Anchor line Querie

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Again I humbly approach the "Greybeards of Dorydom" in an effort to improve my seamanship.
I have started this new thread rather than change Dick's original post relating to the applicable Bruce size for his boat.
While offering my thoughts on the subject in his thread I included a description of our rode and mentioned that we went with the double braid based on advice received from my commercial buddies. Their thoughts were "you will use (handle) and store this stuff daily, don't compromise the fine attributes the braid affords just to gain the stretch." So far this seems to be decent thinking and with no windlass in the immediate future even more so.
In Bob Austins post which followed mine he mentioned using "both" line types with the 3 strand serving the purpose of a snubber.
My own thoughts were that plenty of chain and proper scope would answer the need. Then I read some of the experienced opinions and listen to the high wind stories while at anchor and I have to wonder about including the snubber. At this point I have no anchor horror stories but this looks like something to get proactive about and not gain any of this experience. After all "Experience is what you get when you don't get what you want"
OK Guys, pump me full I'm all ears. Mike on Huda Thunkit
 
Mike-

Great topic!

constructions_threestrandrope.jpg
b_7.jpg


Three strand (left) and double braid rope construction (right) for clarification. The three strand with it's double twisted construction has more give or elasticity than the double braid, which has more of the fibers in a more linear configuration. Some double braids designed for low stretch have the core fibers lying totally straight, unbraided. Also, nylon fibers are much more elastic than polyester. Some of the new fibers like kevelar and spectra are many times stronger and have less strech than either nylon or polyester and are useful on sailboats in control lines where minimum stretch is desirable, and are also used in braided fishing lines for maximum strength and minimum diameter.

The main reason folks usually stick with 3-strand besides the elasticity/shock absortiing factor is that the gypsies on windlasses that accept both the chain and rope on one gypsy require 3-strand on this combination gypsy.

s_VR2500_3500_large.jpg


If you use doublebraid with chain, you have to have a windlass with both a chain gypsy and a rope drum, and manually change the rode from the drum to the gypsy when you reach the transition from rope to chain.

s_VMC_500H_150.jpg


This defeats one purpose of the windlass, which is to be able to raise anchor without going onto the foredeck, both for convenience, and for safety in heavy weather.

Also, in this configuration with gypsy and drum, you're back to feeding the rode down into the locker by hand. at least usually.

HOWEVER !!! I have seen some more unconventional windlass designs that will work with double braid and feed it into the locker below. I doubt if they will pass the chain part of the rode, however.

I have used a rode which consists of 100 feet of 1/4" chain followed by 200 feet of 1/2" three strand rope, which effectively is all chain under some shallow anchoring situations. The weight of the chain has a quieting effect on the wandering ("searching") of the boat in windshifts, while the weight of the chain acts much like an elastic link as the boat has to lift the chain off the bottom as it is pushed backward by the wind. This works for moderate conditions, but in really heavy weather, the chain goes straight and the boat is jerked to a stop as the chain goes taunt with virtually no give. At that point, you have to let out some rope to cushion the shock.

Joe.
 
I've felt some good stretch on 1/2" line - usually when in a raft-up and
being a primary anchor boat. I'm not a fan of anchors out on every
boat since it turns into a circus if the raftup needs to breakup.

Did the stretch help prevent the anchor from breaking loose? Dunno.
Maybe. But, if I was using a windlass, I wouldn't worry about it and
just use triple twist anyhow. And if I wasn't using a windlass, I'd use
a soft-lay triple twist because it isn't that hard on the hands. However,
even though a 22' doesn't really need 1/2" line, I'd use that because thinner
line is hard on the hands. So, I'm sure 1/2" triple twist on a 3,500lb boat
doesn't stretch that much...probably wouldn't change to a line that
stretches even less.

Mike
 
By the way, while I'm thinking about it, I figure that the reason that double braid rope is usually not used on windlasses is that the windlass gypsy's teeth contact only the cover part of the double braid, and the inner core is free to slide around a little inside the cover.

As you run double braid through the windlass, the differential between where the core is in relation to where it's supposed to be gets greater with the amount of rope pulled in, creating tension between the cover, which has been pulled in more, and the core, which has been pulled in less. This would create internal tension in the rope, which would not lay well in the locker or elsewhere. We notice problems when this occurs in ropes used in sailboats.


This problem would not be as noticeable with a drum/gypsy combination windlass, like I showed in my first post, because the rope is wound around the drum two or three times, and the differential doesn't build up between the cover and the core continually as it would with in the teeth in the gypsy.

At least that's my theory!

Joe.
 
