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There
is no question that the life of a caving rope is very tough indeed;
stretched, knotted, squeezed in metal devices, soaked, muddied,
and hauled over rough rock, the punishment suffered is relentless.
Suspended above the abyss by a single vulnerable thread, a cavers'
rope is vital to his continued existence, dependence on rope absolute.
Yet what does a caver care about the rope that he trusts his life
to? Rock climbers carelessly trampling a climbing rope on sharp
rubble or dragging it through grit would rightly be considered daft.
Many cavers appear to assume that this is acceptable practise, even
though the two types of rope are made from the same material.
Choice
of Rope
The optimum
rope for normal use is 10-10.5mm diameter low stretch nylon rope
designed for S.R.T. Strong enough to provide a good safety margin,
sufficiently robust enough to withstand several years use, yet relatively
light weight (60-70gm/m). This same rope is suitable for all purposes
underground (traverse lines, hand lines, lifelining ladder climbs)
apart from lead rock climbing.
Such
harsh treatment demands the best quality rope available, so buying
rope which is unknown and nay turn out to be inferior, just because
it is a little cheaper, is foolish! It bears repeating that on
each pitch the cavers' life depends entirely on the rope, no
back up of any sort exists if this breaks.
Special
applications call for special ropes; for intensive use by clubs,
or use by rescue teams involving heavy loading and where a good
grip is called for, 11mm ropes are appropriate. The same applies
to very deep tree hanging drops (l00m+), especially when to save
time these are climbed in tandem. In all these circumstances the
reduced bounce and general solidity of the thicker rope is a great
comfort, the penalty is extra weight and bulk (70-80gm/m). More
serious considerations apply to small diameter ropes, of less than
10mm diameter. Of course 9mm ropes are lighter, more compact, and
initially strong enough, but the weight saved is hardly significant,
while the reduction in safety margins is considerable, Heavy shock
loading and abrasion damage apart, imagine for example, the prospect
of mid-rope rescue of an injured caver on a well used 9mm rope!
We might well question the wisdom of using a rope which is only
safe in certain circumstances. Besides, instead of proving cheaper,
because these ropes must be renewed more frequently, over a period
they turn out to be much more expensive.
There
is also no question that lack of care and attention can be equally
dangerous, it is just as important to care for ropes properly as
to select a suitable rope in the first place. Make no mistake,
cavers neglect the rope only at their peril.
Transport
Ropes
should always be carried underground in a tackle sack. A well-designed
sack, besides being far easier to handle than coiled ropes, largely
protects the rope from damage. Surroundings are harsh and it makes
much better sense to wear out the sack than the rope. A rope which
is muddied on the way to the pitch, has the mud forcibly ground
into it in use. Even fine silt rapidly wears out metal equipment
and rope alike, and once embedded it is impossible to subsequently
remove all the silt particles from the rope.
Lining
the sack with a watertight stuff sack closed with a rubber band
will exclude water and the damaging grit it carries with it. The
rope is both lighter and stronger for remaining dry. On the surface,
ropes packed in sacks are protected from sunlight, rather than slung
across the top of a rucksack in the full glare of the sun.
Washing
and Inspection
After
each trip, ropes should be washed and inspected for damage. Apart
from normal surface abrasion which is more or less obvious, the
worst thing that generally happens to a rope underground is getting
it muddy, or more specifically, using a rope which has become impregnated
with mud. There after each time the rope is loaded or squeezed through
a descender a multitude of microscopic particles of grit are forcibly
ground into the fragile yarn filaments and some weakening is inevitable.
Thorough washing is important to remove as much as possible of this
mud which abrades the internal fibres of the rope, while making
it stiff and difficult to handle. A rope cannot be properly inspected
for any surface damage which may have occurred until it is clean.
Superficial mud can be removed by simply sloshing the rope around
in running water, perhaps in a stream by the cave. This is not always
sufficient, however, more stubborn dirt calls for pulling the rope
a few times through a rope washer, until the water runs clear.
Throughout
most of the caving regions of the U.K., streams of fresh water abound
in the hills. Following a trip, washing ropes (and why not other
equipment too?) in a nearby stream, or one located in a convenient
place by the roadside, still dressed in wellies, over suite and
gloves, is not an unpleasant task and takes but a few minutes. This
is preferable by far to arriving home tired and dumping the gear
in a corner, only to be faced later in the week by a heap of muddy
rope and by now rusting bolts and Krabs. Far better to wash the
ropes before leaving the caving area, so back at base they only
require hanging up to dry.
