Correct Cordage for Attaching Bitter End of Chain

[Dockhead]

I am bringing new anchor chain on board today and need to decide on cordage for attaching the bitter end to the boat.


From the original build, there was a fairly thin (maybe 12mm) piece of nylon or polyester three-strand for this purpose.


I think the basic idea is:


1. It needs to be thin enough that the windlass won't engage it (so it won't be powered out forcefully and broken off by the windlass); and


2. It needs to be long enough so that it does come out through the windlass (otherwise the chain will be powered out by the windlass, breaking the rope).


3. You need to be able to cut it in an emergency (I keep a knife hanging in the chain locker).


I don't have any thin three-strand lying around, but I do have some double braid.


But maybe single braid dyneema would be better? I could splice it on at both ends, rather than knotting it, and it will be way stronger. I don't think strength is so critical here, and in any case the eye bolt it's attached to is not all that strong, but dyneema will be slipperier so less risk of getting caught in the windlass, and less easily broken. On the downside, somewhat harder to cut.


And I will paint the last 3 or 4 meters of the chain signal orange.



I have accidentally powered my chain out all the way once or twice in the last 13 years with this boat, and missed losing the ground tackle just by this thin piece of cordage, so I think it's really important to do this right.


Any tips?

[jtsailjt]

I used Dyneema so it can be thin enough to not bind in the hawse pipe but still have adequate strength. As you mentioned, it needs to be long enough to reach up through the hawse pipe and around the windlass. I fastened mine to the chain about 3’ from the end so the chain will still be engaged with the windlass when I first see the dyneema as I’m letting out chain, giving me the option of simply reversing the windlass if desired. But your method of painting the last few feet of chain would work as well.

[Dockhead]

Thanks!

I think I will use dyneema.

When single handed I often winch from the helm, and I don't have a chain counter. I've never let all the chain out this way, but there is some risk

[Q Xopa]

Another potential advantage of using Dyneema is it floats. So if you have to release your Anchor rode in a hurry, providing it's long enough for the depth you are in. Maybe quicker than using a fender.

[Breaking Waves]

a vote here against dyneema for this application. . . . if there is a risk of the chain 'free-running out' (eg like when clutch is accidentally released. There can be a big shock load if that happens, which dyneema would make worse (because no elasticity) and nylon would help cushion.**

If your chain simply can not free run out ever (no clutch and no chance ever of shaft key dropping out) then tis is ofc not an issue to be concerned with.

Also why put in a material that is harder to cut, when ability to cut is a safety feature. With a sharp knife you can certaintly cut dyneema, but you may have to saw a little on it (depending on the load when you are cutting). With nylon it would go more easily.

Pretty much any rope fiber can do this job adequately, so I would not overthink it. But I would suggest that dyneema fits the application less well than something with more elasticity.

** Note: in a shock loading application, Dyneema can in fact often break before similar-sized nylon, despite the nylon have much less static strength, because of the difference in shock loading caused by the large difference in elasticity.

[StuM]

Originally Posted by Breaking Waves

Also why put in a material that is harder to cut, when ability to cut is a safety feature. With a sharp knife you can certaintly cut dyneema, but you may have to saw a little on it (depending on the load when you are cutting). With nylon it would go more easily.

Pretty much any rope fiber can do this job adequately, so I would not overthink it. But I would suggest that dyneema fits the application less well than something with more elasticity.

** Note: in a shock loading application, Dyneema can in fact often break before similar-sized nylon, despite the nylon have much less static strength, because of the difference in shock loading caused by the large difference in elasticity.

A conbination could give you the best of both worlds.

A loop in the bitter end of the dyneema with a shorter multiple loop lashing of smaller nylon or other cordage to the eye bolt. With your knife in the chain locker, you just have to cut one strand of the lashing rather than sawing through the dyneema.

[rslifkin]

If you can see it in your application, as an extra safety to avoid unintentionally pulling on the attached bitter end, I marked my rode with a series of black stripes starting 15 or 20 feet from the end. Basically a "stop windlass now" warning.

[Breaking Waves]

Originally Posted by StuM

A conbination could give you the best of both worlds.

Yes, agreed, I actually thought about mentioning a mixed solution, but decided not to under the cover of 'let's not overthink this'.

[pcmm]

I would avoid dyneema in this application for 2 reasons. If it small enough to slip past the gypsy then its going to be a shock load when it comes to a stop at the end of its length. But mostly If you've ever tried to cut dyneema you now its not something that you can do in a hurry! takes a seriously sharp knife and time to saw through it! get some 3 strand nylon 3/8" strong enough to hold the chain to the boat but easy enough to cut in a hurry!

[Dockhead]

Originally Posted by rslifkin

If you can see it in your application, as an extra safety to avoid unintentionally pulling on the attached bitter end, I marked my rode with a series of black stripes starting 15 or 20 feet from the end. Basically a "stop windlass now" warning.

Yeah, I did something like that. Last 10 meters painted signal orange.

[Dockhead]

Originally Posted by Breaking Waves

a vote here against dyneema for this application. . . . if there is a risk of the chain 'free-running out' (eg like when clutch is accidentally released. There can be a big shock load if that happens, which dyneema would make worse (because no elasticity) and nylon would help cushion.**

If your chain simply can not free run out ever (no clutch and no chance ever of shaft key dropping out) then tis is ofc not an issue to be concerned with.

Also why put in a material that is harder to cut, when ability to cut is a safety feature. With a sharp knife you can certaintly cut dyneema, but you may have to saw a little on it (depending on the load when you are cutting). With nylon it would go more easily.

Pretty much any rope fiber can do this job adequately, so I would not overthink it. But I would suggest that dyneema fits the application less well than something with more elasticity.

** Note: in a shock loading application, Dyneema can in fact often break before similar-sized nylon, despite the nylon have much less static strength, because of the difference in shock loading caused by the large difference in elasticity.

Yeah, that's pretty persuasive


I guess I will use a piece of old sheet then.

[The Way]

Originally Posted by Dockhead

I am bringing new anchor chain on board today and need to decide on cordage for attaching the bitter end to the boat.

Any tips?

In the shallow waters of the US east coast, I use 30 feet of poly line that floats. That way if I have to cut the line I might be able to find the anchor and chain again.

By the way, why would you want to go below to cut the line? I recommend keeping a knife in your pocket so you can cut the line from the foredeck.

Fair winds,
Jack

[Scorpius]

Originally Posted by Dockhead

Yeah, that's pretty persuasive


I guess I will use a piece of old sheet then.

Old sheets are usually polyester which doesn't have much elasticity either. I would stick to nylon.

[RaymondR]

I use about 16mm nylon with a "quick link" shackles on a spliced eye. This arrangement passes through the winch and allows me to unshackle the chain.

[bnork]

If you're going to tie the line off, two loops and two half hitches would be preferred over a bowline, as a bowline can't be released when under a load, but the half hitches can.