Monday, January 17, 2011

I'm on the lookout for "stuff" for the boat.

So when I was in the local Bunnings store ( its about the same as Lowes or any of the other big box nightmare hardware stores) and I saw a specials box with bundles of good looking 10mm ( 3/8in) braided rope  in it, I looked.  Rope, expecially that sort of size and looking like yachtbraid?  Well, there is always a place on board for that. Gaff rigged boats use LOTS of rope, in fact I think anyone owning a big gaff ketch will just about need to buy a rope factory to go along with it.
Anyway, the price on these 30 metre ( 100ft) lengths was amazing, only NZ$8 90,  ( about US$6 00 or so). At that it was never going to be the real deal, the good stuff, but how bad could it be?  The colour for starters is not what you'd want to see on a traditional gaff rigged classic, but maybe it could be used as a dinghy painter, or to tie up to a jetty, or just as spare.

I bought two, brought them home, and peeled the outer cover back to see what was inside.  Ahah! The core is not braided, its a bundle of split fibre, just an extruded strip of plastic about 50mm ( 2 inches) wide which has been rolled laterally into a round bundle, and the cover woven over it.
Thats not an automatic disqualification in itself, but it does mean that when the rope is under load there will be a strong tendency for the core to slide within the cover, bunching the cover and locally stressing the core.
it also means that its prudent to put a whipping on the ends of the rope to prevent pulling the core through the cover and away from the end.
 I'd say that just melting it together as is the usual practice wont be enough, so put a whipping on it, and stitch the core to the cover with a needle and heavy thread.  I dont think the usual 8 or 10 times through will work in this case,  try 20 or so passes with the needle then a 50mm whipping over the top.

Next, I put the end of the rope in a flame, each different type of fibre has a distinctive way of burning , or a particular smell and this is not the high strength polyester or nylon rope that yacht braid is usually made from, it melted at a very low temperature, burned very easily rather than just melted and did not smell the same as my samples of either polyester or nylon braid.
It did though smell much the same as some cheap packaging twine that I think is polyproplene.
Here are some clips from a site which gives the properties of rope fibres.

Polyester looks and feels much like nylon, however, it has considerably less elongation and does not have increased elongation when wet. Polyester ropes are unaffected by water and are impervious to rot and mildew. They are more resistant to acids, but are sensitive to alkalis. Polyester is naturally quite UV resistant. Its melting point and performance at elevated temperatures are comparable to nylon.

Polypropylene is the least expensive of the common rope fibers. It is very light and therefore is often used where floatation is required. It is unaffected by water, and generally has good chemical stability. However, it is considerably weaker than nylon and polyester, and tends to deteriorate rapidly from UV radiation. Polypropylene ropes have a low melting point, and tend to exhibit high creep (gradual elongation under load).

You can see that Polyester is very good stuff for everything yachting except anchors where some stretch is a help in absorbing shock loadings, and polyproplene is not much good for anything except tieing up a horse.  A small one at that.

It looks and feels nice, but be aware, dont get caught.



  1. I've bought a couple of rolls of this stuff myself, as you say, how bad can it be. Dont worry about the colours, a month in the sun will see it fade to a pale silver. I use it to hold down my boat cover.

  2. I would say have several of them around. For that kind of price, it is great to have disposable lines to temporarily lash things down, use to rescue stranded seagulls and the like. It is also the perfect thing to have when someone wants to borrow a line.

  3. I've sailed my little gaffer (15ft long, 110 sq ft sail) rigged with this line for 4 years. The cover does stretch and slide off the core if th ends aren't whipped and heat sealed. Red and green colors fade away the first summer. The second summer it becomes stiff and unpleasant. It didn't work well for halyards, and never for anchor lines, but for sheets was OK. Chafes easily, making for poor mooring lines. Easy fiber test: nylon and polyester (dacron or called "yachtbraid") sink. Polypropolene floats. Nylon smells vaguely like onions when burned. Polypro is cheapest and weakest, then nylon, then polyester

  4. Is this the same stuff?

    Bought something similar 3 years ago. UV killed it in 6 months. No more cheap rope for me.
    AJ in SA

  5. I suspect that its the same product, if not, very similar.
    Mine has been banished from the boat, my wife now has several different tie up and lunging ropes for her miniature ponies where the poor strength and durability will not cause problems.
    The risk is that because they look like other "proper rope" then someone will use them in a situation where they will not be up to the task.

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  7. I was looking at this rope at Bunnings. A guy came and told me not to bother. He tried using it on his farm and it fell apart in no time. Including tying up his goats. They had it shredded in about five minutes.