Whip it good! - Middle Marks
In light of the increasing number of rappelling accidents, I'd been thinking about posting on the subject of middle marks. Plenty of debate over knotted ends, not so much about middle marks. Then, the other week while preparing to rap, neither me or my partner were able to find the middle of the rope... the middle mark had come out.
I consider myself to have a high standard for safety. Shame on me for letting that standard slip. That’s was the impetus behind finally getting to this post.
I’ve been climbing on one of my ropes for about 5 years. It’s a 9.8 / 70m rope which came from the manufacturer with two black ink stripes that mark the middle. Over the life of the rope I’ve replaced the middle mark twice. The first time the mark faded, I nearly purchased a rope marker, but not before realizing that the brand of rope I owned wasn’t featured along with the other brands mentioned on the package. I reached out to the manufacturer to find out what marker they recommended. “We don’t recommend using a rope marker.” Without having control over how much ink is absorbed into the rope, or the marker recipe, they couldn’t endorse any brand of rope marker in good faith. The solution they did offer was an “old school whipping knot” tied with a length of thread or dental floss at the middle of the rope. Some interwebs research revealed step by step instructions on how to go about marking the middle with some thread.
Feeling somewhat skeptical, the recommended method turned out to be long lasting with a few advantages over factory marks. A contrasting thread can offer better visibility in low light. Also, you can feel the middle mark in your hand. If you happen to lop off the ends of your rope due to damage, a new thread can be whipped at the true center of the rope. To me that's a clear advantage over rope marker or the pattern transition on a bi-pattern rope, the two types of commonly used factory middle marks.
Note: To prevent the knot from sliding up or down the rope, it is important to pass the thread through the sheath with a dull needle before starting. Do not put the needle through the core of the rope and do not use a needle with a sharp tip that could cut the fibers!!! Doing so may compromise the integrity of the rope.
Starting the thread through the sheath to keep the knot in place.
You can barely make out the factory marks where the thread is whipped through the rope below. The first time I used un-waxed nylon dental floss. The middle mark in the images below is tied with bonded nylon thread, ready for a few more years of service!
If you feel unsure about locating the middle of a rope on descent, take the extra time to pull up both ends and lower them together.
I hope you found this helpful. If you have any questions about your rope specifically, get in touch with the manufacturer. They will probably be more than happy to provide answers.
Check your knot, knot your ends and buddy check!