Reefing lines BEST?

[Dudeman]

climbers use a dynamic rope that they climb on. All other slings, chordage etc. is static.

[Wotname]

Originally Posted by GMac

......

PS. Spectra and Dyneema do have slight differences but none that 99% of people would see in real life.

OK, I am normally (always?) in the 99% group but like to take any opportunity to try to get partway into the 1%ers.

If you are willing, could you detail some of the differences (either here or elsewhere - don't want to hijack the OP thread).

[Hubec]

In a gross divergence from internet forum norms I'll not only give my opinion, but also provide an actual reference! The Waterlines column in this month's SAIL magazine touches on this issue. The slab reefing system of a test boat was rendered useless by polyester reefing lines. The resulting stretch rendered the boat unsailable in just 35 knots of wind.

Reefing lines must be extremely low stretch to be of use when they're needed most.

[GMac]

Originally Posted by Hubec

The Waterlines column in this month's SAIL magazine touches on this issue. The slab reefing system of a test boat was rendered useless by polyester reefing lines. The resulting stretch rendered the boat unsailable in just 35 knots of wind.

After using polyester for many miles on many differing boats I do struggle to see how they got to 'unsailable', that's a pretty big call. Even way way back in the day when it was 3 strand it still worked even if it did need tweaking up often.

Actually just remembered, I brought a 60fter back from Brisbane just before Xmas and it had 3 strand 'something' reefing lines. That old and mouldy I couldn't tell what it was. They had to work for 24hrs odd but sadly only made 18hrs odd before wearing through, which I put down to age more than anything. Quick swap out and good to go again but as usual, I would have preferred if it wasn't at 2am. Why do things like that always happen in the early hours???, most annoying.

Maybe SAIL were using some of the dodgy polyester that is creeping out there lately. Real sharp price but still bloody expensive as some has alsorts of crap as a core. Looks just like real stuff from the outside but look inside and I've seen a paper like substance rolled up and one had stuff that looked like shredded carpet, both would have massive stretch and strength issues. It's trapped many people.

I think those with decent polyester shouldn't panic.

Wotname - I'll dig out a bit I did for someone on the differences for you. I'll even try to update it with info on the new SK90 that is arriving. SK90 is a 'grade' I suppose you'd call it of the raw material. Started at SK60/62 which has pretty much been phased out in favour of SK75. Mostly just a strength thing.

[Wotname]

Originally Posted by Hubec

...The slab reefing system of a test boat was rendered useless by polyester reefing lines. The resulting stretch rendered the boat unsailable in just 35 knots of wind.

Reefing lines must be extremely low stretch to be of use when they're needed most.

Gee that must explain why I have not been able to sail very well everytime I put a reef it over the last 25 years - I was using the wrong reefing line.

Referenced opinions are OK but the argument fails the commonsense test.

In this case, the reefing lines under test stretched too much, the reefing lines were polyester, polyester is known to stretch, therefore the polyester is not suitable for reefing lines. This is not the only possible deduction from the facts. What else do we know - well, polyester has been used for decades for reefing lines, sailors have reefing and sailing satisfactory for decades, therefore polyester is OK for reefing lines. So we have a discrepancy, therfore logic has failed or at least one "fact" is wrong or the conclusion is flawed. Experience tells me that logic doesn't fail, the facts (in this case) seem to be OK so perhaps the one conclusion is wrong.

Commonsense should kick in about here and tell us to look deeper into the conclusions.

Gmac went straight to the heart of it and his version seems to fit the known facts. As well as that, it makes sense (commonsense?).

Of course new technology will make older technology redundant, but can't turn older products into unusable items.

Look forward to the info Gmac - thanks

[Alan Wheeler]

I can't tell you what the differences in use are, but I can tell you the chemistry differences.
Vectran and Spectra is made from a Liquid Crystal Polymer or "Aromatic Polyester". It has really good UV resistance, starts to lose strength from 220degC (which is really impressive) and melts at 330DegC.
Dyneema is quite different. It is made from Ultra High Weight Polyethylene. Or for short...UHMWP. This material has the highest impact strength of any plastic. It is virtually self lubricating and thus, has very low friction and thus very low heat generation.

[Wotname]

OK, I had it a little different: that Dyneema and Spectra are both high-moduls polyethylene. Dyneema is trademark of DSM (European company) while Sprectra is the trademark of Allied Signal (USA).
Vectran is the liquid crystal polymer, invented by Celanese Acetate and now owned by Kuraray Co.

Perhaps I have it wrong (again.......)

Gmac???

[Oceansandmts]

And the winner is: Wotname.

[Wotname]

Do I get a Star Reefer stamp?

[roverhi]

FWIW, just spent a day sailing in windy SF Bay. Winds over 30 mph. My 7/16" Sta-Set clew reefing lines did just fine. If they stretched, I couldn't tell it. Sail was flat even when overpowered at the second reef. BTW, went with 7/16" over 3/8" for chafe reasons. Plan on doing some long distance cruising and you do get chafe when reefed for long periods. 3/8" probably would have done just fine. 3/8" tack reefing lines didn't stretch noticably, either.

If you like to waste money, by all means use hi-tech lines. I suppose if you are a weight nut, going with too small to handle hi-tech would have a place.

Aloha
Peter O.

[Alan Wheeler]

Ooops, your right Wotname. I was supposed to say Spectra and Dyneema. My Brain just ain't what it used to be.

[Wotname]

No problem Mr Wheels and I am also very familiar with the "brain" issue!!!!

[svTOTEM]

GMac - Unless Vectran has changed, it has terrible UV propeties. I'm surprise to see it used in the cover.

A great way to improve a reefing system is to attach a block at the leech reef points. Use webbing and handsewing to attach the block to the pressed in ring. The block significantly reduces the friction at the high load end: 1) making the last 2' of setting the leech reef easier 2) reduces (maybe eliminates?) the chaffe on the leech reef line.

[Wotname]

Again I understood Vectran to have an very high resistance to UV which is one of the reasons NASA uses so much of it in space missions????

I have wondering about using blocks as you describe - does the block cause any noticable chafe to the sail especially when flogging or is this not a problem?

[svTOTEM]

I've never seen a chaffe issue on the sail, and minor chaffe on the webbing that attaches it. The block should be up close to the ring. The handsewing should be such that the webbing connecting the 2 should be rigid. If you reef often, you should inspect, and probably replace the webbing yearly - much cheaper then replacing your reefing lines.

As for Vectran, if I remember right, it was first developed for the shipping industry. The UV characteristics are worse then araimid fibers (kevlar). This is why it was never a viable sailcloth. Of course it is expensive, but in the grand prix racing world, money is not the limiting factor. If found the following graphs from the Vectran website -
http://www.vectranfiber.com/pdf/24Pa...al61206-16.pdf