Rope for various lines

Moderator: GreenLake

Re: Rope for various lines

Postby GreenLake » Tue Mar 24, 2015 12:57 pm

As I mentioned, I recently re-did my traveler,and in the process, I experimented again with the height. It helped that I had experienced crew for a few weekends in a row, but she was new to the boat, so didn't take anything for granted. We started off with it too high, and noticed that we were "chock-a-block" (is that the same as "two blocked" ?) before we had maximally sheeted in. Lowered it in steps and we are now at the same height mentioned in Phill's guide. That leaves a little gap between the blocks.

K.C. I got lost among all your blocks, can you post a picture? Same for your Cunningham.
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Re: Rope for various lines

Postby K.C. Walker » Tue Mar 24, 2015 3:39 pm

Well, I guess my jib Cunningham is really a jib halyard tensioner, similar to that pictured in the rigging guide by Phill Root.

As to my blockhead confusion, this is how I want to rig it but at present the block on the boom has a Beckett which is were the end is tied. 100
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Re: Rope for various lines

Postby GreenLake » Tue Mar 24, 2015 4:07 pm

And what is wrong with a becket. I've never had anything else and it's worked fine. Come to think of it, what I don't have a is a swivel, on that block at the end of the boom, so the main won't twist. I do have a swivel on the block on the traveler. Not having a swivel on the other one means the main can get rigged the wrong way, so it needs a bit of attention at that stage.
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Re: Rope for various lines

Postby talbot » Wed Apr 08, 2015 1:07 am

Nice to have a complete catalog of line decisions for a particular boat. Whether you agree with all the specifics or not, it's really useful.
I didn't quite follow the section on Prusik knots and the jib sheets. Maybe I need to see it.
One note about the butterfly knot: I used to use this in rock climbing for certain types of fixed-rope anchors. It's nice in that the attachment loop comes out at right angles to the working ends. But I found that after loading, at least on conventional nylon and polyester kernmantel rope, it is essentially a permanent loop. The knot jams so tightly it might as well be spliced. In the present context (mainsheet bridle) that probably doesn't matter. But I suggest experimenting with an overhand or figure 8 (which can eventually be undone and adjusted), then tying your final version with the butterfly.
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Re: Rope for various lines

Postby GreenLake » Thu Apr 09, 2015 12:11 am

Talbot, thanks for the kudos. I don't claim my choices do more than make sense for the way I use my boat. And I arrived at some odd choices by "accident", but I think it's useful to show that, too. There's often no single "right" choice.

The rope I use for the bridle (now) is very reluctant to hold knots (it's rather stiff when you try to bend it tighthly). On my first iteration of the bridle with a standard double braid, I had a simple overhand knot (not a loop) through which I inserted the removable U shackle from the block. After years of service, that got so tight that I could not even remove the shackle, because the ends widen just slightly.

In my setup, as long as the loop doesn't pull tight, I'm fine. (As long as I can remove the block, the knot can stay in the line, I don't need to remove it to get the line off the boat for storage). In effect, I am able adjust for slight errors in placement of the knot by the way I tie the two free ends together. For that I use a modified sheet bend which has always been easy to work open again.
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Re: Rope for various lines

Postby Interim » Thu May 21, 2015 12:00 pm

Can I introduce anchor rodes? I am using a single-braided poly right now, the only advantage of which is that it floats. It is impossible to coil, so a quick anchor drop is almost impossible.

What do other people use? I have a 10lb mushroom, which doesn't need much strength. I don't even have a chain at the end; just tied on with a fisherman's bend.

--john
1979 DSII
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Re: Rope for various lines

Postby talbot » Thu May 21, 2015 12:50 pm

Anchor lines are usually nylon, because they are expected to absorb shock, and nylon is the best material for that. Twisted nylon is the stretchiest. I have used cheap hardware-store 3/8" nylon, with a very soft lay. I recently upgraded to New England twisted nylon, which has a harder lay, similar to what they used to make for mountaineering. I think it well be less likely to snag and tangle than the hardware-store stuff, but haven't used it much yet. Disadvantages of nylon are that (1) unlike polyester, it degrades in sunlight, so it needs to be stored below deck when not in use; (2) unlike polypropylene, it absorbs some water, so it's heavy and slow to dry when wet. (So storing it below deck results in a damp and moldy cabin.) I usually leave it out just long enough to dry in the cockpit, then put it back in the cabin as soon as I can.
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Re: Rope for various lines

Postby willyhays » Thu May 21, 2015 1:41 pm

I use Yale Cordage 8-strand plaited nylon. This rope is very strong, easy to handle, and, because of its plaited braid, stows in a much smaller space than 3-strand or double braid.
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Re: Rope for various lines

Postby TIM WEBB » Thu May 21, 2015 2:46 pm

Been meaning to post these shots of the jib soft shackle I'm currently using. It's 1000 lb Spectra, threaded through the center of the sheet, and double fingertrapped through itself to keep it in place. Works great!

2073

2074
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Re: Rope for various lines

Postby GreenLake » Thu May 21, 2015 4:24 pm

TIM WEBB wrote:Been meaning to post these shots of the jib soft shackle I'm currently using. It's 1000 lb Spectra, threaded through the center of the sheet, and double fingertrapped through itself to keep it in place.


