Version A	Version B	Version C

Overview

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History

Let’s consider a “type of assembly in which an individual can lower himself downwardly along a rope.”

"Assemblies of this general type are known, in mountain climbing, for example, it is essential with the conventional assemblies of this type that the operator manually engage the structure for stopping the lowering of the load at a selected elevation along the rope. Thus, it is essential that an individual who is being lowered downwardly along such a rope have at least one hand free in order to manipulate the structure for terminating the lowering at a selected elevation. Since the individual who is being lowered will release the structure to permit it to move downwardly along the rope, there is practically no control on the speed of movement downwardly along the rope."

Thoughts like these that recognized the sad state of affairs in descender technology led Ronald Foote to invent and patent the Descent Master. His patent application of March 10, 1966 predated racks, stop bobbins, and a wide variety of more recent ideas of varying merit, so perhaps we should forgive his concurrent unfamiliarity with future innovations. Atlas Safety Equipment Co. Inc. of Matawan, N.J. soon put it into production, christening it the Descent Master.

The Descent-Master is made from two pieces of cast aluminum (a braking plate and a pivoting control handle), a commercial snap hook, and some minor parts. The braking plate has a carabiner-like opening at the top that is used much like a carabiner-wrap rappel. Always wrap a dextral helix! A post cast on the inside of the brake plate guides the rope, and creates drag by pressing a concave area against the rope when the control arm is in the upper ("stop") position.

The control handle is hinged to the bottom of the braking plate. Two wire springs act to raise the arm, although the action is weak. There are four posts on the inside of the control arm. Each one has a slot on the side to act as a rope guide. The bottom post is larger and has a flat surface that presses against the rope when the control arm is raised to the "stop" position.

A snap hook attached to an eye on the back of the braking plate clips to the user’s harness.

I learned of the Descent Master from the first edition “Rappelling” (Tom Martin 1985) after he visited my apartment to photograph gear for his expanded second edition (1987). He warned, “Because Descent-Masters have been known to break during a rappel, they should be used with extreme caution.” Some people might see this propensity to provide uncontrolled full gravitational acceleration as suboptimal, but I was intrigued. Surely this would make a good loaner descender to share with speleo-politicians.

I acquired my first Descent Master in 2004, and the Vertical Museum now has three versions, all different. The second version added a thin wire safety to the distal post on the control handle. Although paper-clip thin, it is more effective than the Hiebler Ascender safety. My third version is somewhat beefier than Version A, but not finished as nicely. The hinge area between the back plate and control handle is significantly stronger than in Version A. Much of the surface is a rough, sand-cast finish.

The Descent-Master is easy to operate - just pull the handle down to descend and move it upward to slow down or stop. The Descent-Master is designed to stop if the user lets go of the handle. I don't recommend testing this feature.

My Descent-Masters don't give me a smooth descent. The wrap at the top of the Descent-Master puts a twist on the rope and kinking is a problem. The device is also somewhat sensitive to rope diameter. Atlas used to insist that the descender must be returned to the factory if the rope wore out so that a new rope could be custom-fitted. Whether this reflected reality, a commercial ploy to sell only their own rope, or the mutterings of the company lawyer is beyond my knowledge.

Early Descent Masters came with their own special rope. We looked at this rope the day before Groundhog Day, and noted that it was one of the stiffest rappelling ropes ever made specifically for that purpose. Maybe the steel core had something to do with that. Anyhow, rigging the Descent Master with this rope is challenging. Atlas soon recognized that Descent Masters don’t like stiff rope and will jam to show their annoyance. Later versions used thin, limp, loose woven nylon and dropped the steel core.

My Version A (made in September 1970) was serial number 236, Version B (made in October 1977) is serial number 312, and Version C (made in October 1984) is serial number 723. If the serial numbers are consecutive and not restarted at times, this would indicate that few Descent Masters were made and sold.

