Braided Lifelines

[wheels 543]

You mean those suits are just for the pull tests? KM gets me to wear it just about all the time.

Its just that if we start videoing things, we will have irrifutable evidence and we often don't want any evidence at all. Especially when it is me involved.

[rigger 47]

One of last weeks jobs, a gentle 56mm Amsteel Blue. Next to it is a 5mm SuperRound75 (an Italian version of the same thing). The big one has a min break load of 244 tonnes spliced. The big rope is a towline for a superboat currently in town, gawd knows what they are planning on towing though. It's close as the same size as Rigger would have fondled many times in his line of towing, which is the big heavy metals of our waterways. I serioulsy doubt any superboat would have the pull Rigger has........ bollard pull that is, I have no idea nor desire to know what he does with Mrs Rigger

 

You may find the towline sizing is an insurance company requirement and needs to be over speced to replace a wire towline.

 

 

That Amsteel line we used to use. On one that we had finished with we sent (about 3 years ago) off for test and it broke at 39% of 219tonnes (which is the min break load, my book has the 244 as the average).

 

Now using Neutron 8 (sk-75) wwith a slightly higher break point but better chaff resistance.

[Kiteroa 8]

You boys should be videoing all your pull tests anyway, chuck the video in the boat folder and you have a record of the test for future reference should you ever need it.

 

And KM doesn't have any compliance issues with visitors wandering round the workplace or having to get dressed up in those silly black shiny rubber 'safety' suits you insist on wearing when you are conducting a pull test together. The suits alone would squash your bollards they are that tight.

 

Just a suggestion.

 

EE

 

Some testing videos are pretty interesting. For exapmle the Southern Spars EC6 carbon rigging test video is just painfull to watch. It There's this cable on a test bed and it goes from slack to 40% break load in about a second. makes a bang as it takes up then goes slack again. I thought that was it, but no, they did that just a fraction under a million times on the same cable. Then did a controlled break it at the end of the test. It broke at the specified break value, so zero effect from 1 million cycles. As a reference, you'd be lucky to get 100k cycles out of a piece of Ni50 rod.

 

This is why ETNZ and Telefonica use 100% EC6 rigging on the V70's

[wheels 543]

Carbon Fibre does not stress from cyclic loads, which is what makes it so cool.

[Guest]

The lifeline change is an amendment on the YNZ website.

From discussions with Michael Churchouse my understanding is a discrete anti chafe sheath / cover is required.

If you were to argue the double braid was the sheath, any sign of abraision woul be deemed to be wear and the whole thing would need replacing. You also have issues in arguing UV protection etc. Therefore having the separate sheath - whether tube, casing etc is the best option.

[Guest]

You've never taken off and disassembled many old wire thru tube lifelines then J? I'd say easy 50% that 'looked fine' were found dodgy, some serioulsy so, during the deconstruction. Many also don't meet the YNZ Regs. We always pull old stuff apart to see what, if anything, has been happening out of sight. It's damn interesting to see what's been going on.

 

As they say, A coat of paint can hide a multiple of sins.................. and so can that tubing.

 

I would argue -

1 - an over-braid of the load member is a sheath and in fact in many countries do call an over-braided dyneema, as an example, a 'dyneema rope with a sheath'. It just so happens NZ tends to call those same ropes a double braid. On the line that WT has got for one example, the cover is only there for protection, it has no structural input. Being a tight pic it will handle abrasion better then the more normally seen with a looser pic, at the same time it will also up the level of UV protection of the load member.

2 - UV is no more an issue with a quality yarn than it is with that white tubing, possible less so as that tubing decreases in quality as we have noticed over the last few years. There are sound solid studies that do show if you use the right material in the over braid you can stop UV getting to the core at all. Auckland Uni is one place that has looked at just that in depth. I would say that on most good ropes the cover will last longer than much of the white tubing being used today.

3 - A sliced up over-braid will make any issues a lot more visible and make the boater (and Inspectors) think about it harder than is often the case with wire where a lot of issues stay hidden. I see it as quite possible, but probably not that common in reality, to slice the tube and the rope in it but leave next to no visible trace on the outside. That cut in the load member is now hidden from site.

4 - Surely using a product that is extensively and specifically used as a anti-chafe product is better than using one that isn't.......... like that white tube for example. The rope I'm using is 100% made of that very anti-chafe material as the over-braid.

5 - If the term 'discrete anti chafe sheath / cover' is the basis I'd suggest they upsize the requirements. A 4mm Dyneema left in the sun will become 10-15% weaker pretty fast but then stop there. Take a normal SK75 single braid dyneema load of 2000kg, less 15% for splicing, less another 15% for UV reduction, less a unquantifiable amount as many will put it around too small a radius reducing strength a bit more, say another 15%. So it's highly possible for a 4mm rope with a 2T lab load to be more like down to 1200kg in 6 months. Worst case situation obviously but quite possible.