For maximum
cleanliness, from time to time, ropes can be washed in a washing
machine, normal (cool wash) temperature 30'C. This tends to be a
long Job because most machines will only take a few ropes each load.
Undue tangling can be prevented by loosely plaiting (chaining) the
ropes or stuffing it into a mesh bag. Adding normal amounts of fabric
softener in an attempt to keep the rope supple is not harmful, but
because the rope's stiffness is due largely to impacted silt particles,
this doesn't soften it much either.
To set
minds at rest regarding any weakening effects due to repeated machine
washing, remember that the same bulk fibre used in caving ropes
is that employed in ordinary clothing designed to be washed every
few days. Note that because the normal soiling caused underground
is neither 'organic' nor greasy, adding detergent is fairly ineffective.
Better if ropes are washed in clean water only.
After
washing, ropes should be carefully inspected for damage or signs
of excessive wear. The best method consists of running the rope
through the fingers a little at a time, flexing it and feeling for
soft spots or regions of reduced diameter as well as looking for
more obvious damage. If necessary, the rope should be cut and remarked
before being stored.
Contamination
Rope
materials in general are particularly stable polymers affected by
very few common chemicals, never the less, it is well known that
nylon is severely affected by quite dilute acids, and that polyester
are attacked by strong alkalis. The most likely source of contamination
being leaky mining accumulators, a form of lighting still favoured
by many cavers in the U. K. In both instances irreversible damage
to the fibres takes place within minutes, so subsequent washing
is no answer.
Such
damage is virtually un-detectable to the eye, which means that the
only real safeguard against this insidious menace lies in avoiding
any possible contact. Relative 'acid or alkaline-resistance' of
different materials has long been a mis-guided factor in many cavers
choice of rope and harness. Underground it is quite impossible to
always keep rope, cows tails and harness away from the lamp battery
while struggling in crawls and awkward pitches. To be sure of remaining
safe any item even suspect of being contaminated must be scrapped.
So there is no doubt at all about this advice, peace of mind
lies only in adopting a more suitable lighting system.
New
Ropes
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 it's
wearing properties a little. Soak the rope in clean water, drain
and squeeze out surplus water by pulling the rope through an anchored
descender. Repeat process two or three times, each time pulling
the rope through the descender in the same direction. Hang the rope
up to dry for a few days. Later cut off any loose sheath that may
have crept along the rope and melt the ends to prevent any unravelling.
This procedure helps prevent sheath slippage during the initial
few trips until sheath and core are properly bedded.
With
some softer constructions, the manufacturers find it difficult to
match the sheath and core tensions exactly, so especially when used
for abseiling, the sheath slips a little in relation to the core.
This is not much of a problem. For the first few trips just ensure
that the rope is rigged with the same end at the top, so the excess
sheath bunches at the bottom. When satisfied that no further slippage
is taking place, cut off the surplus sheath and re-melt the end.
This simple procedure has no affect on the general properties of
the rope.
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. So it is unwise
to place too much reliance on the length marked. New ropes are better
in longer lengths. Later they can be cut into shorter pieces, perhaps
at a damaged section, or to provide a short (mid-rope) sample for
periodic testing.
Marking
Ropes
At a
minimum, ropes should be marked to indicate length, type (static
or dynamic) and age. It is important that this information remains
with the rope throughout it's life. On expeditions to deep cave
systems where equipment is pooled, each group should also be able
to identify it's own ropes.
There
are many different methods of marking, the main criteria being durability
and that the information is un-ambiguous and legible. Generally
such information is better written (in abbreviations) than coded.
For anyone lacking the 'key' a code is meaningless and entirely
defeats the object.
One simple
method is to bind the rope for about 5cms. from each end with a
couple of turns of PVC adhesive tape. The information is written
on this with waterproof ink, and protected by a couple of coats
of clear plastic adhesive.
This
type of marking although crude, is fairly durable and anyhow is
very easily removed from time to time. A more sophisticated version
entails first binding the ends with PVC tape, which is then marked
with strips of adhesive figures such as those used by electricians
for identifying cables, held firmly in place by transparent heat
shrink sleeving. This method seems ideal, but, in practise in muddy
regions a film of dirty water seems to creep beneath the heat-shrink
sleeve and eventually obscure the figures.
A final
minor point, whatever marking method is used, it is best not to
bind the end of a rope in such a way that either increases it's
diameter significantly or makes more than a few cms. rigid and so
prone to getting caught up in cracks, or Eco anchors on pull through
trips.