A Special 9.7 mm. Static Rope

I do not try to collect different rappelling ropes, but I have acquired a few over the past 50 years. This is a sample of an early static rappelling rope sold in March, 1970, but there is good reason to believe that this rope dates back to 1967 or even earlier. Think about this a minute. This is a 9.7 mm. rope made specifically for rappelling in the 1960s, a time when most cavers in the USA were using either 11 mm. mountain-lay Goldline, a stiff laid rope, or 11 mm. Samson 2-in-1 braid-on-braid, one of the softest, limpest ropes that I’ve ever used. BlueWater had not introduced their kernmantle caving ropes. PMI rope was in the distant future. The thin ropes craze was till decades away. This 9.7 mm. rope was available... and almost nobody used it. Why?

First, let me say, that this is a quality rope, and one that I would not be afraid to use today. While it does not have any CE approvals, those standards didn't exist back then and I’m in the USA where they don’t matter anyhow. This rope was strong enough out-of-the-box, and I seriously doubt that it has lost any significant strength in the past half-century. It is extremely static, with less stretch than most later kernmantle static ropes. Its abrasion resistance before failure is excellent, and I cannot think of a modern caving or climbing rope that could match its cut resistance. While it is a stiff rope, it is not unreasonably so. It isn’t too hard to tie knots in, although untying a knot after loading can be difficult. One down side, it does tend to kink.

Why didn’t it become popular? I can only guess. The rope was only sold with a descender that really wasn’t suited for caving. I can discuss the descender at another time, but some viewed the descender’s tendency to occasionally self-destruct, releasing the rappeller to earth’s nominal 9.8 m2/s acceleration and exposing them to the inevitable upcoming multi-g deceleration, as a negative feature.

Why does this rope have such special characteristics? After all, the mantle is a fairly normal sheath consisting of 32 nylon strands braided with eight clockwise and eight counter-clockwise pairs. Nothing unusual there. The core is less traditional by todays standards, consisting of a 3.5 mm. steel cable with a 5.4 mm. rubber sheath – and that makes this rope special.

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Version A
(#913)

Front View	Rear View
Left Side View	Right Side View

Technical Details

I acquired this Descent Master from Ann Dunn in 2002. It was manufactured on September 28, 1970.

The Descent-Master is made from two pieces of cast aluminum (a braking plate and a pivoting control handle), a commercial snap hook, and some minor parts. The braking plate is 178 mm. high, 12.7 mm. thick, and 49.5 mm. wide at the base (the top end is only 45.2 mm. wide). One end has a 63 mm. tall, 19.5 mm. wide slot. One side is cut out to provide a place for a cast aluminum gate. A 3.3 mm. steel (not stainless) rivet holds the gate in place. A wire spring wrapped around the rivet closes the gate. The maximum gate opening is about 13 mm. There is a post cast on the inside of the brake plate that serves two functions. First, a slot in the post guides the rope, which should be wrapped around the brake plate to the right of the slot in a right-hand helix. Tom Martin (Rappelling, 1985, p. 6-34) reports that one wrap should be used for 32-158 kg loads, and two turns for 159-181 kg. The post’s second function is to create drag by pressing a concave area against the rope when the control arm is in the upper ("stop") position. Finally, an eye on the bottom outside surface of the braking plate provides a place to attach a type 3047A snap hook with a standard 5/16-inch chain connector. The bottom of the braking plate has two cutouts to mount the control handle.

The bottom end of the control handle has two prongs that curve inward to fit into the slots at the base of the braking plate. A 4.4 mm. steel pin serves as a pivot, and two wire springs wrapped around the pivot act to raise the arm (although the action is weak - the springs will only raise the arm about 45° above the horizontal. The control handle is 204 mm. long, the bottom 40% is 35.3 mm. wide and 13.8 mm. thick, while the top 60% is 27 mm. wide and tapers to only 8 mm. thick. There are four posts on the inside of the control arm. Each one has a slot on the side to act as a rope guide. The bottom post is larger and has a flat surface that presses against the rope when the control arm is raised to the "stop" position.