Good morning Joe, and thanks for the considerable information you have provided regarding all aspects of the braided line and it's relationship to use with a windless.
Before you wear your finger tips out pecking out all this info, I should point out that I don't have and probably never will have a windless. :oops:
This is not to dissuade your efforts but rather to save you some of that considerable effort you have already expended on my behalf.
I would however be interested in this snubber thing if you can shed some light on that, rigging options etc.
I guess I could have been more complete it my original post but the unmentioned consideration when deciding on line type was the whether to or not to incorporate a windless. With out it in the picture the only other consideration was this stretch thing which I chose to ignore. However I may be able to have the best of both worlds by incorporating the stretchy thingy if I can get its use figured out.
Oh yea, feel free to post, post, post on any of my threads, not only is your information considered valuable but we all know the other reason it's OK. :wink Mike on Huda Thunkit
 
Mike, I don't want to convince you to get a windlass, but thought I'd relate my experience with my 25. 15th boat, first ever with a windlass, I have no strength problems (...yet) and usually have a couple of able-bodied teenagers with me on most trips. It was a safety issue. Being so light up front and having a full cabin with its side windage causes the bow to 'hunt' in higher winds and seas at anchor. I found it very difficult to make steady progress pulling up the anchor and rode with wind and a 2-3 foot chop -- trying to move to a better location, the wind shifted. I was at the helm easing the boat forward, two teenagers on the bow, they had to constantly re-cleat the rode when the bow swung to one side or the other. A lot of tension on the rode, pitching seas, that was the last time we did it manually. Love my windlass, easy, quick, wonderful -- and safe!
 
Mike-

As I remember, I also was a little unsure of what Dr. Bob meant when he was describing the means of adding some three-strand to the double braid via some hitches in order to gain some elasticity. I don't think it was because he was unclear, but because I didn't understand some of the terms he used up front, and didn't take the time to look them up!

Also, don't worry about my time typing or thinking. Keeps the old brain from dozing off into the disuse syndrome of old age!

Joe.
 
OK, I got it together and looked up the rolling hitch and thought it through!

ROLLING HITCH

You leave your regular anchor line intact, and use 30 ft sections of three-strand tied to it with rolling hitches at their ends, making sure the three-strand is a little shorter than the double braid that it is paralleling. This allows the three strand to take on the load, provide some stretch, and at the same time the double braid is your main rode or anchor line.

Joe.
 
I haven't followed up on the other thread. The idea of a snubber is two fold--one as a shock absorber --usually used with all chain rodes. At at certain point all chain is bar tight and there is no cantry to give shock absorpition. I dove on all chain rode in 80 knots of wind--and can assure you that there

Anchoring is an art, as well as a science. We like to "feel" the anchor set--either by feeling the rope, or even putting a foot on the chain as it comes up and the anchor digs in.

My snubbers are normally lighter line than the main anchor rode--for example for a 62 foot 60,000 lb boat we had one snubber of 1/2" 3 strand nylon and the second of 5/8" 3 strand nylon. For a 22 Foot C Dory 3/8" would be more than enough--and 5/16" would be fine for many applications. As noted using thin line is hard on the hands--and thus people use 7/16" or 1/2" line where 3/8" or even 5/16" might be plenty strong (depending on the conditions)
 
These last couple post are hitting the nail on the head guys, I can see some elements of a clove hitch in the rolling hitch with some non slip adders. I am surprised to hear the part about smaller diameter line used for the snubber but it makes sense from a stretch stand point. I sure hope to not endure some of the extreme anchorage situations mentioned by earlier posters. But want to include this tool in order to have the bases covered if ever needed. Anchoring in Prince William Sound I have many well protected options and will always opt for one of these rather than an open scenario.
Thanks for the help with this, as always once the right guys get involved the results are favorable.
Mike on Huda Thunkit
 
I thought of one other example last night: Two of us were anchored in a Cove in Santa Cruz Island--some of you may know that occasinally heavy rollers come into these coves unexplained suddenly. This occured. I had the snubbers on, my friend with a very similar boat had no snubber. We both had the same size and type of anchor chain (all chain rode) to our great suprise--my friend's chain broke when these sudden heavy waves hit--it was the shock loading of the chain which broke it. Even three strand might have prevented this. I know of at least one 40 foot boat which rode out the Cabo Storm of 1982 (about 28 well prepared cruising boats lost on the beach at Cabo San Lucas)--on a 5/8" double braid nylon rode--it was almost chafed all of the way thru--but the inner core was intact enough to prevent breaking.

Yes, the lines are very light--but as you noted this is for the shock absorbing ability--The reason that I have two, is at some point the smaller is at its elastic limit--and the larger line starts to take the load. Of course the lengths must be balanced to allow this to occur properly.

The variation of a taught line hitch or rolling hitch is very similar to clove hitch--but has an extra turn which jams down on the line under load, and allows it to untied easily.

One final point about double braid and drum winches. All of the racing sailboats use a smooth braid line (various materials--and construction techniques)--the drum winches have 3 turns, there is no slipping of inner and outer cores--and most winches have self tailing tops, which are very similar in constrction to the combination rope chain gypsy on the windlass used on the C Dory models. I have not tried double braid on these windlasses--but it may well work "OK"-- as for slipping--inner and outer--probably not a major issue. The crippers of the windlass compress the line and I suspect that any slippage would be small.

Regards,
 
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