Newbie anchor to chain to rope connection question

[teccs]

I have a 20' power catamaran (https://tinyurl.com/y7ssbejx)
I have no anchor windlass.
My anchor is a galvanized danforth that has a 1/2" slot in the top for the chain connection.
My understanding is that I want to stick with all galvanized steel to prevent problems with dissimilar metals.


I need to set up an anchor for coastal cruising with the notion of anchoring out rather than paying for marinas.


I see 1/4" chain (https://tinyurl.com/ybzkhld7) and 3/8" rope (https://tinyurl.com/ycf2nyly).


But what I can't figure out is how to connect them all together with something that has the same strength as the rope or chain.


The shackles and connecting links that I am finding (5/16" for 1/4" chain) all have much less working load limit. I would appreciate any suggestions on this.


Also, do I need a swivel?


Lastly, if any of my above specified parts are not appropriate for my intended use, I am open to suggestions.

[Pete7]

You are right to be wary of links particularly cheap stainless types from chandlers.

This is worth a read:

Connectors – Cox Engineering

In the end I went for a stainless one and just accepted the different metals. Personally I am not in favour of a swivel, its another item that can fail.

Pete

[GordMay]

Greetings and welcome aboard the CF, teccs.

[Suijin]

Not all shackles are created equal. You want a Crosby shackle. You can find them on Amazon. The Crosby G209A 2.0T would be s good choice.

For the rope to chain connection you can splice the rope directly to the chain. Three strand splicing is extremely simple. A YT how-to video will have you doing it in 20 minutes.

[Ken Z]

use crosby or titan , you mat have to double them up to fit your anchor, I would not redrill your anchor for the shackel. do not use china made or ss.

[Briney Bug]

The shackles that are generally available, if they have embossed letters and numbers, are sized to fit and equal in WLL that of G3 chain. For G4 chain, high-strength (alloy) shackles, if they have embossed letters and numbers, are designed to fit and equal in WLL that of the chain. If the letters and numbers are imprinted in the shackle, the WLL will be as stamped, but the dimension will probably be bigger than that of a shackle made to an recognized standard.
The two most common splices for attaching rope to chain is a 2-strand rope-to-chain splice, and a 3-strand rope-to-chain splice. Both can be found in "The Ashley Book of Knots", but Brion Toss' book, The Rigger's Apprentice" does a great job of explaining not only how to tie them, but why.
Most of the times a swivel is necessary only when:
1. You'll be anchored for extended periods where the wind or current reverses direction.
2. Your anchor spins on deployment or recovery.
3. Your anchor needs to be rotated to fit into the anchor roller and a partial twist imparted in the rode to rotate the anchor is not practical.
4. Multiple anchors are deployed and their rodes attach at a common point, a swivel can be installed between this common point and the pendant that leads to the boat.
For a gypsy, the rope spliced to the chain usually is twice the size of the chain. This can also work if the rode doesn't go through a gypsy. However, sizing rope like this, if you use the ABYC's standard that the rope's tensile strength should be 8x the load on the ground tackle, reveals that the rope will not come close to the chain's WLL. This is why we recommend for storm level, even gale force winds, a second rode is available, sizing the rope for the conditions, then matching the chain to the rope.

[hamburking]

Your anchor line should have a spliced on steel thimble at one end. A shackle connects the thimble to the chain. Another shackle connects the chain to the anchor. Use a quality anchor shackle. Don't buy any of this stuff from a hardware or big box store.

Unless you live in a weed free, beachy/clay area, your danforth is not suitable. If you have the $$$ get a rocna. Otherwise, a used bruce anchor would suffice. I don't know the weight or specs of your power cat, but at 20 feet would guess a 7.5kg bruce would work, and a 5kg bruce as a lunch hook. If you live in a weedy area, you might consider a "pointy" anchor. There are whole other threads on anchors, so I don't want to drift off topic here.

[thinwater]

I think what the OP is missing is that 5/16" shackles fit 1/4" chain.