 

Don't forget that in NZ we are tending to get better and better ropes due to competition and technology gains. But at the same time the quality of wire being purchased into NZ is decreasing. What used to be the usual 1770 grade (the most commonly used in lifelines amongst other things) is now knot seen much at all and 1640 or lower is the norm. The grade has a direct relation to it's strength. Also as mentioned that white tube isn't as good today as it was years ago. There is still some of the good stuff but more and more is being brought on price, knot performance. So many YNZ fine lifelines are a lot weaker, more prone to issues and the tube used on them is inferior than it was say 10 years ago.

 

Things are changing fast and YNZ doesn't want to go down the MNZ route of thinking what was fine 20 years ago (or in MNZ case 150 years ago) still applies today. NO!!!! MNZ, Manila rope isn't 'state of the art technology' any longer.

 

But saying all that I am planning on putting some tube over my single braid with a purpose built very high abrasion and UV resistant sheath on it around the cockpit area, it just makes it nicer to lean on. It won't be full length so it can be slid around to check for nasties underneath. Many of the bigger flasher ocean racing yachts and the TP52's use exactly what I'm using, which is only a tad flasher than what WT is planning on using. The only real difference is the material used in the over-braid.... sorry, in the sheath

 

That's my take on it all for what it's worth.

[Battleship 100]

I made my own on the weekend on the little boat as and experiment, will be interesting to see how they hold up they are cheap enough to replace if they don't last to long, just used single braid and put some pvc tubing where they pass through the stanchions. Interesting the old wire ones had a lot of broken strands that we didn't notice until we pulled them off.

[Guest]

17.17 The minimum diameter lifeline wire or rope (single braided Dyneema, Spectra, Vectran, Dynex or similar material protected from UV and chafe by a sheath: ...

While probably fine in real life Mr Willow, I'd argue your handy work won't meet the above requirement. I'm knot seeing a sheath.

[wheels 543]

Here ya go Paul. You can see the shadowey lines where the 4.5 turns were.

[Guest]

And was Mr Wheels surprised a bit of little string could do that? Oh Hell yes! It was funny watching him trying to get to grips with it all

 

Mr Wheels has found a new hobby, mangling metal into art forms just using flimsy looking bits of string.

 

He gets to mangle some chinese chain tomorrow. A nationwide chain that should know better is to tight-arsed to supply an equally tight arsed helichopter, again another who should know better, proper tested good reliable stuff.

[Battleship 100]

17.17 The minimum diameter lifeline wire or rope (single braided Dyneema, Spectra, Vectran, Dynex or similar material protected from UV and chafe by a sheath: ...

While probably fine in real life Mr Willow, I'd argue your handy work won't meet the above requirement. I'm knot seeing a sheath.

This boat is for harbour racing Cat4 only so doesn't require lifelines at all, just makes the crew feel safer.

 

I figured they have used it on Melges for years so would probably be ok.

[Battleship 100]

Interesting that the ISAF regs differ from the NZ ones

 

"a) Lifelines shall be of :

- stranded stainless steel wire or

- Single-braided High Modulus Polyethylene

(HMPE) (Dyneema®/Spectra® or equivalent) rope

 

 

This is from the 2012 -2013 special regs, I wonder if the NZ ones will change to reflect this in the next issue?

 

I can understand the chafe protection but the UV protection requirement is a little odd, given the well documented effects of UV on the stuff overseas.

[PaulR 3]

Wheels: Thanks for the photo. Do you have another showing the size of the bollard from end on I assume it was hollow

[wheels 543]

No it has two steel plates welded each end that the test beds chain couples to.

[Guest]

That bit of tube is only about 200mm long, hollow but very heavy walled and has 2 thick steel plates welded each end.

[Guest]

In response to both my and another Crewers desire to have sexy lifelines, today we did some testing on them to suss a specific rope I like and to see if we can make lifelines metal free.

 

Pleased to announce that after some playing with Mr Wheels, fugitively only thank you, Yeap we sure can. 100% metal free linelines that match the strength of wire ones and totally comply with the YNZ Regulations.

 

Now the interesting bit is just how much lighter they will be. We'll know for sure by weeks end after we have done the other said Crewers boat. You all know him, he's called Mr Guinea Pig..... or he was until an hour or so ago

 

But he can rest assured his lines will be exactly the same as mine in every way and I'm anal about shite like that :thumbup

[Megwyn 2]

after some playing with Mr Wheels, fugitively only thank you,

 

[Guest]

Yeah I noticed that bit thought what the hell

 

We run a I make it, Wheels breaks it programme now. I just can't make it as fast as he can break it

[wheels 543]

after some playing with Mr Wheels, fugitively only thank you,

No I wasn't being held against my will, nor were we playing Prison Games like Hide the Soap. KM meant Figuratively

[Guest]

I would think that in 99.9% of lifeline installs the stanchions are the weakest link. I'd say that is probably a good thing as the lifeline will still hold you even if you are hanging off the side with 2 stanchions in close company. If the lifeline breaks stanchions suddenly become 100% pointless unless you are fast enough to grab one as you fall past it.