Mark, I read the article attached but came to a slightly different conclusion regarding anchor and rode construction and deployment. (I also wonder what Mr. Smith's association is with Rocna anchors). I'll concur, any anchor rode or mooring rope can be stretched to its limits with enough force, be it from wind, waves, or current. While catenary of chain rode doesn't come close to equaling the tensile strength of the chain itself, it will lessen the effects of wave movements and other forces. Not everything about anchor rode is about keeping the anchor from dislodging from the sea bed. A boat that rides well at anchor generally doesn't have a jerking and lurching motion, which can be offset by. You guessed it. catenary in the anchor rode. I'll also put in a plug for using a snubber in areas where you'll likely get strong wind and waves that may put an anchor and rode to the test. But for all the reasons suggested by other posters, I'll continue to keep a length of chain between my stretchy 8 plait rope and CQR anchor. Not 100% chain, not 100% rope, a combination.
Chuck Gilchrest S/V Half Magic 1983 Landfall 35 Padanaram, MA From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Dr. Mark Bodnar via CnC-List Sent: Wednesday, August 17, 2016 1:01 PM To: cnc-list@cnc-list.com Cc: Dr. Mark Bodnar <drbod...@accesswave.ca> Subject: Re: Stus-List Windlass rebuff I can't offer up anywhere near the experience of others on this list - so I depend on learning from more experienced sailors. This group is part of that, plus I pay for a membership with Attainable Cruising Adventure - https://www.morganscloud.com/ - lots of great info that has been tried and tested in challenging climates (including an extensive discussion on jacklines and tethers) On the topic of catenary effects of chain - they argue that the effects are pretty minimal. This article is offered as evidence of the calculations. Chain still offers some benefits, just not so much in catenary effect. http://www.petersmith.net.nz/boat-anchors/catenary.php Mark There is no cure for birth and death save to enjoy the interval. - George Santana On 2016-08-17 11:18 AM, Chuck Gilchrest via CnC-List wrote: Chuck, Avoiding chain on anchor rode means you're giving up one of the most important aspects of the rode: the catenary effect of shock absorbsion. By allowing some of the chain to lie on the ocean (or lake) bottom, the effort that it takes to lift the chain off the bottom before the line goes taut, serves as a shock absorber to wave, wind, or current. Also, using chain on an anchor rode means you can get by with a somewhat shorter scope in a crowded anchorage without worrying that your anchor will break free. Using only rope between your clean and the anchor allows for very little catenary and as such, your cleat and the anchor rope is bearing the entire shock load of the boat all the time. If I had only rope on my anchor line, I would make sure I had a proper anchor rode snubber, rubber or otherwise, to manage those loads. On Half Magic, we use 25' of 5/16" Galv BBB chain spliced to 200' of 5/8" NovEight Novabraid 8 plait rope with a 25lb CQR anchor (which is probably a bit light for the size and weight of the boat). We rarely anchor in more than 20' of water where we sail although we might rethink that if we decide to cruise up in Maine or Nova Scotia. Chuck Gilchrest S/V Half Magic 1983 Landfall 35 Padanaram, MA _______________________________________________ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated! _______________________________________________ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
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