Mar-bar

Vertical caving terminology and methods > Personal SRT gear

Mar-bar, Mars bar

View image
A home made mar-bar made using angle aluminium, following the instructions published in Nylon Highway No. 5 1976. The ascender is a 1975 handled Clog with a thin frame, so angle brackets were made to hold it perpendicular to the mar-bar. The mar-bar is bolted to the ascender using a horseshoe bolt. It was made using only the tools that a typical caver might have had at the time.
View image
Mar-bar in its usual position, as part of an inchworm system rig.

An essential part of the inchworm system, which attaches a handled foot jammer to the feet. The foot jammer is bolted, screwed or tied to the middle of a metal or wooden bar, or webbing tape covered in a plastic tube, wide enough to put both feet on it, so that the foot jammer sits between the feet. A strap or rope then runs from one end of the bar, through the metal loop at the top of the ascender, and down to the other end of the bar, passing over both feet. This is what causes the foot jammer to be lifted when the feet are raised. The foot jammer must have a single metal loop at the top, on one side of the frame only. If the strap has to pass through holes on both sides of the frame, it will not be possible to get the main rope in or out. Mar-bars were almost always custom made by the person who would end up using them, so there is a great deal of variation, and no standard approach for how to connect them to the ascender. Most designs rely on the square chunky frame of a Jumar brand ascender, which also had a single loop at the top. The name is a shortened version of "Jumar-bar", and comes from the USA, but there seems not to be a British alternative.

|

This page is not intended to be viewed this way, please load the . This version exists only to make it easier for search engines to understand the contents.