Dynamic Climbing Ropes Used on Boats ?

[jonesie]

Hi

I heard someone mention recently something about using dynamic (stretchy) climbing ropes for climbing masts. their reasoning was that is is "safer", i dont see how that would be as you wouldnt be falling on it. also how the hell would you get it to the top of the mast in the first place, unless you replaced one of the halyards with a stretchy rope which makes no sense...to me anyway.

Any thoughts??

[David M]

It is better to have a second safety line so the fall cannot happen in the first place. You don't want to trust you life to one thing working if you can avoid it.

[Astro]

Rookie sailor, long time climber here: the only thing "safer" is that in a fall, the stretch absorbs some of the shock. However, it makes the length of that fall less predictable. I can see no good reason for it on a sailboat where the movement should be about getting there and tieing off. Once in position, tie off with a back-up, (lobster claws or short line). Recreational climbing includes regular falls as a matter of course, but in the relatively low elevation, high clutter of rigging work I say keep a short, static (no-stretch) line, get the job done, and stay out of harm's way. P.S. You're fired half-way down.

[Cheechako]

I used my sailing harness. Looped it around the mast once above the speaders. then firmly attached where i'm working.

[estarzinger]

Originally Posted by jonesie

Hi

I heard someone mention recently something about using dynamic (stretchy) climbing ropes for climbing masts. their reasoning was that is is "safer", i dont see how that would be as you wouldnt be falling on it. also how the hell would you get it to the top of the mast in the first place, unless you replaced one of the halyards with a stretchy rope which makes no sense...to me anyway.

Any thoughts??

I actually use dynamic climbing line for my anchor snubber and for my traveller control line (to absorb gybe shock loading), but agree with you that low stretch static line makes more sense for mast climbing.

[thinwater]

They sometimes carry a separtate static line for accending, when on big-wall aid routes. A static rope is for catching falls; climbing one with mechanical aids is like climbing a rubber band. It's very energy inefficient, and it's worse for climbers, since the rubber band is 150 feet long.

Some sailors hoist a separate rope, using the halyard, and climb on that to save wear on the halyard. This can make great sense on high-tech halyards, which can be too slick to climb safely; mechanical accenders are designed for polyester rope. Many riggers do this to protect the customers' rigging.


History lesson: Old climbers often refer to climbing a rope with mechanical accenders as "jumaring", since the dominant model for many years was "Jumar." Needless to say, I have a pair!

[nautical62]

Cavers and others who simply ascend a rope, usually prefer a static line such as a caving rope. For ascending a mast, I see little value in using a dynamic climbing rope, other than you may feel it has less wear or abbrassions and it may also fit ascenders better. Whether you ascend the rope or get hauled up by someone else with a winch, you simply will not experience the fall factor that is generated during a lead climber fall.

Personally, when I get hauled up, my concern is not at all that the rope will fail, or that sitting back on it will place any kind of impact on me. I'm more conerned about the pulley and fittings at the top or human error.

Also, I prefer to tie in with bowline or figure 8 follow through to reling on a shackle.

I also agree with David M, that backing up the entire system with another halyard (or other rope) is probably one of the better safety precuations you can take.

(I have ready access to retired gym ropes - I use them for dock lines, my anchor snubber and my dinghy painter, but not for mast climbing.)

[Jim Cate]

Originally Posted by estarzinger

I actually use dynamic climbing line for my anchor snubber and for my traveller control line (to absorb gybe shock loading), .

G'Day Evans,

Well, once again you have come up with a novel and interesting idea. I'm quite curious about the snubber application. What size line do you use (and, since I'm ignorant about climbing rope, what variety) and what operational advantages do you find compared to the usual 3-strand or braided nylon?

Another fascinating application!

Cheers,

Jim

[delmarrey]

Originally Posted by David M

It is better to have a second safety line so the fall cannot happen in the first place. You don't want to trust you life to one thing working if you can avoid it.

Ditto!

I hoist up a climbing rope on the second jib halyard as a safety, and for repelling back down. Marine grade rope doesn't like being twisted around a descender so tightly.

[estarzinger]

Originally Posted by Jim Cate

Well, once again you have come up with a novel and interesting idea. I'm quite curious about the snubber application. What size line do you use (and, since I'm ignorant about climbing rope, what variety) and what operational advantages do you find compared to the usual 3-strand or braided nylon?

Actually I am just following in the footsteps of Jim Corenman, who used it in his trav controls for racing to Hawaii (lots of big gybes!) and recommended it to me, and then I also started using it in the snubber.

I use 11mm (or 10.5mm). My preferred variety is New england ropes 'glider' . I find it extremely durable (more so than marine nylon db) with zero cover slippage. I think it is stretchier under significant shock load (due to the 'koremantle construction', which is different than marine db construction) - NER's marine vs climbing data sheets are not directly comparable but I think it is 30% vs 12% stretch. But honestly I just started using it on Jim's recommendation and liked the durability and have never done a real analysis.

Its always been amazing to me that an 11mm rope is perfectly strong enough to be a snubber (and lasts 'forever'), with all the written and online angst about high anchor system strengths and loads.

