Wet ropes

[robsantos]

Hi everybody !

Does anybody knows how long can a static rope (11mm PMI and New England) can stay in wet conditions inside a cave? No tensile strength is being applied, and obviously it is 100% dark conditions.

Thanks,

rob santos

[cob]

Uhhh..... Forever?

(sorry, I couldn't pass on the smart ass response)

tom

[robsantos]

Ok sorry, maybe the right question should be... When the rope is dried, will it lose strength ?

[Phil Winkler]

I can't imagine those conditions affecting the rope on bit.

[paul]

Not a definitive answer but interesting:

Have a look at "The strange story of orpheus rope number 10" on http://www.orpheuscavingclub.co.uk/newsletters/vol38_num12.html

[Scott McCrea]

Wet nylon does lose some percentage of its strength, but it is regained when the rope dries. I can't remember the exact numbers, but they are available on the internet and probably earlier in this forum.

Quality caving rope is very durable. Of course, each situation will be different, but generally, just leaving a rope in a cave shouldn't hurt it too badly. However, leaving it hanging in a waterfall could expose it to abrasion. Then there is always the chance that a critter will chew on it. Always check a rope before using it.

In ideal conditions, rope will last for a long time--years. Storing rope in a cave is probably safer than in your car/truck or basement.

[stephen]

Are there any benefits or drawbacks to using a PMI E-Z Bend Sport Static rope (7/16 11mm) versus a BlueWater II Plus Static rope (also 7/16 11mm) as the primary line for SRT cave descent?

[NZcaver]

Are there any benefits or drawbacks to using a PMI E-Z Bend Sport Static rope (7/16 11mm) versus a BlueWater II Plus Static rope (also 7/16 11mm) as the primary line for SRT cave descent?

Check out http://www.caves.org/phpBB2/viewtopic.php?t=956

[stephen]

Thanks. The analysis addressed PMI "Classic", PMI "Pit", and PMI "Max." Is there any reason not to use a PMI E-Z Bend as the principal rope for a 150 ft drop?

[Tim White]

Thanks. The analysis addressed PMI "Classic", PMI "Pit", and PMI "Max." Is there any reason not to use a PMI E-Z Bend as the principal rope for a 150 ft drop?

No reason at all not to use E-Z bend. It is basically Maxi-Wear with a looser woven sheath which makes for a softer “handâ€

[stephen]

Thank you!

[Scott McCrea]

Just don't forget, looser sheath means less abrasion resistance. It's a trade off--softer hand vs abrasion resistance. Different drops/situations may be better for one or the other type of rope. You should really have miles of both.

[Tim White]

...You should really have miles of both.

[wyandottecaver]

one example of which I am sure there are others... In the early 70's a 100' piece of 11mm bluewater was rigged to access an upper stream passage. It was left hanging into a pit ledge where the bottom end was tied off. While not in an active waterfall, it did probably see water during heavy rain events.

in 2002 it was replaced and subsequently strength tested in a lab setting. Despite hanging in a intermittently wet pit for 30 odd yrs it still retained 2/3rds of its "new" breaking strength.

[ek]

Wet nylon does lose some percentage of its strength, but it is regained when the rope dries.

Does it lose its tensile *strength*, or does it lose its *elasticity* (thereby causing higher forces to be generated when there is a shockload)? I have always seen people talking about a reduction in the number of falls a rope can withstand when wet, and never hard numbers specifying dry and wet tensile strengths.