Recently a caving companion decided to build a Frog system. Here is some Q&A that may be useful for others. Read the article by Matt Oliphant first.

Do you use a neck loop or a chest sling on your system?

For 15 years, I used an elastic loop over my arms and crossed in the back, like a bra. In 2000, I tried a GGG chest harness designed specifically for the Frog. I wish I had done this a long time ago. The harness holds the Croll firmly, so there is much less wasted motion of taking up slack. My back is much better supported when resting or hauling a load.

20-2002R GGG Frog Chest harness. Drawing courtesy of GGG/IMO http://www.caves.org/imo/harness.htm

The problem with a neck loop only is comfort. For a few more ounces and dollars you can have a proper harness that goes to your seat harness (see illustration). This distributes the load from the Croll instead of putting it around your neck.

Do you use a normal seat/sit harness or a swami?

The seat harness is critical to positioning the Croll. It must hold the Maillon low and flat, and not let it move around a lot (wastes climbing motion).

How do you rig the loops from the handled ascender to the foot loops?

I use a stainless maillon connected to tied SuperTape, with a single loop to stand in. The loop has vinyl tubing to protect the center section (about two feet) where I stand. I will switch to Spectra cord at next maintenance.

One of the great things about the Frog is that it requires almost no sewing. Everything except the chest harness can be tied. (Some vendors do sell sewn parts, however.) Tape the knots and check them regularly in mud and water, especially when new!

I've got a Croll and a Jumar but it looks like a Handled Jammer or Clog might be better (more room in handle for double hand grip).

A Jumar would do as top ascender for testing and deciding if you want to use a Frog. Then get a Jammer: smaller, better shape, grips better on muddy rope.

What is your opinion on using two foot loops as opposed to one large loop?

I like one large loop. Advantages and disadvantages:

easy step-in, great for standing in mud or water

quickly pull out one foot to push off walls, lips, etc.

use one foot to help get the other in when climbing; very seldom need to use hands

rope can be run between the feet for self-starting (this can also be done with two small loops, as shown in Matt's article)

separate loops let you spread legs independently which is good for balance in some situations

Nathan Noble's frog rig after a deep trip. The MicroRack is connected full-time to the seat maillon; no carabiner to loosen. The foot loop is wrapped around the jammer and attached to the carabiner at right. Note that the cowstails should be on the other side of the Croll. The whole system is ready for use, yet the caver can walk, crawl, and squeeze without removing any gear. (Photo by J. Ganter)

Version 1, 12 October 2000