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It is said that a semi-static rope should be submerged for 24 hours before first use.

Why is this, and is this before every first use ?

Paul Lydon
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Nick
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2 Answers2

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Yes, it is accepted practice to wash new Semi-Static rope (or Single Rope Technique/SRT Rope as it is known by cavers).

Dave Elliot is a highly respected SRT expert, and he wrote the CNCC Rope Care page, which says:

There are two reasons why new ropes are best washed before use. Washing removes the anti-static lubricants used in manufacture and also shrinks the rope. This serves to compact the sheath and tighten it onto the core, stabilising the rope and perhaps improving its wearing properties a little.

and

When first soaked all ropes, particularly nylon ropes, can be expected to shrink by various amounts up to 8 or 10%. Obviously it is as well to roughly determine the shrinkage before cutting and marking ropes for length. Never the less, the rope will continue to shrink (at a much lower rate) throughout it's life, mainly due to the effects of the mud which inevitably penetrates the sheath.

Toby Speight
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Paul Lydon
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  • This goes only for the very first use, or every first use? (See my comment on Roddy's answer). – Nick Aug 07 '14 at 12:09
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    The washing before very first use of a new rope is recommended for the reasons given in my answer. After that, the rope would be washed if it becomes dirty after use (which happens quite often in caving!). – Paul Lydon Aug 07 '14 at 12:14
  • so the rope should get wet sometimes ? For example if the rope stays dry for 2 years and you restart using it then, should it be submerged then again or not ? – Nick Aug 07 '14 at 15:17
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    You wash the rope after purchase and before use to remove anti-static lubricants used in manufacture and to shrink it. Thereafter you wash it when it needs washing. I cannot make this explanation more clearer! – Paul Lydon Aug 07 '14 at 16:24
  • thanks, Just checking wether it needed to be reshrunk or not ;). – Nick Aug 08 '14 at 08:58
  • Short extra thing I was wondering, why does semi-static rope shrink thourghout it's lifetime? Shouldn't it get longer because you stretch the fibers? – Nick Nov 09 '16 at 06:58
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They shrink, apparently. For example, Beal's Precautions says:

Before first use, soak the rope and leave to dry slowly. It will shrink by about 5%. Take this into account when calculating required lengths.

And first use means just that: The very first time the rope is used.

Toby Speight
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Roddy
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  • Yes, I read on Petzl that this submerging of the rope will also improve the bond between the core and the mantle. So in that context the "first time only" makes sense.

    But the preshrinkage makes me wonder if it's not meant to say "before every season". Won't the rope unshrink a little bit?

     – Nick Aug 07 '14 at 09:02