pulling out. Low stretch and braided lines not good.

[mako]

Originally Posted by reed1v

You want as much stretch as possible, three strand nylon, snubbers, chain, and even a kettle to absorb shocks and keep the anchor from pulling out. Low stretch and braided lines not good.

As a general rule you are correct. My previous point is that there are situations where a floating and/or neutral line is advantageous to be used. These lines may be low stretch and medium resistant to UV, but if they fit the situation then you accept and work within its limits.

[noelex 77]

The extra chafe resistance of Dyneema makes it attractive as a replacement for conventional materials in rope anchor rodes.

The expense is high compared to other ropes, and it floats, but the lack of stretch is one of the more difficult problems to solve. Attaching a nylon snubber, as we do for chain, it is not going to be easy at intermediate lengths.

The only practical way I can think of doing this, is to divide the Dyneema into reasonable lengths (say 10m). Put an eye splice in each end and use these loops to attach the snubber. Has anyone any better ideas? Dyneema does not hold knots well, so options are limited.

[conachair]

Originally Posted by noelex 77

Attaching a nylon snubber, as we do for chain, it is not going to be easy at intermediate lengths.

The only practical way I can think of doing this, is to divide the Dyneema into reasonable lengths (say 10m). Put an eye splice in each end and use these loops to attach the snubber. Has anyone any better ideas? Dyneema does not hold knots well, so options are limited.

If it's 12 strand you could make up an eye on a short length with some sort of spike (I've used a stub of a pencil to splice before) on the free end then just feed it into the centre of the main anchor rode, basically splicing an eye. Should be just a few moments to fit and milk back out again afterwards.

[noelex 77]

If I understand you correctly, I think that would work, but with reasonable thickness Dyneema, the inserted loops would need to be long to achieve an adequate bury. These would stick out of the main rode.

Individual lengths of Dyneema with a spliced loop on each end I think would be neater and the sections of Dyneema could be easily replaced if there was any chafe.

[reed1v]

Originally Posted by makobuilders

As a general rule you are correct. My previous point is that there are situations where a floating and/or neutral line is advantageous to be used. These lines may be low stretch and medium resistant to UV, but if they fit the situation then you accept and work within its limits.

Please tell, what are those situations?

[Snowpetrel]

Originally Posted by reed1v

Please tell, what are those situations?

Floating line is very handy in potentially high chafe environments like areas with coral or rocky bottoms. The floating line is less likely to chafe through because it is on the surface away from the rough bottom, unlike nylon which sinks and easily tangles around anything sitting on the bottom.

Ideally a float is also used to increase the bouyancy near the chain. Of course its not ideal in waters were other boats can run over the line, or in shifty wind conditions where you are likely to tangle the floating line in your rudder, keel or prop.

Nylons stretch can be a disadvantage in some conditions, where it can cause excessive yawing in gusts, rapid chafe and internal overheating. The dashews prefer polyester or dyneema for dock lines.

[UNCIVILIZED]

Originally Posted by Olddave

Hi Uncivilised,
I can't find any threads about Spectra Anchor ropes that have a positive conclusion. Would you mind providing a link.
I used spectra recently to tie the Cod end of a trawl net. It was good stuff and took some abuse but does not stretch. Stretch is a good thing with anchor rope. Chain has weight and a slow action to produce similar effect to stretch in rope.
Dave

Hi Dave, Here are some links. And there's more on this topic via the search. Including one on Beth & Evan's site entitled "The Right Rode". Which is a PDF of something the Dashew's did with Dyneema rodes. I can't get it or their site to work right at the moment though.

And the Dashew's have set up some Jordan Series Drogues using Spectra lines, due to the super high loads on such devices. Odds are you can find the info at SetSail.com Or perhaps via the JSD site.

Some of the other techniques are to be found in threads on Polyethelyne (sp?) anchor rodes. And to some degree, "the opposite", where fenders are used to buoy rope rodes up in coral country. With the supposed perk being that the fenders also act as kellets in reverse. But I'd have to see it to believe it.

http://www.cruisersforum.com/forums/...pe-167840.html
cruisersforums.com spectra anchor rode - Bing

And if you, or anyone else knows more on this, please post it


PS: Just found this Sea Anchor Testing with Steve Dashew and Zack Smith

[StuM]

This is a kettle:


This is a kellet:


Just sayin'

[mako]

Originally Posted by Snowpetrel

Floating line is very handy in potentially high chafe environments like areas with coral or rocky bottoms. The floating line is less likely to chafe through because it is on the surface away from the rough bottom, unlike nylon which sinks and easily tangles around anything sitting on the bottom.

Exactly. When I go diving here in the "potato field" which is just acres of limestone formations, I see nylon anchor lines all over the place (plus fishing lines of course). Following them is a great source of Danforths and Bruces! I use polyprop, but in crowded anchorages it is a disadvantage because it gets run over - luckily mostly by jet skis and jet boats.

Originally Posted by Snowpetrel

Ideally a float is also used to increase the bouyancy near the chain. Of course its not ideal in waters were other boats can run over the line, or in shifty wind conditions where you are likely to tangle the floating line in your rudder, keel or prop.

I wrap a bit of canvas or material around the chain/line splice. Polyprop does float like a cork. However, the polyprop/polyethylene mixes are only slightly buoyant, so they float underwater, not bobbing on the surface. I haven't tried them yet but I do plan to. I have not used Dyneema.

Lugger Line: http://www.google.com/url?sa=t&rct=j...KgIjifJ6xrfxAw

[sailabroad]

Im experimenting with threading dyneema through the chain to add some redundancy to the welded chain links we have( picture for reference our chain is on the bottom)

We don't have the full length yet but if it lasts might move to a smaller chain with the dyneema threaded the full length..it goes through the windlass fine and is incrediby strong, the chain protects the dyneema from coral.

[Don C L]

Originally Posted by gal ecker

Thank you all for the advice
I will go with the g4 1/4.
Now i just need to find where to buy it here in colombia or in panama

My boat and yours are pretty similar in weight and windage and I believe 1/4" G4 HT is the answer too. It's my choice, and I don't have a windlass too. 2800# swl is good for our boats. Let us know where you find the chain.

[Snowpetrel]

Originally Posted by sailabroad

Im experimenting with threading dyneema through the chain to add some redundancy to the welded chain links we have( picture for reference our chain is on the bottom)

We don't have the full length yet but if it lasts might move to a smaller chain with the dyneema threaded the full length..it goes through the windlass fine and is incrediby strong, the chain protects the dyneema from coral.

My concern with this would be the accelerated corrosion due to having wet salty rope up against the chain's galvanising in a damp anchor locker?

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