Comments on: Chain Size – Break Strength and Safe Working Load http://setsail.com/chain-size-break-strength-and-safe-working-load/ A New Paradigm for Cruising Sat, 11 Feb 2012 12:58:16 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Steve Dashew http://setsail.com/chain-size-break-strength-and-safe-working-load/comment-page-1/#comment-4979 Steve Dashew Thu, 04 Mar 2010 14:15:16 +0000 http://setsail.com/chain-size-break-strength-and-safe-working-load/#comment-4979 Hi Chris: Our goal is to have the highest holding power, most reliable anchor system, for the lightest weight. Once you have sufficient strength in the chain to connect boat to anchor, the best system for the weight will always be light rode/big anchor. Taking this to extreme, we'd be better with a Spectra rode (much lighter and stronger than steel) connected to an even bigger anchor. The net result would be higher holding for less weight, but there are chafe and self-stowing issues. The other problem with heavy chain and increased catenary is fouling on bottom debris and/or damaging the sea bottom, which is a byproduct of the heavier chain. Hi Chris:
Our goal is to have the highest holding power, most reliable anchor system, for the lightest weight. Once you have sufficient strength in the chain to connect boat to anchor, the best system for the weight will always be light rode/big anchor. Taking this to extreme, we’d be better with a Spectra rode (much lighter and stronger than steel) connected to an even bigger anchor. The net result would be higher holding for less weight, but there are chafe and self-stowing issues.
The other problem with heavy chain and increased catenary is fouling on bottom debris and/or damaging the sea bottom, which is a byproduct of the heavier chain.

]]> By: chris critchett http://setsail.com/chain-size-break-strength-and-safe-working-load/comment-page-1/#comment-4964 chris critchett Thu, 04 Mar 2010 05:48:41 +0000 http://setsail.com/chain-size-break-strength-and-safe-working-load/#comment-4964 Steve, Always an interesting discussion and tradeoff. What you're not mentioning is that the primary advantage to chain rodes, other than working nicely with windlasses and stowing themselves pretty well, is their weight. The more they sag into the catenary curve between boat and anchor, the more horizontal the pull at the anchor end, which increases holding power, and the more resistance there is to straightening the rode out, which has to happen before any real shock loading occurs. I point this out not to disagree with your choices, but simply to mention another variable that gets mixed into one of the more complicated decisions in outfitting the boat. For a given length of rode, you can certainly save a lot of weight in the bow (always a good thing, as you note) by downsizing the chain a bit, put some of that weight back into a larger anchor, and still come out ahead. OR, would you be better off, in terms of anchor holding, to use a shorter but heavier rode on a slightly lighter anchor? You say you frequently anchor on short scope with your heavy anchors; I suspect the same would be possible with a lighter hook and heavier rode. Given the options, I don't disagree with your selections at all, as I always opt for more rode length 'just in case,' but I was surprised you left this whole other can of worms out of the discussion. I'm sure it's at least some of the basis for the class societies' preferences. Sorry to muddy the discussion if I have. Please keep up the good work, love the site and your boats. I'm living vicariously here until I can either a) afford one or b) get to design something similar for someone who can. Best regards, Chris Critchett Steve,

Always an interesting discussion and tradeoff. What you’re not mentioning is that the primary advantage to chain rodes, other than working nicely with windlasses and stowing themselves pretty well, is their weight. The more they sag into the catenary curve between boat and anchor, the more horizontal the pull at the anchor end, which increases holding power, and the more resistance there is to straightening the rode out, which has to happen before any real shock loading occurs.

I point this out not to disagree with your choices, but simply to mention another variable that gets mixed into one of the more complicated decisions in outfitting the boat.

For a given length of rode, you can certainly save a lot of weight in the bow (always a good thing, as you note) by downsizing the chain a bit, put some of that weight back into a larger anchor, and still come out ahead. OR, would you be better off, in terms of anchor holding, to use a shorter but heavier rode on a slightly lighter anchor? You say you frequently anchor on short scope with your heavy anchors; I suspect the same would be possible with a lighter hook and heavier rode.

Given the options, I don’t disagree with your selections at all, as I always opt for more rode length ‘just in case,’ but I was surprised you left this whole other can of worms out of the discussion. I’m sure it’s at least some of the basis for the class societies’ preferences.

Sorry to muddy the discussion if I have. Please keep up the good work, love the site and your boats. I’m living vicariously here until I can either a) afford one or b) get to design something similar for someone who can.

Best regards,
Chris Critchett

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