Rolling Hitch on Snubber

[estarzinger]

Regarding climbing line . . . . I think I have said this before but, for Hawk, it has proven sufficiently strong up to cat 1 hurricane strength. And it's cat 1 hurricane failure was chafe on the cover, which should not be a failure point for my current snubber design.

I would be interested if anyone could directly compare the elasticity and breaking strength for the same size (say 10 or 12mm) climbing line and 8plait nylon? When I look at the data sheets, it seems that the climbing line is tested to different standards than marine line, so I can't quite figure how they directly compare. The core on climbing line is so different than brait in construction i dont have a good intuitive sense of how they might compare on fundemental characteristics. I really like the climbing line, and have had good experience with it, but I really don't need the cover for chafe protection anymore, and I could splice brait (I think the clear weak point in my current version 1 snubber is the sheet bend). Edit: the climbing line cover does provide UV protection . . . Not sure how important that is . . . The snubber does get a lot of UV.

Second question - anyone know of splicing instruction for "kermantle" climbing line?

By the way, it's not much of a test so far, but I pulled the soft shackle up this morning, and it did not seem pinched in the loose link, and looked "new" with not even a smudge of wear.

[Bash]

Originally Posted by Andrew Troup

In fact for me, except in the most extreme conditions, or on a boat whose chain is light in relation to displacement, a snubber is a short affair rigged with minimal 'give', intended to keep the noise of chain rumble from telegraphing through the bow roller more than anything else. And pretty much any type of line will serve.
.

Same here. The snubber's first task is to relieve strain on the windlass. Its second task is to promote slumber by dampening chain rumble. At the point where it prevents chain jerk, it's earning extra credit.

[Dockhead]

Originally Posted by Bash

Same here. The snubber's first task is to relieve strain on the windlass. Its second task is to promote slumber by dampening chain rumble. At the point where it prevents chain jerk, it's earning extra credit.

You don't have a chain stopper, Bash?

[Bash]

Originally Posted by estarzinger

Second question - anyone know of splicing instruction for "kermantle" climbing line?

For climbing applications, the only splicing instruction is "don't do it."

Kernmantle is basically double-braid. "Kern" refers to the core, and "mantle" refers to the exterior sheath. In the early days when we were switching from three-strand "goldline" climbing rope, "kernmantle" referred to anything other than three-strand.

[Bash]

Originally Posted by Dockhead

You don't have a chain stopper, Bash?

I'm a chain-hooker.

[nigel1]

A few lines pretty much unrelated to most of the recent discussion.

1) I like the idea of the soft shackles, they were not something I had paid much attention to in the past, but the use in a snubber set up seems good.
In the UK, it seems Amsteel is pretty much unattainable unless purchasing a full coil. (Although I have heard that Reddon Marine might ship to the UK)
Seems the alternative we have here is Marlow D12. Expensive string, so before attempting to make a snubber from this, can anyone suggest a cheap line of similar CONSTRUCTION to the Amsteel blue which could be used to practice the splice and stopper knot.

2) Snubbing is all about reducing the shock loads on the ground tackle and the boats mooring arrangements. Seems to me a well designed riding sail would assist in this. Any thoughts or comments. I have a small riding sail which came with the boat, but according to the specs, its only good for a boat up to 30', so I have a friend who is making me a larger one. It will be rigged from one of the split back stays and led sort of diagonally across the deck.

3) last question for Evans, your website indicates that the best pubs are in Kinsale. Any pub in particular?, it needs to be suitable for my Mum (who is oirish)

[Dennis.G]

Originally Posted by estarzinger

I was thinking if I want more snubber or more elasticity I could attach a piece of nylon from to the inboard end of the dyneema and take that nylon to a mid-ships cleat. I doubt that will be necessary but it's an option.

I had thought of same thing (although a small line to midship cleat on each side to keep the joining knot centered on foredeck). My main thinking there was to keep a chain hook closer to the boat and off the bottom.

The concern that came to my mind was that where the dyneema crossed over the pointy end of the boat it would be subject to a lot of sawing (in and out) chafe motion as the boat surged about. Think it best that the elastic part be kept overboard and that line onboard be as static as possible to reduce chafe.

[sabray]

I use endura braid on my mooring penant. Its 12 strand dyneema with a polyeter cover. I added a outer chafe sleeve at the chocks rated at 19,000lbs per line. it is 2 12mm lines eye spliced both ends to 3/4 inch nylon double braid rated at 20,000lbs eye spliced both ends one with thimble and crosby shackle which attaches to mooring provided by marina. overkill playing with this setup on a snubberso the chafe points are well protected while the snubbing friction part are in the water or at least getting wet but not chafing. Attached to chain with amsteel blue end spliced loops. think anchor hitch with 2 wraps will be knot of choice. been using a bowline because I ran out of creativity.