That's another way to do it. Thanks for posting the pictures.

BTW, what you call a "double fingertrap" is commonly known as a Brummel splice (or sometimes locked Brummel), for those wanting to look up instructions. The name appears to be traceable to the name of an illustrator for a book by Brion Toss (Working Rope Book 5 - Basic Braided Splices by Brion Toss).

Given the moderate loads on a DS (compared to larger boats), the sheet you show is overdimensioned (sized for handling rather than minimally required strength, I expect, and nothing wrong with that). As a result there should be plenty of reserve strength and no concerns for the perhaps somewhat unorthodox method of running the shackle through the sheet. Given the strength of Dyneema, the shackle itself should be plenty strong despite the narrow diameter. However, depending on UV exposure or chafing you may need to check and replace it after so many seasons. Keep us up-to-date on that.

(I haven't seen Dyneema age to the point of where it failed, but some of mine is no longer colored but looks bleached. So getting an idea whether that represents incipient failure, or just fading of the colorant, would be useful. Your UV exposure should be more.)
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Re: Rope for various lines

Postby K.C. Walker » Thu May 21, 2015 4:55 pm

I use a similar jib sheet set up. Though, mine is just a single 1/8 Amsteel about 10 inches long. I agree, it does work great. In higher wind situations when the jib is flapping, the jib sheets stay relatively calm in comparison to tied directly to the sail (therefore less fouling). Though my season is much shorter, I am on season four and no sign of deterioration. On my UPS I use an 18 inch long one with the theory being lighter weight sheets for very light wind days. It works particularly well in that application in that there is no bump to snag on the forestay as I drag the sheets around for tacking.
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Re: Rope for various lines

Postby talbot » Thu May 21, 2015 5:18 pm

KC, don't you also use a continuous sheet?
Are the ends tied together? If so, do they meet at the short pennant to the jib clew, or do they meet in the cockpit?
Or are they spliced, in which case, is the sheet removable from the boat without unstepping the mast?
Has anyone tapered their sheets to have a thick grippable (5/16" or 3/8") line aft of the turning blocks and a thin space-age fiber forward of the blocks? If so, what measurements, materials, and splices did you use?
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Re: Rope for various lines

Postby TIM WEBB » Thu May 21, 2015 9:49 pm

GreenLake wrote:That's another way to do it. Thanks for posting the pictures.

BTW, what you call a "double fingertrap" is commonly known as a Brummel splice (or sometimes locked Brummel), for those wanting to look up instructions. The name appears to be traceable to the name of an illustrator for a book by Brion Toss (Working Rope Book 5 - Basic Braided Splices by Brion Toss).

Given the moderate loads on a DS (compared to larger boats), the sheet you show is overdimensioned (sized for handling rather than minimally required strength, I expect, and nothing wrong with that). As a result there should be plenty of reserve strength and no concerns for the perhaps somewhat unorthodox method of running the shackle through the sheet. Given the strength of Dyneema, the shackle itself should be plenty strong despite the narrow diameter. However, depending on UV exposure or chafing you may need to check and replace it after so many seasons. Keep us up-to-date on that.

(I haven't seen Dyneema age to the point of where it failed, but some of mine is no longer colored but looks bleached. So getting an idea whether that represents incipient failure, or just fading of the colorant, would be useful. Your UV exposure should be more.)

I'm just used to using the terminology we use in the parachute industry, and fingertrap pretty much means anytime a line is drawn through and/or into itself or another line in order to form a "lock". Comes from the ancient Chinese woven toy into which you stick your fingers and can't pull them out. Pre-dates Toss/Brummel by several millennia I believe ... ;-P

My jib sheet is simply what D&R supplies as the correct size, and I like it that way. 3/8" I think? As a (mostly) singlehander, I need something I can easily work with one hand, oftentimes at odd angles, and it seems to set and pop out of the cam cleats very easily. I took great care to use a very smooth fid and not break any fibers of the sheet when pulling the shackle through. Unorthodox? Hardly: we make such connections all the time on parachute gear, and that takes a lot more stress than a jib sheet.

As far as wear and tear goes, it's really easy to tell on Spectra when it's starting to go: it will start to have little "barbs" sticking out of it, which are broken fibers. Happens on parachute steering lines where they go through the guide rings on the risers. The jib shackle does not encounter such abrasion under normal use. I've been using this shackle for about 2 years now, and there is no sign of any wear at all. And unlike nylon, it's pretty much unaffected by UV exposure.
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Re: Rope for various lines

Postby GreenLake » Thu May 21, 2015 10:20 pm

Tim, you've given an good example that what may be unorthodox in sailing contexts may be SOP somewhere else. Glad to learn. Thanks for the tip to look out for the barbs as a wear indicator.
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Re: Rope for various lines

Postby TIM WEBB » Fri May 22, 2015 9:20 am

Yeah, terminology is a funny thing: the same word can mean two different things in two different contexts, and two different words can mean the same thing too! ;-P

I have no experience (yet) with Amsteel - is it also made from Spectra fibers?
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