Tag Archives: climbing

Topology, Moore or Less

I get to teach Math 429 this semester.

This is the introductory topology course for undergraduates at Penn State – “point set topology” as the old-fashioned name would be.  I used to teach some of this material at Oxford but I have not had a chance to teach it at PSU before now.  I have about 25 students.

I decided to try a variation of a Moore method approach in this class.

So I started by showing the students the two-minute video above, which shows Steph Davis free-soloing and then BASE jumping from a Utah desert tower. Then I asked them, “Now you have watched the video, could you do that?”

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Rope solo experiment

Well, the weather has been too good not to go climbing, so I headed down to Donation yesterday afternoon.  Much to my surprise, I had the whole place to myself.

The picture (not very good) shows the rope solo system that I used.  This is my first time using the Peztl MiniTraxion for this purpose. (One advantage of having climbed a couple of walls is that one has a lot of interesting gear to play with on an occasion like this.)

Rope solo system picture

Rope solo system

Steph Davis has a good post on rope solo systems (and the follow-up comments are helpful too).  What I did was tie the climbing rope in to the anchor at its midpoint, with a figure-8 knot on a steel biner, so I had two independent anchored strands.  One strand went through the mini-traxion, which rode on a full strength chest harness (also clipped to the sit-harness by a short sling).  The other strand went through a Gri-Gri.

When climbing, the mini-traxion side was weighted to my gear bag and then fed automatically.  the Gri-Gri side I pulled rope through when convenient, and also tied off with a separate backup knot every now and again.   To transition to rappel, just open the cam on the mini-trax and rappel on the Gri-Gri.

At first I was pretty nervous trusting the system and moved very slowly and inelegantly.  But it soon became clear that it would work fine.  The pulley moves up with you and gives a good catch.   Still, I should probably have started with something a bit easier.  Things feel different when you are the only one around!

If working something steep, one should carry prusiks so as to be able to unweight the mini-trax and transition to rappel when hanging in space.  Of course, one could bring ascenders; but that seems to be taking the idea of raiding the aid box to an unnecessary extreme!