The 2000 kg holding myth

[NormanS]

Of course, but if "snatch loads" occur, for whatever reason, I would have thought that being prepared to mitigate "snatch loads" would be a good idea. I see anchoring location, riding sails, heavier chain, dual anchors, bridles et cetera as just tools to be used when required.

You seam to be a person who applies your own thoughts and ideas based on your own experience. Yet when Neaves offers his advise, based on his own experience, you are fairly dismissive of it.

I assume that most folks who read anchoring threads on this forum can make their own minds up and take what they want from the anchoring advise offered.

No, I don't dismiss Neeves's advice. What I do repeatedly do is to point out that his methods are not the only methods. His boat was a comparatively light catamaran, and I'm sure that his preferred methods worked well for him, and for his type of boat.
Boats are different, and what works for one, may not be the best or be needed, for others. I do not tell other people what they should or shouldn't do.

 

[Bouba]

In the lifting industry all the components are defined by strength, G80, G100 and G120. Components are also defined by size, metric chains are 6mm, 8mm, 10mm, 12mm - maybe larger. All 8mm components are made to the same size specification and it is impossible to use 6mm or 10mm components with 8mm components - they simply will not fit. All components are embossed with their size (6mm), strength 100 (aka 10) and are sometimes colour coded. You can tell at a glance if a 6mm G80 unit is part of an assembly of G120 units. This is unlike our components where anchor shanks are different thicknesses and different sized chain can fit the same shackles.

If you down size your chain, as we did, from G30 8mm to a galvanised G80 you still are subject to the same, or similar, rode tensions (so you use the same anchor and need the same shackle (because a smaller shackle would be insufficiently strong). That same shackle is now too big for 6mm chain. Historically you might have had a large chain link added to your rode - but this introduced other issues - and the answer is to use an Omega link.

This is a 15kg steel anchor shackle hole with a G80 3/8th" shackle (fits neatly, bow through the hole) joined to high tensile 6mm chain, the 6mm chain is stronger than the 8mm it replaces. The device to join the 6mm chain to the shackle is a 6mm omega link.

The clevis pin of the omega would accept a bigger chain link, say 8mm, but the jaw of the link is too small to accept the bigger link. The clevis is a tight fit, they tend to need to be hammered in, and they are secured with hammer in pins (you can see the 2 hammer in pin ends). The use of the Omega is 'single use' as they are difficult to disassemble.

View attachment 183550
This our chain after much use (Ive replaced the hammer in pins with cotter pins, I swap and change frequently as I test items and ideas.
View attachment 183553


Omega links come in different forms and some are called pear links, that one top row, second from left. Alternatives to Omega links are hammerlocks, the pale blue, large bright yellow and the green device. The top row, apart from the shackle, are all 6mm devices, pins are the same diameter, the jaw of the slot is less than 8mm. Omegas tend to be neat(er), and hammerlocks smoother - than shackles (that's a 3/8th" shackle). The darker blue Omega is 6mm, but it is an old design the version on the left is much neater.

View attachment 183552

Here I have played about with my Boomerang to accept Omegas, or Hammerlocks. The original Boomerang design was designed round 3/8th" shackles but it was a bit clumsy needing a shackle at each end of the boomerang and one on the anchor - all ready to catch on a bow roller. I even designed a Boomerang to attach directly to the chain - but it was a devil to assemble - so its in the pending bucket, awaiting more inspiration. These Boomerangs are made with Duplex stainless, a G60 steel except the top one is a G80, Bisplate 80 (the same strength as many anchor shanks).
View attachment 183554

Other differences

The strongest shackles are G80, the strongest chains in current use are G120.

Bow, "anchor' shackles are commonly sold galvanised, most lifting kit is painted or power coated - its part of marketing - I strip the coating off (paint stripper) and I have mine galvanised. But they last quite well, are not particularly expensive and you can chop them off and replace with a new unit.

The lifting industry is quite innovative - if you look at their lifting hooks, which we might use to secure a snubber to the chain rode, their designs make ours look like something out of The Ark.

If this is all too brief, I'm conscious NormanS has a short attention span , I can elaborate.

Jonathan

Thank you Jonathan, that is an impressive answer

 

[zoidberg]

I assume that most folks who read anchoring threads on this forum can make their own minds up and take what they want from the anchoring advise offered.

 

[Bouba]

Can’t be an anchor discussion....that many people couldn’t agree with each other

 

[Neeves]

Now and then, yachts break free from moorings in gales.
Never heard that it's the cleat that fails.
One mooring contractor I chatted to was estimating that the broken worn chains he'd seen were good for a few tons, based on his experience of having broken one or two pulling sinkers out of the floor.

I've heard stories of anchor chain deforming to the point where it goes stiff, and or breaking, so I think it's possible for a medium sized yacht to exert more than a ton or two, in storm conditions.

