Mixed anchor rode

Neeves

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I don't normally look at sailing blogs but I have become involved in this one

Into the wind | La vie au fil de l'eau et du vent

Have I posted this previously....?

Its a couple sailing round the world in a tiny, if sub 8m is small, performance yacht - its valuable in that - never think your yacht is too small. They are currently in Tasmania replenishing funds - stranded by Covid.

Its relevant as their rode was mixed, 8mm chain (far to big in my view) and textile. They have no windlass. The rode has seen better days and they are buying 60m of (my) HT chain to replace the mixed rode (and will use, I think its 8mm, Kermantle dynamic climbing rope as a snubber). They are having an extra 10m of 6mm HT for a second rode. Their Spade S60 they had welded up (plate shank to fluke) in Tahiti as it wobbled and when their chain is galvanised they will have the anchor regalvanised at the same time. In the meantime they have bought a new Excel. As I've mentioned before I have no financial involvement - they order and pay direct and I just act as an unpaid facilitator and QC manager (I just have my ego stroked :) ). I think they will order the chain and galvanised coating during the w/c 4th October. I had not been aware that the S60 has a plate shank. We have a S80 with one of the fabricated shanks.

Take care, stay safe

Jonathan
 

Birdseye

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I don't see anything antisocial about using a mixed rode - though I understand your comment. When we enter a crowded anchorage you can see those using a rope rode (its 'different in 'view' from chain) and we make allowances - even if nothing else they were there first and have 'rights'. But an answer is smaller chain, maybe high tensile (I understand Jimmy Green sells 6mm HT, but says there is no demand (I asked them). Though not necessarily HT as many seem to carry chain much stronger (and heavier) than needed if chosen for strength - but offset using smaller chain with a snubber.

Snubbers are just another form of a mixed rode in a different 'arrangement'.

Jonathan

Tensile strenght and abrasion resistance arent the same thing. That said what normally condemns a chain is rust from loss of galv which is itself nothing to do with tensile or abrasion of the steel itself.

Yes a mixed rode is antisocial here in the UK. Oz is just a bit bigger :)with fewer people and presumably larger anchorages where ranging about at anchor isnt such an issue.

Snubbers are not the same thing at all. Inevitably they absorb movement in a much smaller distance and so with a higher shock load. A decent length of 10mm nylon and you dont feel shock at all. Like being on a giant bungy cord

In the end we all find a set up we are happy with. I went from a mixed rode with lots of nyslon back to chain, the reason being a combination of excellent weather forecasts and natural timidity which meant that I only ever anchored where shelter was excellent but crowded and the forecast was good The rode was rarely anything other than straight up / down

P.S. Just read your post and comment on the French couple and chain size. The strength of a chain rode is almost always far greater than the holding power of the anchor or the strength of the cleat - an 8mm chain has a breaking strain of maybe 6 tonnes weight. Do you think that the cleat on a 30ft modern GRP boat would withstand that? Instead the merit of chain size is the weight of the catenary and abrasion resistance
 
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Dutch01527

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It also depends where in the uk you sail. In the Bristol Channel there are 10m plus tidal ranges and a pretty unforgiving coastline with few points of refuge. Ability to anchor in 20m in an emergency is essential.

If I was to carry all chain the weight would be to heavy for my 28 foot boat and too heavy to wind in via my manual windlass. A mixed chain / polysteel rode seems like the only viable option. My polysteel threads through the windlass and into the chain locker with no issue. Admittedly I have only done so in moderate conditions and have not tried to retrieve it in heavy conditions
 

Wing Mark

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When I did a lot more yacht sailing 25 to 40 years ago in the UK and Channel, virtually none of the sailing yachts I went on had a windlass and all had mixed rodes.
The boats were a mix of cruisers up to Contessa 32 size and racing boats up to 40ft .
I did get a few rides on bigger racing boats, I don't recall seeing an anchor let alone a windlass. I'm sure they each had two anchors stowed below along with the RORC minimum chain.
Reading a few books, maybe more chain was carried in the 60s?
I guess before synthetic rope became common chain was a better choice than natural fibres?
 

Neeves

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Tensile strenght and abrasion resistance arent the same thing. That said what normally condemns a chain is rust from loss of galv which is itself nothing to do with tensile or abrasion of the steel itself.

