rockboy
05-22-2006, 02:45 PM
Wet Ropes Decrease Performance Strength By Around 70%
The presence of water or ice in climbing ropes produces important modifications in their
performances, such as:
1. The dynamic resistance of the ropes (i.e. the number of falls held on the Dodero) decreases
enormously - down to 30% of the initial value - when they are soaked with water, be they new or
used, normal or waterproofed.
2. After soaking in water a rope becomes 4-5% longer, which can be correlated to the 5-10% increase
of the impact force at the first fall on the Dodero machine.
3. The negative effects of water on the dynamic performance of ropes are remarkable even in the case
of a brief soaking time, even after being splashed under a shower.
4. This behaviour seems to be due to the interaction of water with the structure of the nylon
macromolecule (according to literature).
5. Such behaviour lasts as long as the rope is wet, but after drying - in a cool, airy and shady place, as
recommended - the rope recovers almost completely its original dynamic performance, even after
various soaking/drying cycles.
6. Depending on the drying grade (normal or thorough), the rope can become shorter by 4% to 8%,
which seems to be correlated to the decrease by 6-12% of the impact force at the first fall on the
Dodero machine.
7. Even in the case of soaked and frozen ropes the dynamic resistance decreases, but less than in wet
ropes.
In conclusion, a used rope in good conditions, say a rope which can still hold 4-5 faIls in the UIAA
test on the Dodero machine when dry, might only hold 1 or 2 faIls when soaked after a sudden rain
fall, as often occurs in the mountains.
This may not be too much of a serious problem when climbing in a Klettergarten, where falls are
usually less dangerous and it takes little time to pull the rope down and go home. But mountaineers
must demand the maximum security from their rope, even when wet, since it might snap on a rough
edge during a fall. This risk is lower when the rope is in good conditions. The problem can be less
critical when climbing a glacier or an ice-fall, because the ropes are frozen, but even in this case the
temperature is very important: if it goes over 00C, the rope returns to be wet!
The presence of water or ice in climbing ropes produces important modifications in their
performances, such as:
1. The dynamic resistance of the ropes (i.e. the number of falls held on the Dodero) decreases
enormously - down to 30% of the initial value - when they are soaked with water, be they new or
used, normal or waterproofed.
2. After soaking in water a rope becomes 4-5% longer, which can be correlated to the 5-10% increase
of the impact force at the first fall on the Dodero machine.
3. The negative effects of water on the dynamic performance of ropes are remarkable even in the case
of a brief soaking time, even after being splashed under a shower.
4. This behaviour seems to be due to the interaction of water with the structure of the nylon
macromolecule (according to literature).
5. Such behaviour lasts as long as the rope is wet, but after drying - in a cool, airy and shady place, as
recommended - the rope recovers almost completely its original dynamic performance, even after
various soaking/drying cycles.
6. Depending on the drying grade (normal or thorough), the rope can become shorter by 4% to 8%,
which seems to be correlated to the decrease by 6-12% of the impact force at the first fall on the
Dodero machine.
7. Even in the case of soaked and frozen ropes the dynamic resistance decreases, but less than in wet
ropes.
In conclusion, a used rope in good conditions, say a rope which can still hold 4-5 faIls in the UIAA
test on the Dodero machine when dry, might only hold 1 or 2 faIls when soaked after a sudden rain
fall, as often occurs in the mountains.
This may not be too much of a serious problem when climbing in a Klettergarten, where falls are
usually less dangerous and it takes little time to pull the rope down and go home. But mountaineers
must demand the maximum security from their rope, even when wet, since it might snap on a rough
edge during a fall. This risk is lower when the rope is in good conditions. The problem can be less
critical when climbing a glacier or an ice-fall, because the ropes are frozen, but even in this case the
temperature is very important: if it goes over 00C, the rope returns to be wet!