Thursday, April 10, 2008

Parted line

Parted lineOne of the crane barge lines which hold us to one of two mooring buoys parted.

One parted line is not too much of a problem, as Lady Jane is tied to both the mooring buoys and the crane barge and the crane barge is normally tied on with two lines on either buoy.

Still, with one line parted, there's inevitably more strain on the other lines.

It took me a while to notice that it was a parted line which was responsible for Lady Jane lying slightly differently to normal.

I re-tied the mooring line back up to the crane barge, but with the wind and tides there was no way I could get things back to normal by hand. No matter how hard I tried.

The picture shows the cunning use of a prussic, a very handy knot learnt during the climbing things phase of my life, and my trusty chain block to persuade the combination of Lady Jane, the crane barge and Lilagina back to where they should be in relation to the mooring buoy.

It all worked out nice and easy, and most importantly of all - safely.

Unfortunately, one of the other crane barge lines now seems jammed underneath Lady Jane somewhere. The result of the line being pulled behind Lady Jane on fast spring tides.

Though I doubt it will happen, I'm hopeful that the line will work free of it's own accord. The alternative is a cold swim in the river with a sharp knife.

12 comments:

  1. Anonymous2:44 PM

    >> most importantly of all - safely

    The type of chain-hoist pictured is not normally intended for horizontal pulling. It may have a dire warning on it to that effect.

    The design may rely on the weight of the chain exerting force in a certain direction -- ie: downward -- to ensure the chain follows the proper engagement path.

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  2. Hi Anonymous

    I'm not aware of any warnings about horizontal pulling on my particular chain block.

    I bought it from new, so would have read all the warnings at some point.

    Please bear in mind we are not talking about that much force here anyway, just a steady pull.

    I should think that once there is a load on, the direction of pull, whether horizontal or vertical, becomes academic, except for the small handling chain, which may need a little more care in feeding it through it's guides.

    With no load, I did notice that 'pulling' the slack main chain through was a little tricky, as it did not seat as well in the guide rollers. No more problem than the chain block can be in normal operation though, and easily resolved.

    Regards

    Tim

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  3. Ah Ha! the old prussic knot very handy when one wants to climb a mast or shrouds (I used to once, no I did really) but on rope I now prefer Dumars/ascenders and slings when climbing vertically. many sailors wouldn`t know of a prussic knot. Oh! its a great knot for what you used it for too particlarily if you want to cast off with the wind pushing you off and the mooring line caught on the cleat, . just take the strain on a winch loosen the mooring line and cut the prussick not line with a knife, and Hay ho off you go :o)) and only a foot or so of line lost. But then you know tnat already :o))

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  4. Hey tim, I use chain blocks sideways all the time, and I agree with you, Robin and Larry do it too. I know you're not REALLY supposed to use them like this, but once pulled taught they're fine, and safe. Just needs extra care to register the links of both chains as you go. And I'm bending thick steel with the buggers (see my latest post for out of focus example pic), I do however need more force, so I'm off to buy some 20 ton jacks today, which are useless for persuading parted lines.. Anonymous will probably think we're both reckless danger monkeys now.

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  5. Hi Rob

    A good story. The prussic knot is just right for such occasions.

    For such a simple knot, I'm surprised it's not more widely known.

    Tim

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  6. Hi Seb

    Those chain blocks are so useful for so many things.

    I bought mine with a 3m (9 ft) drop, to cater for the depth of Lady Jane.

    Cheers

    Tim

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  7. Anonymous1:14 PM

    Your both reckless danger monkeys....use a comalong

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  8. Anonymous2:51 PM

    I know people use chain blocks for pulling all the time and mostly don't get hurt.

    But if you are buying a tool specifically for pulling and binding, buy the right thing: a lever hoist. This is a really fancy one:

    http://www.coffinghoists.com/assets/gmodel.pdf

    You will see that, in general, lever hoists are rated as "suitable for pulling applications" while chain hoists are not.

    Bloody danger monkeys! I'm paying into your NHS coverage you know. :-)

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  9. Hi Anonymous - comalong, I've always liked that name :)

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  10. Hi Anonymous

    That lever hoist looks like a pretty handy piece of kit.

    I wish I had the money to buy one of everything. The chain block is a good all rounder for the uses I have.

    As to the NHS, hmm that is a wonderful service which, like the RNLI, I hope never to have to use.

    Cheers

    Tim

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  11. Anonymous9:11 AM

    The reason more sailors don't know the Prussic knot is that they have a perfectly good knot for this purpose already - a rolling hitch. That's what I'd use for this job - easier to tie, too.

    (I'd stick with the prussic for climbing though.)

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  12. Hi Anonymous

    Thanks for that. I'm learning all the time!

    A good knot, perfect for the job, can make all the difference.

    Regards

    Tim

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