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Old 05-08-2015, 09:39   #16
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Re: Best Source for New Pretty Rope/Line

Quote:
Originally Posted by Dockhead View Post
Clearly some racer vs cruiser culture clash going on here

I hear what you're saying, but are you sure it's really applicable here?

If your high tech jib sheets have a 10:1 saftey margin --

and a simple 10mm double braid furling line has a 25:1 safety margin --

Would you be wrong to be using the double braid furling line? What's the risk?

Just because Dyneema is stronger, does it mean you really need a 50:1 safety margin? Especially when you're happy with only 10:1 with your sheets?

Doesn't seem rational to me. Don't forget the mechanical advantage of the furler drum.

I admit though that the stripped dyneema line on that furler looks awfully pretty And "pretty" was part of the OP's brief.
Dockhead, we're going probably more than a little OT here, with this, but... if you could explain your numbers & math to me, I'd surely appreciate it. As I don't understand their real world basis. Including the part about furlers & mechanical advantage, plus your safety factors numbers.

On that last point, I just went & measured a Harken MK III, Unit 2.5, and
- The foil diameter is about 1.5" at it's widest point (it's an airfoil section).
- The furler drum, bare, is about 3.5' in diameter.
So, doing the math on those, for rough mechanical advantage, I get 2.333 :1 favoring the furling line vs. the sail's sheet (not counting for the bit more, advantage wise, due to the foil shape).

So, yeah, some error on my part, when it comes to mechanical advantage, & the needed, real world, furling line strength. But even if one were to "remove" a bit of that mechanical advantage factor, it'd still be nice to have one's roller furling control line be, say 1/2 the strength of the sail's sheet. Thus, giving you a 2:1 safety factor. Probably a fair number given that the hardest working sections of RF control lines live in the zone where salt spray, & green water immersion are pretty constant companions. That, & said lines never really get any relief from UV exposure either.

Is there something else which I'm not seeing in terms of mechanical advantage here, in terms of furlers? I suppose we could query Harken, or Profurl, but...
Call or email a professional (rigger), & fill me in if I'm wrong. Otherwise, I'm thinking that the loads on the control line for RF ain't small.


As to me being in love with high tech lines, for the most part, especially in apps where the loads are moderate to high, I can't see how they don't make sense.
The price of a piece of Dyneema cored double braid, with a breaking strength akin to 16mm Dacron with a bowline tied in it is Real close to that of the size of Dacron in question. And the Dyneema cored lines have proven to have about the best lifespans of any of the double braids out there, regardless of material.

I could post up the tech specs, & prices on the various lines in question, but they wont say much that I haven't already stated, assuming memory serves.

Oh, & BTW, New England Ropes "Regatta Braid" is probably my Fav when it comes to apps where stretch isn't really a factor. Like in a 6:1 purchase in the mainsheet of a 30'-35'er. It's got a great hand, as it were.
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Old 05-08-2015, 09:49   #17
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Re: Best Source for New Pretty Rope/Line

Quote:
Originally Posted by Dockhead View Post
Clearly some racer vs cruiser culture clash going on here

I hear what you're saying, but are you sure it's really applicable here?

If your high tech jib sheets have a 10:1 saftey margin --

and a simple 10mm double braid furling line has a 25:1 safety margin --

Would you be wrong to be using the double braid furling line? What's the risk?

Just because Dyneema is stronger, does it mean you really need a 50:1 safety margin? Especially when you're happy with only 10:1 with your sheets?

Doesn't seem rational to me. Don't forget the mechanical advantage of the furler drum.

I admit though that the stripped dyneema line on that furler looks awfully pretty And "pretty" was part of the OP's brief.
I'm not arguing that the dyneema core is required for its strength alone, I just think such ropes make for a far superior furling line overall...

I've really come to like Samson's MLX, I use for my headsail sheets and furling lines... It has a beautiful hand, no tendency whatsoever towards hockling, runs very nicely through blocks, holds well in rope clutches, and so on... And it's difficult for me to picture its cover ever "rotting" as Kenomac's staysail furling line did recently, although one must suppose that sort of failure could likely be alleviated by actually inspecting the line once in a blue moon, or so... ;-)

For me, the primary advantage gained is from minimizing the diameter of the line that will run through all the lead blocks of your system, and wrap on the drum... Even more important for those using a closed drum furler, I'd say... As one who sails a boat of the size that I always furl my headsails by hand, the advantage of using a furling line of the largest diameter possible makes a big difference, to me... In hindsight, if I were to do mine over, I'd definitely go up in size from 3/8 to 7/16, as my Profurl drum would still easily accommodate the larger core... And the overall reduction in friction gained by going with a line as smooth and 'slippery' as a dyneema core is noticeable even on a boat as small as mine...
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Old 05-08-2015, 10:06   #18
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Re: Best Source for New Pretty Rope/Line

Quote:
Originally Posted by UNCIVILIZED View Post
BTW, for that much impending splicing, it'd pay off BIG to get familiar with the following tools.

