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Overview

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Version A
(#2489)

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Technical Details

I acquired this rack from Kenneth Macke in 2018.

This Superack is 321 mm. tall, 82 mm. wide, 25 mm. thick, and weighs 881 g. The frame is made from 9.5 mm. stainless steel bent into a U, with an internal width of 38 mm. There are 4 brake bars. The top four bars are 25.4 mm. square and 73 mm. long. The bottom bar is 19 mm. in diameter and 82 mm. long. Allowing 35 mm. for the rope and 19 mm. for the spacers leaves 112 mm. for spreading the bars.

There are no markings on this rack.

Comments

Kenneth provided the following background information on this SupeRack:

A slightly used rappel rack, "SUPERACK" designed by Kyle Isenhart of Parkersburg, WV. Manufactured in 1977 as part of an order for 100 pieces by the Speleoshoppe (Ian Ellis) of Louisville, KY. This item is an extra piece, left over from the first production run. It was never sold (it does not have a logo stamp). It was used once in 1980 on a caving trip to Ellison’s Cave, Pigeon Mountain, Georgia, to descend Fantastic Pit (510 ft). A fifth bar was later added, as it was felt that a little more friction control was needed. It has been stored in a closet for the past 38 years. The grooves in the bars were machined during mfg., they are not caused by rope wear.

Size: 12.75" Long
Weight: 1 lb., 15 oz. (882 g)
Frame: 3/8" Dia. rod, 304 Stainless Steel
Bars: (4) 1" Square x 2.875" Long, 6061 Aluminum, plus (1) 3/4" Dia. round x 3.25" Long, 6061 Aluminum.
Fasteners: 3/8"-16 Locknut (Stn. Stl.) plus an aluminum cap nut (2 each)

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Version B
(#401, 1378, 2401)

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Technical Details

I acquired this rack from Jennifer Kerrigan around 1982, a second from Jack Hissong delivered to me at the 2012 NSS Convention, and a third in 2017 as part of Bob Thrun’s collection.

Version B is 323 mm. tall, 73 mm. wide, 25 mm. thick, and weighs 822 g. The frame is made from 9.5 mm. stainless steel bent into a U, with an internal width of 39 mm. There are four unfinished aluminum alloy brake bars. The bars are made from 25 mm. square bar stock and are 73 mm. long. Allowing 35 mm. for the rope and 19 mm. for the spacers gives a 149 mm. range for spreading the bars. Hex and acorn nuts secure the bars.

The top bar is stamped with a bat inside an oval and "SUPERACK." The left end of the four bars are stamped "1," "2," "3," and "4," respectively from top bar to bottom bar.

Comments

This is the original large-bar rack design based on Kyle Isenhart’s article in The Nylon Highway #1. This rack was designed for long drops. The large bars provide a larger mass for absorbing heat, and tend to run cooler that standard rack bars. He later published the results of temperature tests (The Nylon Highway #4) that showed the Superack ran about 30 to 35°C (60°F) cooler than a standard rack for moderate rappelling speeds.

The Superack only has four bars (with spacers between the top two), and has less friction capability than a standard 6-bar rack. This generated some controversy in the caving press, with both sides having some valid points to make. When used by an experienced caver, the Superack does what it was designed to do, but it is not a beginner’s rack.

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Version C
(#1377)

Front View	Rear View	Side View

Technical Details

I acquired this rack from Speleoshoppe as new old stock in 2012.

Version C is 322 mm. tall, 70 mm. wide, 26 mm. thick, and weighs 973 g. The frame is made from 9.5 mm. stainless steel bent into a U, with an internal width of 35 mm. There are six unfinished aluminum alloy brake bars. The top five bars are made from 25 mm. square bar stock and are 70 mm. long. The lowest bar is an unfinished Seaman-style bar.

The top bar is stamped with a bat inside an oval and "SUPERACK." Unlike Version B, the bars are not numbered.

Comments

Kyle Isenhart’s original design (The Nylon Highway #1) had only has four bars, and controversy in the caving press prompted Ian Ellis to add two more bars to this rack. The fifth bar was a standard SupeRack bar, and the bottom bar is Ed Seaman’s design (The Nylon Highway #9). My field testing and analyses (Design of Specialty Racks, The Nylon Highway #9) show that the fifth bar does not need to be as large as the upper bars, so I would have used a Seaman-style bar for both lower bars.

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