Yes a mixed rode is antisocial here in the UK. Oz is just a bit bigger :)with fewer people and presumably larger anchorages where ranging about at anchor isnt such an issue.

Snubbers are not the same thing at all. Inevitably they absorb movement in a much smaller distance and so with a higher shock load. A decent length of 10mm nylon and you dont feel shock at all. Like being on a giant bungy cord

In the end we all find a set up we are happy with. I went from a mixed rode with lots of nyslon back to chain, the reason being a combination of excellent weather forecasts and natural timidity which meant that I only ever anchored where shelter was excellent but crowded and the forecast was good The rode was rarely anything other than straight up / down

P.S. Just read your post and comment on the French couple and chain size. The strength of a chain rode is almost always far greater than the holding power of the anchor or the strength of the cleat - an 8mm chain has a breaking strain of maybe 6 tonnes weight. Do you think that the cleat on a 30ft modern GRP boat would withstand that? Instead the merit of chain size is the weight of the catenary and abrasion resistance

A minor comment

The WLL of 8mm G30 chain is 750kg and Proof Load is 1,500kg - at and beyond Proof Load the chain will stretch permanently. the specification strength is 3t (commonly nearer 4t). The holding capacity of a 15kg reasonable anchor (Rocna/Spade/Excel and possibly Epsilon) in good holding (with no chop nor veering - so as tested) is 2,000kg. Its a decent match. The anchor usually drags due to poor holding, chop, veering or operator error, chains seldom stretch (and now almost never fail) and cleats or windlass pulling out of the deck is not something commonly mentioned - I'd say the specifiers of chain, anchors and scantlings seem to have it all 'about right'.

The weak link is the owner or crew. If you reach tension where something might break the crew will be 'unhappy'.

Abrasion resistance is limited to the galvanising thickness which is consistently around 70 microns - chain weight has nothing to do with it (I've tested it) the gal thickness is the same, 6mm or 12mm - 6mm has less abrasion, it spends less time being swept over the seabed in light winds and less time actually on the seabed when the wind increases.......


But your thesis is correct that we all use what we are comfortable with - I try to offer options that some might not have heard of - which might offer them more comfort than they thought was possible.

The French couple are unusual - sailing round the world in, what looks like, a very twitchy, performance inshore racer. If you want to really test a relationship they set an example. All credit to them. They are living the dream in a yacht most would never consider for a weekend, let alone sail half way round the world. Weight to them is important, I understand (we raced a 10m yacht in RORC Blue Water classics). I have yet to see their yacht, promised for early next year (when we install the new rode), so I don't know its build. But the 6mm will have the same strength as the 8mm it replaces, at or near 4t.

Here they are, beached for a bit of a hull wipe

Resizer_16316691991820.jpeg

A modern take on a bilge Keeler

Resizer_16316682173575.jpeg

Fair winds,

Take care, stay safe

Jonathan (making the most of a finite tenure)
 

Mountaineer

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We have 50m of 8mm chain on a vertical electric windlass. I was thinking of splicing an additional 30m of 14mm 3 core for use in those places/conditions where we might need a longer anchor rode. In view of a previous comment I shall now conduct a test before I do this in order to check whether the warp will pass down into the anchor locker without jamming. with jamming. Our boat 9.4m and pretty heavy displacement.
 

doug748

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We have 50m of 8mm chain on a vertical electric windlass. I was thinking of splicing an additional 30m of 14mm 3 core for use in those places/conditions where we might need a longer anchor rode. In view of a previous comment I shall now conduct a test before I do this in order to check whether the warp will pass down into the anchor locker without jamming. with jamming. Our boat 9.4m and pretty heavy displacement.


You might get it down the standard yacht chain pipe but I think you have no chance of pulling it out without snags. Seldom used rope, soaked in seawater, will remain damp, promote rust on the chain, can smell, bring weed in with it and become generally unpleasant.

It might be better to splice a steel thimble into your long line, and keep it is a cockpit locker where it can be ready for other uses and won't be festering away. It only takes moments to shackle on. I have a similar length of chain and have only used my rope on the anchor twice in decades, both times in the Bay of St Malo. I have used it far more often when multiple rafting.

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