[Eleven]

The only issue with springy anchor lines is that repeated loading in storm conditions leads to overheating and failure of the anchor rope. Reported on this site.
For climbing the mast SOLO then climbing gear in a climbers hands are probably better than most of us have to hand, but without serious practice and skill invest in a sailors climbing seat/harness. Attaching a safety line can be a problem if your a left hanging, especially solo, many of us simply couldn't climb up a single rope.
Generally in sailing I thought stiff ropes are better, but perhaps that's just for racers.

[thinwater]

Originally Posted by estarzinger

Actually I am just following in the footsteps of Jim Corenman, who used it in his trav controls for racing to Hawaii (lots of big gybes!) and recommended it to me, and then I also started using it in the snubber.

I use 11mm (or 10.5mm). My preferred variety is New england ropes 'glider' . I find it extremely durable (more so than marine nylon db) with zero cover slippage. I think it is stretchier under significant shock load (due to the 'koremantle construction', which is different than marine db construction) - NER's marine vs climbing data sheets are not directly comparable but I think it is 30% vs 12% stretch. But honestly I just started using it on Jim's recommendation and liked the durability and have never done a real analysis.

Its always been amazing to me that an 11mm rope is perfectly strong enough to be a snubber (and lasts 'forever'), with all the written and online angst about high anchor system strengths and loads.

Kernmantle.

I think you can find all of your answers here:
Kernmantle rope - Wikipedia, the free encyclopedia
How to Choose a Climbing Rope: Expert Advice from REI

1. Dynamic ropes come in 3 basic categories: single, half, and twin. Single ropes are 9.8-12 mm, absorb a certain amount of energy per foot (they are rated to absorb about 350 ft-pounds per foot over a blunt edge at least 5 times), and break at about 5,000 pounds, though they are rated for energy absorption, not strength. Within a category they are really quite similar.

2. They have a core made of both right and left hand layed ropes (not braid). This gives increased elongation AND immunity to rotation and hockling.

Really, climbing ropes don't generally have many applications on boats; different horses for different courses.
* They make good anchor ropes for small boats not using a windlass.
* They stretch way too much for most rigging applications (traveler lines excepted--I recently put spectra on a traveler, because I got it for free and the old line was frayed, and it stinks).
* Dynamic snubbers make sense. I recently changed to all-chain (better on the windlass) which made a softer bridle obligatory. Chain is quite harsh in chop. MOST boats use snubbers that are far too strong and too short--they are more interested in durability than function--20 feet is a minimum to absorb wave impacts, since several feet of stretch are desired. A 10,000 pound boat moving at 5 fps would take 2,900 ft-pounds to arrest, so while 8 feet might due a few times, 20 feet would be required for any durability. In reality, a 5 fps surge is pretty severe, but it would have storm winds on top of it.

[estarzinger]

Originally Posted by Eleven

The only issue with springy anchor lines is that repeated loading in storm conditions leads to overheating and failure of the anchor rope. .

mmmm . . . all I can say is that I have not experienced that with my climbing line snubbers, and it has been frequently cycled in storm conditions. It is a different construction than marine line - don't know if that makes the difference.

Those storms have mostly been in coldish weather (rather than the tropics) where overheating would be more difficult to achieve. But I did closely inspect a climbing snubber line after using it thru hurricane Lenny in Antigua and there was no sign of overheating ( I am well acquainted with dashew's findings findings on this sort of heat damage).

[True Blue]

Use the existing static lines as you have them already. Use one for the load and have the second maned and used as a belay line. The belay person can then keep the slack out of the belay line so if there is a fall the shock load will be reduced. Be sure the belay person knows what they are doing. Safety first!!!

[thinwater]

Originally Posted by Eleven

The only issue with springy anchor lines is that repeated loading in storm conditions leads to overheating and failure of the anchor rope. Reported on this site.

That's one of those one-size-fits-all findings that doesn't fit all sizes. The Large 3-strand rope that the Dashews reported to fail may have been aggravated by load cycle heating, but the evidence is circumstantial:

* When new ropes are broken in QA labs, the ends of the fibers often fuse slightly due the the energy release at the moment of failure. This is not a cycle heating issue. The larger the rope, the more dramatic the effect. I think this is a part of what they saw. Heating in-use probably made it more obvious, but was not a major factor.
* The rope in question had endured hours of storm conditions. If heating was a serious factor, why did failure take so long? it should have failed in 10 minutes. Clearly the rope was under strain and had been degraded by the use. However, the heating may have reduced the strength by some small amount (15%--see link below).
* The rope was 3/4-inch 3-strand, not 7/16-inch kernmantle. The larger diameter will hold more heat (less surface per unit stress) and the construction is less efficient.

Perhaps heat was a factor, but the real lesson is that the line was undersize. What are the alternatives? Chain? Polyester? A properly sized nylon rope is still generally the answer, though polyester can be a better answer for larger boats (where the stretch of nylon causes other problems--separate topic).

Heat would NOT be a factor on any rope under 1/2- to 5/8-inch; they simply can't hold enough heat. Larger ropes are a different matter.

Yes, I have some calculations:
Sail Delmarva: Can Nylon Anchor Rope be Melted by a Severe Cycling Load ? Myth Plausible.