Get a couple of Home Depot type shop/work knives with the retractable blades. Specifically, the type which have the blades where you can snap off a section of it when it gets dull. As well as set how much blade that you have protruding from the handle... for assisting in controlling the depth of cut in certain splicing situations.

Said knife impressed Brion Toss & Co. when I took it with me to one of their splicing classes, ages ago. Which was nice praise.
One suggestion for anyone working with dyneema rope, which can be a bit tough to cut...

An ordinary kitchen knife with a ceramic blade goes thru that stuff like butter, and makes a very clean cut... I keep a couple of ones I picked up at Harbor Freight for a few bucks for that purpose, and keep one stowed in the cockpit, another at the mast, in the event I ever have to cut through dyneema in a jiffy...

Not sure what it is about ceramic, but they are awesome for working with Amsteel, or similar...

There's a cool ceramic rigger's knife out there now, even Brion is sold (and is selling) them:

Brion Toss Yacht Riggers, Sailboat Rigging::Rigging Tools


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Old 05-08-2015, 10:39   #19
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Re: Best Source for New Pretty Rope/Line

Quote:
Originally Posted by UNCIVILIZED View Post
Dockhead, we're going probably more than a little OT here, with this, but... if you could explain your numbers & math to me, I'd surely appreciate it. As I don't understand their real world basis. Including the part about furlers & mechanical advantage, plus your safety factors numbers.

On that last point, I just went & measured a Harken MK III, Unit 2.5, and
- The foil diameter is about 1.5" at it's widest point (it's an airfoil section).
- The furler drum, bare, is about 3.5' in diameter.
So, doing the math on those, for rough mechanical advantage, I get 2.333 :1 favoring the furling line vs. the sail's sheet (not counting for the bit more, advantage wise, due to the foil shape).

So, yeah, some error on my part, when it comes to mechanical advantage, & the needed, real world, furling line strength. But even if one were to "remove" a bit of that mechanical advantage factor, it'd still be nice to have one's roller furling control line be, say 1/2 the strength of the sail's sheet. Thus, giving you a 2:1 safety factor. Probably a fair number given that the hardest working sections of RF control lines live in the zone where salt spray, & green water immersion are pretty constant companions. That, & said lines never really get any relief from UV exposure either.

Is there something else which I'm not seeing in terms of mechanical advantage here, in terms of furlers? I suppose we could query Harken, or Profurl, but...
Call or email a professional (rigger), & fill me in if I'm wrong. Otherwise, I'm thinking that the loads on the control line for RF ain't small.


As to me being in love with high tech lines, for the most part, especially in apps where the loads are moderate to high, I can't see how they don't make sense.
The price of a piece of Dyneema cored double braid, with a breaking strength akin to 16mm Dacron with a bowline tied in it is Real close to that of the size of Dacron in question. And the Dyneema cored lines have proven to have about the best lifespans of any of the double braids out there, regardless of material.

I could post up the tech specs, & prices on the various lines in question, but they wont say much that I haven't already stated, assuming memory serves.

Oh, & BTW, New England Ropes "Regatta Braid" is probably my Fav when it comes to apps where stretch isn't really a factor. Like in a 6:1 purchase in the mainsheet of a 30'-35'er. It's got a great hand, as it were.
Concerning mechanical advantage:

1.5" versus 3.5" is not a 2.333:1 advantage.

It's 0.75" squared over 1.75" squared or a 5.44:1 advantage -- very serious difference. Remember that it's not the proportion between diameter, but circumference, which determines the mechanical advantage.

You can work out yourself, the difference between stretch and breaking strength between 10mm double braid (breaking strength 3690kg or so) x 5.44, compared to whatever high tech line you want compare it to, also the relative stretch characteristics, compared to the maximum sail loads, for your particular application. If you use 14mm racing dyneema (like Marlowe D2 Racing 78) for sheets, for example, you get breaking load of 9300kg, more than double the 10mm polyester. But considering the 5.44x mechanical advantage, the 10mm polyester still has greater reserve of strength (like almost triple) than your high tech sheets.

I think the numbers show 10mm ordinary polyester furling line would be more than adequate for my boat.