Storage
Ropes
are ideally kept in a cool, dark, well ventilated place, loosely
coiled and hung on either plastic tubes or un-treated wooden pegs
or rope loops. There is no merit in force drying a rope before storing
it. Ropes are not harmed if left to dry slowly until the next trip.
S. R. T, ropes are designed not to spin under load, but this property
leaves them with a tendency to form kinks when twisted. Given that
ropes used underground are generally fed loose into a sack and coiled
only for storage, it makes no sense to adopt a wrapping method which
twists the rope and must later be unwound as the rope is packed.
This is the case with the normal mountaineering methods of coiling
rope. A more practical method for the caver is to fold the rope
into hanks by laying loops across one hand, the finished coil secured
with a few turns of rope. It is difficult to hold more than about
40m. of rope in one hand, so a longer rope can be coiled in two
halves working from the centre outwards. The whipping is done with
the section between the coils. For a very long rope (l00m +) it
is necessary to work in stages, laying each coiled section on the
ground before continuing with the rest, Handling long lengths of
rope (60m.+), the process is made much faster and easier by wrapping
the rope around three sturdy pegs fixed to a wall. Apart from a
cellar or other dark place, to protect ropes from U/V radiation
the rack should be covered with a heavy tarpaulin. Other wise ropes
can be stored in lightproof containers such as metal or plastic
dustbins.
Anyone
un-prepared for this amount of routine maintenance is definitely
in the wrong game. A caver's life depends on his rope. Much better
to give up caving altogether than to risk killing himself by neglect
of his equipment.
Rope
Life
All this
paints a black picture and cavers might look forward to a short,
uncertain future, but in tact rope failure is rare. Even so, how
can we tell if a used rope is still safe?
There
is unfortunately no simple answer to this question, one which if
not on each cavers lips, certainly lurks somewhere at the back of
his mind. Underground a number of factors conspire to weaken the
rope. From the moment a new rope is un-reeled and hung in a pitch
it starts along a path of deterioration which leads inexorably to
the dustbin. Ropes still get weakened in spite of all the care taken
of them and sooner or later become un-safe for use.
The causes
of this weakening fall into three broad groups; some due to short
or long term chemical effects (sunlight, water, ageing), others
to physical factors (mud, internal wear, use in metal devices),
or to gross mechanical damage such as fraying against rock. Only
the latter cause is easily recognised and hence the inherent danger
of old, used copes. Rope materials, in common with everything else
on the face of the earth, deteriorate with the passing of time.
Even if the rope remains little used it gradually loses strength
over the years.
This
'ageing' process is speeded up enormously by poor storage or prolonged
exposure to sunlight.
There
are very few signs, least of all the outward appearance of a rope,
that give a reliable indication of it's properties. Truth is, there
is no practical method of' determining precisely the safe life of
a rope, dependant as this is on variations in age and usage.
A heavily
used rope showing obvious signs of surface wear, might be only a
few months old and still perfectly safe. Whereas an infrequently
used rope of excellent appearance but more than ten years old, is
quite likely to be dangerous, retaining only a fraction of it's
original strength. Nothing short of a test to destruction reveals
the true condition of a rope. Consequently rope must either be tested
periodically, discarded on the grounds of obvious damage, or scrapped
arbitrarily upon a certain age or number of hours use. As a very
rough guide, most new(ish) ropes can be used safely until the sheath
appears furry and obviously worn, and as a result begins to feel
limp and soft. When the sheath no longer effectively protects the
core beneath-throw it out. This crude assessment of course takes
no account of the weakening effects of age or internal abrasion,
we know already the appearance of a rope doesn't reveal much at
all, and some types deteriorate much faster with use than others.
With regard to age, five years is the recommended maximum, even
for a rope that has been little used and correctly stored. This
is an arbitrary and doubtless in some cases a conservative figure,
but even here, there is no guarantee that it has not been made un-safe
by other factors (shock loading for example) long before this time
is reached. A far more precise indication of a ropes condition is
gained by subjecting a short section of it to a destructive drop
test. The best advice is simply to aim for a complete replacement
of your ropes every few years. Keeping a fairly small stock of ropes
helps ensure that they earn their keep and are worn out before becoming
too old. Then either test the rope or give it to the local farmer
to fasten his gates with. Beyond this cavers have a clear choice,
they can either extend the rope's life, or their own!!
Dave
Elliot
Andy
McCarron...
andy.mccarron@yss.uk.com
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