There is a sticker on the outside of the control arm that reads as follows (I used red text to indicate stamped information):

Date 9-28-70 CAUTION SERIAL NO 236

1. WRAP ROPE ON SLIDER LOCK 2. INSERT ROPE IN ALL GATES ON DEVICE 3. SECURE ROPE TO STATIONARY
OBJECT 4. ATTACH DEVICE TO SAFETY BELT WITH snap hook 5. PULL TO DESCEND - RELEASE TO STOP.
DESCENT MASTER PATENT NO. 3357520

ATLAS SAFETY EQUIPMENT CO. INC.
179 N. 10th STREET, BROOKLYN, NEW YORK 11211

The snap hook has the normal U. S. Forgecraft markings: "3047A Fc TESTED." The chain connector is marked "BTC" and "5/16" on each side.

My Descent-Master came with it’s own very stiff 9.7 mm. kernmantle rope. The rope is so stiff that getting the rope in and out of the slots is difficult since the rope resists flattening. Tom Martin (Rappelling, 1985, p. 6-34) claims that old Descent-Master rope had a steel core, and that later ones used 11 mm. rope. The rope that came with mine has a 3.5 mm. steel core, then a rubber sheath that brings the diameter to 5.4 mm., then a 32-strand (eight pairs each way) nylon mantle that brings the final diameter to 9.7 mm.

Comments

First of all, I’d like to thank Adam Noble for finding this Descent-Master on eBay.com and letting me know about it. I had been looking for one since 1985 when I first saw a picture of one in Tom Martin’s book Rappelling. Needless to say, I was surprised to find one after so many years.

The Descent-Master is easy to operate - just pull the handle down to descend and move it upward to slow down or stop. The Descent-Master is designed to stop if the user lets go of the handle. I don't recommend this - I have my own my thoughts on rappel safeties.

The Descent-Master doesn't give me a smooth descent. The wrap at the top of the Descent-Master puts a twist on the rope and kinking is a problem. The device is also somewhat sensitive to rope diameter. The manufacturer used to insist that the descender must be returned to the factory if the rope wore out so that a new rope could be custom-fitted. Whether this reflected reality, a commercial ploy to sell only their own rope, or the mutterings of the company lawyer is beyond my knowledge.

This Descent-Master is one of the early models. Tom Martin (Rappelling, 1985, p. 6-36) claims that earlier models could be controlled from the ground, but neither the text nor the photos in his book explain how this was done. Don't try it. He reports that this feature was deleted from later models.

The Atlas Descent-Master is protected by U.S. Patent 3,357,520.

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Version B
(#1227)

Front View	Rear View
Left Side View	Right Side View

Technical Details

I acquired my Atlas Descent-Master, Version B from Gary Lubra in 2009. It was manufactured in October 1977.

Version B is 206 mm. tall, 50 mm. wide, 92 mm. thick, and weighs 807 g. Version B is similar to Version A, although there are minor differences in the casting, the main one being the visible steps in the posts on the braking plate. These seem to be cope & drag parting lines in the sand casting. The main functional improvement in Version B is the addition of a 2 mm. wire safety pin attached to the braking plate with a jack chain and machine screw.

There is a sticker on the outside of the control arm that reads as follows (I used red text to indicate stamped information):

Date 10-77 CAUTION Serial No. 312

1. Use only rope supplied with the unit 2. At least one turn on slider lock is
essential 3. Insert rope in all gates on device 4. Secure rope to stationary
object 5. Attach device to safety belt with snap hook 6. Pull to descend
7. Release to stop
Descent Master Pat No. 3357520

There is a second sticker on the inside of the back plate. It reads as follows:

CAUTION
1 - AT LEAST
ONE TURN ON SLIDER LOCK
IS
ESSENTIAL
2 - TO STOP
RELEASE HANDLE

The snap hook is stamped "ATLAS" and "403-A." The chain connector is marked "BTC" and "5/16" on each side.

