The rumor is that wet ropes are significantly weaker. The instructions that come with the rope say that it is dangerous. Climbing magazine advises not to use a wet rope. UIAA supposedly got 3 falls instead of 7 like normal, before it broke. What are we supposed to think and do when we end up with a wet rope?
The dry treated rope was a 9.8mm Sterling Velocity dynamic rope with 28.8% elongation and is 62g/m rated for 6 UIAA falls
The non dry treated, standard rope, was Edelrid's Boa and is a 9.8mm dynamic rope with 32% elongation and is also 62g/m but is rated for 7 UIAA falls
We dropped the rope in a bucket of water and measured at 1 minute, then 4 more minutes for a total of 5 minutes and then 1 hour and 4 hours. The dry treated rope took longer to absorb water and it did only absorb 145% as opposed to 158%. We focused on % here because the rope lengths were different and the luggage scale was in lbs.
We measured the dry treated rope starting with a tight 0 kN and then pulled to 4kN which shocked me how much it stretches before the knots stop settling. The samples are too short and the knots too varied to draw any serious conclusions from this other than ropes stretch a LOT before they break.
Slow Pull Tests
We slow pulled with figure 8s on either end both types of ropes dry and wet. It did break about 15% lower and in our tests the dry treated rope broke lower than the non treated rope but that is probably just a fluke considering the variables in knot strength retention.
Our drop tests were approximately 15 feet with an 84lb dummy named Decker (so you don't have to). He isn't heavy but he is heavy enough to show if we are going to get a much higher force for the same exact tests wet vs dry. We did both the treated dry rope and the non-dry treated rope. In a more realistic fall than a UIAA 80kg at a fall factor of 1.8, we did not get results that show wet ropes are a concern when doing general climbing forces. Gym climbs as seen in our other videos are getting even less forces than these because the belayer isn't a steel post. This graph is our Dry treated drop tests.
Where does this gear fear come from? Here are links to the research we did.
Sterlings instructions that come with the ropes. "Wet or frozen ropes will be seriously weakened and may stretch more. It is best not to use a wet rope" *Sterlings website *Mountain project from 2010 with dead links inside of it *Climbing.com article *Edelrid information
Here is some nerdy stuff on the topic.
Thank you Celine Gissot and Michal Studniarek for the charts and graphs.
Behind the Scenes
This turned out to be quite a lot of work introducing slow pull and drop tests PLUS dry treated and none treated normal ropes. I didn't want to tell the world wet ropes were not a big deal if it actually was. So this was super diligent enough to conclude wet ropes in some normal use isn't showing any difference. Nylon, the chemical, does weaken when wet, but it isn't translating to real world results.
After Posting Thoughts
I thought the thumbnail was clever enough and the edit tight enough for this to be a 100k+ video. I think if it is too nerdy or too long it just doesn't get the traction a more simple break test video can get. However, some of our longer hour long film or course videos prove that longer content can be popular. The algorithm is tough to science but it's nice to have this content on the internet to let people relax if they are rapping off their climb in the rain.