Concerning Regatta Braid -- thanks for the tip. I don't know if I can find it here, but I'll try.
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Old 05-08-2015, 11:37   #20
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Re: Best Source for New Pretty Rope/Line

Lots of interesting, and good, info going into the thread. Back to chatting with the mfr: while a couple of the previously mentioned shops are great to work with getting your online purchase of lines -- do take the time to have a chat with New England Rope and/or Samson Rope depending on your application and concerns if you end up liking one of their rope lines.

I take a look at what's available and then chat with the mfr about the specific application if I have a concern or just want to make sure it's right for my application.

Our rigging needs are different than yours, as the aesthetic of our boat is a pre-WWII classic schooner. The majority of our lines are simply 1/2" New England Rope 3 strand polyester. Even so, we do have some new hi-tech lines in use. Our running bobstay as well as breastlines/guardwires are 3/8" dyneema (Amsteel Blue), our running backstays are 3/8" Amsteel Blue where there used to be 3/8" wire and 13mm Endura Braid Classic (dyneema with a cover that looks like a traditional braid) on the lower sections that we handle.

I love the creamy color and classic look of dyneema cored Endura Braid Classic and it would both work great and look great on your boat. The same series Endura Braid comes in a variety of colors as well.

We've also used a "looks-traditional-but-is-high-tech-while cheap" Samson arborist 3-strand called promaster that is polyester with polyolefin core. Wouldn't be right for your era/style of boat, but I bring it up because for anyone with traditionally styled boats, it's great stuff, low stretch and low cost. We use 5/8" Promaster for two of our four halyards as well as jib sheets. It does have a green fleck in it rather than straight on white. The folks at Samson state they make runs of it for the tall ships from time to time but one has to order 5K ft or so to get them to make a run. So a rigger might do so, not an individual boat owner.

Best of luck in getting your running rigging all as you'd like it to be!

Brenda

PS--I do all our rigging and splices. The Brion Toss tool is good for beginners, the loop that does end up needing replacing can be replaced with dyneema fishing line. Once you're a more experienced splicer, you may find (as I have found) that an ordinary set of fids works quickly without the limitation of the Toss tool - you can only pull the Toss tool, it is not made for pushing. The Toss book "Riggers Apprentice" is very good for traditional 3 strand rope information. Not so much for newer lines where the mfr's own online instructions for splicing are superior.
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Old 05-08-2015, 15:03   #21
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Re: Best Source for New Pretty Rope/Line

Quote:
Originally Posted by Dockhead View Post
Concerning mechanical advantage:

1.5" versus 3.5" is not a 2.333:1 advantage.

It's 0.75" squared over 1.75" squared or a 5.44:1 advantage -- very serious difference. Remember that it's not the proportion between diameter, but circumference, which determines the mechanical advantage.

You can work out yourself, the difference between stretch and breaking strength between 10mm double braid (breaking strength 3690kg or so) x 5.44, compared to whatever high tech line you want compare it to, also the relative stretch characteristics, compared to the maximum sail loads, for your particular application. If you use 14mm racing dyneema (like Marlowe D2 Racing 78) for sheets, for example, you get breaking load of 9300kg, more than double the 10mm polyester. But considering the 5.44x mechanical advantage, the 10mm polyester still has greater reserve of strength (like almost triple) than your high tech sheets.

I think the numbers show 10mm ordinary polyester furling line would be more than adequate for my boat.


Concerning Regatta Braid -- thanks for the tip. I don't know if I can find it here, but I'll try.

Well, thankfully you found the error in my math. My little voice was nagging at me that something in there was awry, but as I said at the time, finding it then was beyond me.
Being an insomniac of late snared me it would seem. My apoligies.

Funny that you should mention the Marlow D2, as from what I've seen of it, it's nice stuff. And the colors it sports that I've seen it in, are pleasantly vibrant.
On the Regatta Braid, I think that New England has changed their "recipe" for it, if memory serves anyway. So don't go purchasing it sight unseen, in quantity before trying it out.

Thinking on those two ropes (D2 & Regatta Braid), & the fact that Dockhead & I, respectively, are both on continents where they're rare. D2 being a European item, & Regatta Braid being a US one. If one is looking for cordage (and other things), it still helps to pick up a slew of periodicals now & again, as at a minimum, you'll run into magazines from other lands, with new & different advertisers. Which will give you new ideas on available gear, as well as points of contact & manufacturerers to query for their selections of wares.
Even the differences between two countries right next to one another, that speak the same language can be astounding.
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