[thinwater]

Originally Posted by Bash

For climbing applications, the only splicing instruction is "don't do it."

Kernmantle is basically double-braid....

No. And this distinction is important because dynamic rope does not behave like double braid. It's energy absorption capacity is greater, and though the initial stretch is less than 3-strand (limitied stretch under body weight is desirable if you are Jumaring on the rope) the total energy absorption is greater.

Most dynamic climbing ropes have a fine mantle (very hard to splice because it will not open up--ths is to prevent snagging on rocks) with a core of 8-12 twisted strands (like 3-strand) 50% RH and %)% LH (to prevent rotation).

At least all of the those I have cut on rocks were built that way .

___________

What a re the drawbacks of dynamic ropes for docklines/snubbers?

• Price
• Limited abrasion resistance. While good, the mantle is thinner than double braid. Quite acceptable with good chafing gear.
• Impossible to splice. When "splices are required (climbers always knot, as a splice could snag in a crack when hauled up a cliff) in industry a swage is used.
• Limited size range. generally 7-11.5 mm. There are 3 classifications: single, double, and twin, and they are tested with different falls.

Bear in mind there are other "climbing lines" sold that are either static lines or accessory cords. These are both more like yacht braid. A dynamic line will always be identified by a fall rating, not strength.


What is the strength rating of dynamic lines? For snubbing applications, the fall rating is more relevant. But about the same as a nylon line of equivalent diameter. No magic there.

[s/v Jedi]

Originally Posted by nigel1

A few lines pretty much unrelated to most of the recent discussion.

1) I like the idea of the soft shackles, they were not something I had paid much attention to in the past, but the use in a snubber set up seems good.
In the UK, it seems Amsteel is pretty much unattainable unless purchasing a full coil. (Although I have heard that Reddon Marine might ship to the UK)
Seems the alternative we have here is Marlow D12. Expensive string, so before attempting to make a snubber from this, can anyone suggest a cheap line of similar CONSTRUCTION to the Amsteel blue which could be used to practice the splice and stopper knot.

2) Snubbing is all about reducing the shock loads on the ground tackle and the boats mooring arrangements. Seems to me a well designed riding sail would assist in this. Any thoughts or comments. I have a small riding sail which came with the boat, but according to the specs, its only good for a boat up to 30', so I have a friend who is making me a larger one. It will be rigged from one of the split back stays and led sort of diagonally across the deck.

3) last question for Evans, your website indicates that the best pubs are in Kinsale. Any pub in particular?, it needs to be suitable for my Mum (who is oirish)

D12 is the ticket for Marlow 12-strand Dyneema. It is the same as the ones discussed here, may be even stronger (SK78 IIRC). The soft shackle that I put pictures of on-line, only needs 4' of 3/16" Dyneema so the price is not too bad.

You should check out commercial fishing suppliers as they also use this rope instead of wire.

[nigel1]

Originally Posted by s/v Jedi

D12 is the ticket for Marlow 12-strand Dyneema. It is the same as the ones discussed here, may be even stronger (SK78 IIRC). The soft shackle that I put pictures of on-line, only needs 4' of 3/16" Dyneema so the price is not too bad.

You should check out commercial fishing suppliers as they also use this rope instead of wire.

Cheers Nick, I'll be back into Aberdeen day after tomorrow, I'll check this out with the skippers on whats left of the fishing fleet.

Edit: Just had a word with the Mate, his cousin works for Jackson Trawls in Peterhead, so may be onto something here.

[Dockhead]

Originally Posted by Bash

I'm a chain-hooker.

No problem. But don't you have anything (stopper, hook, strop, whatever) between your ground tackle, and your windlass, besides your snubber??

[estarzinger]

Originally Posted by nigel1

3) last question for Evans, your website indicates that the best pubs are in Kinsale. Any pub in particular?, it needs to be suitable for my Mum (who is oirish)

Can suggest two: Spaniard and The Bulman

However we were last there in 2000, so things might well have changed.

The town is jammed full of pubs. Our experience was that they were 'better' in the winter when they became more 'local' and less tourist oriented.

[nigel1]

Originally Posted by estarzinger

Can suggest two: Spaniard and The Bulman

However we were last there in 2000, so things might well have changed.

The town is jammed full of pubs. Our experience was that they were 'better' in the winter when they became more 'local' and less tourist oriented.

Cheers Evans, the Spaniard was top of my list, I'll be stopping over for 3 days, so time to check out some more.

[JonJo]

Two recommendations for climbing line loops, a double figure of eight knot (which is huge) or strangely - sewing (which is 'close' to a swage). I'm sceptical of sewing but its completed by the cordage maker and rated higher than the knot - not sure if a sailmaker could sew to the same strength.

Jonathan