He has a 20' boat; he does not need grade 4 shackles from Crosby, only good grade marine shackles. With a rope rode he will NEVER see a working load over 500 pounds. Ever. There is no requirement to match the strength of the chain; he will use 1/4" mostly because good quality 3/16" galvinized chain is rare. However, it is all the load actually calls for. (ABYC table 1 does not even go down to 20 feet).

I would splice the 3-strand right to the chain; no shackle, no thimble. Simple.

No swivel. Specific to 3-strand for larger boat, you NEVER use a swivel with rope; it will unlay under high load and it will rotate. No swivel. Chain is different because it is non-rotational.

[tstano]

Originally Posted by thinwater

I think what the OP is missing is that 5/16" shackles fit 1/4" chain.

He has a 20' boat; he does not need grade 4 shackles from Crosby, only good grade marine shackles. With a rope rode he will NEVER see a working load over 500 pounds. Ever. There is no requirement to match the strength of the chain; he will use 1/4" mostly because good quality 3/16" galvinized chain is rare. However, it is all the load actually calls for. (ABYC table 1 does not even go down to 20 feet).

I would splice the 3-strand right to the chain; no shackle, no thimble. Simple.

No swivel. Specific to 3-strand for larger boat, you NEVER use a swivel with rope; it will unlay under high load and it will rotate. No swivel. Chain is different because it is non-rotational.

The voice of reason, have fun sailing.

[Souzag818]

Originally Posted by Ken Z

use crosby or titan , you mat have to double them up to fit your anchor, I would not redrill your anchor for the shackel. do not use china made or ss.

[SuW]

The Ashley Book of Knots, while fascinating, is not anything I'd recommend to a beginner at ropework.

I like this site for its clarity:
https://www.animatedknots.com/chainsplice/

[teccs]

Thank you to all for the helpful answers. I purchased this shackle: https://tinyurl.com/yaft93qf


I own Ashley's book of knots and will learn to do the splice using YT as well. Thanks for the tip.



I read the article about connectors by Cox Engineering. Very informative. Thanks for that.


I will keep an eye out for a good deal on a better anchor.


I won't use a swivel.


Cheers!

[HopCar]

I’m guessing you will be hauling the anchor by hand. On a twenty foot boat I’d use about 15 feet of 1/4” G3 Proof Coil Chain and 1/2” three strand nylon. The 1/2” line is stronger than you need but it’s easier on your hands.

I wouldn’t splice the line directly to the chain. The rope tends to wear where it goes through the chain link. I only splice directly to the chain when I’m using a windlass that handles both the rope and chain.

I would splice a thimble in the rope end and join it to the chain with a good forged 1/4” shackle. Uses similar shackle to join the chain to the anchor.

I used stainless chain, shackle and thimble on my boat. The anchor was galvanized and I had no problem in more than twenty five years. I don’t recommend stainless chain only because it just costs so damn much.

[thinwater]

Why the common preference for splicing an eye with a shackle?



The advantage of a direct splice are:

• One less shackle
• Smoother over the roller
• Easier on the hands
• Simpler splice (no critical fit to thimble)
• Thimble cannot shift and do damage

Strength is the same. Neither chafes (because the direct splice does not move against the chain).

[Mike Banks]

Power cats are heavy--and I think your anchor could be improved. A Danforth is OK in mud or sand. I would go for a 30 pounds minimum Manson Supreme or something of similar modern design.

Have you considered setting a permanent mooring? You will need to apply for one and pay an annual fee for it and maintain it, but it will be cheaper than a marina berth and more reliable than an anchor.

To get back to the rope to chain connection, I think you need an all-chain rode if you are going to leave your vessel unattended. Having said that, I use what looks like a crown knot as a rope to chain splice, if using a windlass. You are not--so you can use a thimble spliced into the rope, and connect it to the chain using a galvanised shackle, with the pin thread sealed with nail polish or paint, and the pin moused to the shackle with galvanised tie-wire.

I use a locked bifurcated eye-splice with nylon rope and a thimble. A normal eye splice could pull loose in an extreme situation, but in any case, use as many turns as is practical. Six at least for nylon.