Comments

The Descent-Master is easy to operate - just pull the handle down to descend and move it upward to slow down or stop. The Descent-Master is designed to stop if the user lets go of the handle. I don't recommend this - I have my own my thoughts on rappel safeties.

The Descent-Master doesn't give me a smooth descent. The wrap at the top of the Descent-Master puts a twist on the rope and kinking is a problem. The device is also somewhat sensitive to rope diameter. The manufacturer used to insist that the descender must be returned to the factory if the rope wore out so that a new rope could be custom-fitted. Whether this reflected reality, a commercial ploy to sell only their own rope, or the mutterings of the company lawyer is beyond my knowledge.

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[ Top | Version A | Version B | Return to Misc. Descenders ]

Version C
(#960)

Front View	Rear View
Left Side View	Right Side View

Technical Details

I acquired this Descent Master from John Klewicki in 2004. It was manufactured in October 1984.

The Descent-Master is made from two pieces of cast aluminum (a braking plate and a pivoting control handle), a commercial snap hook, and some minor parts. The braking plate is 181 mm. high, 13 mm. thick (20.5 at the axle), and 52 mm. wide (at the base, the top end is only 46.5 mm. wide). One end has a 63 mm. tall, 18 to 19.5 mm. wide slot. One side is cut out to provide a place for a cast aluminum gate. A 3.3 mm. steel (not stainless) rivet holds the gate in place. A wire spring wrapped around the rivet closes the gate. The maximum gate opening is about 13 mm. There is a post cast on the inside of the brake plate that serves the same functions as in Version A. Finally, an eye on the bottom outside surface of the braking plate provides a place to attach an Atlas type 403-A (U. S. Forgecraft type 3031) snap hook with an 8 mm. maillon. The bottom of the braking plate has two cutouts to mount the control handle.

The bottom end of the control handle has two prongs that curve inward to fit into the slots at the base of the braking plate. A 5 mm steel pin serves as a pivot, and two wire springs wrapped around the pivot act to raise the arm (although the action is weak - the springs will only raise the arm about 30° above the horizontal. The control handle is 210 mm. long, the bottom 40% is 35.8 mm. wide and 14.2 mm. thick, while the top 60% is 31.5 mm. wide and tapers to only 7.5 mm. thick. There are four posts on the inside of the control arm. Each one has a slot on the side to act as a rope guide. The bottom post is larger and has a flat surface that presses against the rope when the control arm is raised to the "stop" position. The top gate has holes that allow inserting a 2 mm. wire safety. The safety is attached to the braking plate with a short jack chain.

There is a sticker on the outside of the control arm that reads as follows (I used red text to indicate stamped information):

Date 10-84 CAUTION Serial No. 723

1.Use only rope supplied with the unit 2. At least one turn on slider lock is
essential 3. Insert rope in all gates on device 4. Secure rope to stationary
object 5. Attach device to safety belt with snap hook 6. Pull to descend
7. Release to stop
ATLAS SAFETY EQUIPMENT CO. INC.
1 JOHNSON AVENUE, MATAWAN, N.J. 07747
Descent Master Pat No. 3357520

There is a second sticker on the inside of the back plate. It reads as follows:

CAUTION
1 - AT LEAST
ONE TURN ON SLIDER LOCK
IS
ESSENTIAL
2 - TO STOP
RELEASE HANDLE

The snap hook has "ATLAS 403-A" stamped in the gate and normal U. S. Forgecraft markings "30431 Fc 84" stamped on the body. The maillon has no markings.

Comments

Version C is somewhat beefier than Version A, but not finished as nicely. The hinge area between the back plate and control handle is significantly stronger than in Version A. Much of the surface is a rough, sand-cast finish. The wire safety is rather flimsy-looking, but probably adequate.

I note that Version A (made in September 1970) was serial number 236, Version B (made in October 1977) is serial number 312, and Version C (made in October 1984) is serial number 723. If the serial numbers are consecutive (as they appear to be), this would indicate that few Descent Masters were made and sold. Of course, they could have restarted the numbering at any time.

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[ Top | Version A | Version B | Version C ]