The modern fashion for a short skinny bit of second hand nylon as a snubber seems likely to put a big shock load on things when the snubber breaks and then the chain goes tight with a bang.

Sorry Norman, another long post - but you have no need to read it. Reading posts, as far as I know, is entirely voluntary. Equally people can ignore the suggestions - its a free world - no-one is imposing on choice.

Anchors are a compromise - and so are snubbers.

If your snubber does not offer, depends on the size of the yacht - but say 35', around 1m of stretch under the most arduous of conditions - then it lacks elasticity. You can 'produce' that 1m of stretch by having a thin or very long snubber. Nylon stretches to a maximum of about 40% and then fails. 10m of snubber will thus stretch to 40% (4m) and then working on a 4:1 safety factor - 1m is 'about' right. But nylon ages, don't we all, and with age lacks elasticity (don't we all ). For that 35' yacht - 10m of 10/12mm nylon seems to work. You can extend the life of the snubber by using more than 10m but going thinner - you will reduce life. Going thicker the snubber will also last longer but loose that ability to stretch.

10m of snubber might seem excessive - for that 35' yacht - run the snubber from the aft cleats, or sheet winch, to the bow and you have already used 6m - 10m (depends on where the sheet winch or transom cleat is located and which you use) and then you only have 4m of nylon extending from the bow to your chain attachment. '4m of snubber' extending from the bow is easily manageable.

If you have a 20m length of, retired, climbing rope use the sheet winch and if the wind gets up you can simply deploy a few more metres of rope - it will extend the life of your snubber. You obviously need to deploy a few more metres of chain, or if you have planned ahead - the excess chain needed is simply in the 'lazy loop'.

It is inevitable - your snubber will fail or if you are recycling climbing rope you could retire your snubber and use another free piece.

Accepting that your snubber will fail means you should (must) have a simple fall back (and a spare) - and when the snubber fails the snatch load is taken by that fall back - which can be a short length of nylon attached to a strong point. Just bear in mind - if you endure snatch loads on your yacht then those same snatch loads are being managed by your anchor - better to have a decent snubber (with fall back and spare) or a long and heavy chain rode and lots of catenary.

A long and heavy chain rode (no long snubber, just a short one to protect the windlass) or a well matched snubber achieve exactly the same result. They 'manage' snatch loads and chop - which you choose, the long chain rode or the snubber - is up to you.


None of this is rocket science, none of this is difficult, none of this is original. Starzinger on Hawk (google him) did all of this decades ago. He was a rock climber and sailed to high latitudes (Labrador) and used, his retired, climbing rope as both snubbers and shore lines. I don't know if he secured his snubber at the bow or at the transom Dashew (google him as well) was the great proponent of the thin HT chain (I think he may have persuaded Peerless to make the original galvanised G70 chain specifically for the anchor rode). If Dashew and Starzinger did it - then its good enough for me.

For owners of multi hulls. The supplied bridle is too short and too beefy. It offers no or almost no snubbing. Change it!

Confession time. On Josepheline, 38' x 7t cat, windage of a 45' AWB we recycled climbing rope from gyms. We also downsized the chain from 8mm to 6mm. I found a local gym with high walls and they had 30m lengths - they were happy to offload some to me. (I understand its difficult to source lengths in the UK - gyms need to chop the retired ropes up - you need to persuade your local gym you are not going to use the ropes for height safety). Gym ropes are 12mm diameter. Once we had decided that we wanted to be able to use the full 30m, we effectively used only 15m for each snubber (a bridle) we bought 2 x 30m lengths of 12mm, we wanted the ability to extend and end for end. We found new 12mm rope was not quite as elastic as the recycled ropes we had sourced and downsized to new 10mm climbing rope (2 x 10mm x 30m). This worked perfectly. We have ended up with almost new 2 x 30m x 12mm climbing ropes . One day someone with a bigger cat, or a bigger yacht will ask about snubbers - and they will be the beneficiary of our 'suck it and see'

Climbing rope is almost the ideal. Its specifically made to be elastic, it has an abrasion resistant outer cover - if you are lucky - it comes free allowing you to experiment. Its a bit of a devil to knot. When we bought new we specially asked for eyes to be sewn in one end of each rope and asked for the sewn portion to be 20cm long. A sailmaker could sew eyes (or you can knot - but its a bit clumsy).

Snubbers are like the suspension in your car - they make the ride more comfortable. I have always considered the analogy apt and as with a car, that has a whole host of comfort inducing devices, your snubber does not ONLY need to be nylon (you still use the catenary in your chain), adding some of those dog bone rubber things work well for chop - think outside the box!

Jonathan

 

[thinwater]

Can’t be an anchor discussion....that many people couldn’t agree with each other

Obviously, they are all wrong about different aspects of anchoring, and all wrong about this specific aspect in different ways.

I would have thought that was obvious.