Cutting Away
December 2003
We all take cutting away for granted but just how easy will it be if you need to?

Rick Boardman tells us a few things about risers and cutaway systems, based on the confidential reports this year...
The Beginning
Back in the dark days, parachute systems were, to put it bluntly, a bit of a mess. Equipment had started out as military surplus, and jumpers literally took scissors to modify things whenever they had a bright idea! One of the first big hurdles in skydiving kit to emerge was how to get rid of a malfunctioned main before using the reserve.

Various Capewell release systems
The early popular way to release from a parachute was actually the Capewell, but this was not ideal for several reasons, mainly because you needed to put a fair effort into releasing from both left and right risers simultaneously, and you needed both hands to do it.

If you got one riser off ahead of the other, it could make the second riser release very difficult. These problems stemmed from the Capewell in its various forms being actually a device primarily for use on the ground, to prevent the jumper being dragged in high winds. The design gradually changed, and was tweaked by jumpers and manufacturer, but something radical and new was needed.
Capewells required a two-action release with both hands simultaneously
Enter Mr Booth…
In 1982, Bill Booth patented the 3-ring circus. It seems impossible today to imagine our kit without it. Compared to what went before, Bill’s simple looking assembly was a quantum leap.

From two co-ordinated simultaneous jobs with both hands, releasing the canopy now involved one downwards pull with one hand.
The design appears simple but is actually quite cunning. I’ve got a mathematical model of forces within a 3-ring, which I only read when I’m feeling masochistic! Put very plainly, each ring set acts like a set of levers. When a standard riser is loaded to 600 lbs, it should only take between 1 and 5 lbs to extract the yellow cable from the loop.

Later, driven by jumpers’ relentless desire for all things smaller and lighter, the mini 3-ring emerged. At the same time, the riser itself was reduced from a 3,600 lb Type 8 webbing to a thinner 2,500 lb Type 17. The new 3-ring system now had shorter levers, and therefore the loop was now pulled harder against the yellow cable. A 600 lb load on a mini 3-ring should mean between 2 and 6 lbs was needed to extract the cable.

What was attached to the risers was also changing fast. Newer, smaller canopies were emerging on the market, which were built with smaller lines, precision cut wings, and less forgiveness for mediocre packers.
The 3-ring system requires a single pull
Reserve Static Lines (RSLs)
Lots of fatalities over the years had been caused by people cutting away and then failing to pull the reserve, either at all, or until it was too late. Enter the RSL! A riser fitted with an RSL would pull the reserve for you.

All well and good with big risers, but modern small ZP canopies with microline and a habit of opening hard were usually fitted with those snazzy mini risers. A few risers actually failed and for the first time we referred to them as a ‘fusible link.’ It was a good job these risers had failed because, if they hadn’t, the harness would have been next. It did make a lot of people nervous about that RSL though.
Mini 3-ring with RSL
Two solutions emerged:
1 Strengthen the riser with additional tape built into the 3-ring section.

2 Reverse the whole riser, so that there is no need to have a grommet punched through the webbing.
When you look at the amount of webbing left either side of that grommet, it’s amazing how little holds you up! The latest specification for mini risers has yet another layer of tape built into the grommet area, to beef things up still more.
Original mini 3-ring (0), strengthened riser (1) & reversed riser (2)
Soft Cutaway Housings
Soft fabric cutaway housings appeared on rigs several years ago, as an alternative to metal ones.
Briefly the ‘must have’ option, these started to fall out of favour when it was realised that they had two problems:

1 The fabric housings added extra friction to the yellow cables.

2 The housings didn’t fully house the left hand cable at all. On most systems, the cable routed around the neck between the layers of the container. This made the length of that cable difficult to predict. Getting both cables to release together was not easy.

Within a few years of the soft housings peaking in popularity, there was a flurry of hard housing retrofits and today soft housings are the exception rather than the rule.
Soft cutaway housing
Riser Twists
The new canopies continue to load mini risers up towards their limits, particularly on hard openings or fast rotating mals. A more recent discovery has been the effects of riser twists on the cable channels. As the riser twists and stretches under heavy load the cables can be gripped ever tighter.

The industry solution has been to insert hard housings into the riser channels, and they do a very good job.

If you ever get a chance to see Mike Truffer’s tapes or lectures on this subject next time you’re stateside, take it.
Twisted risers can grip the
cutaway cable
A hard housing insert in the riser channel
With hard riser channels, twisted risers no longer grip the cutaway cable
Maintenance
Don’t be afraid to occasionally cut away your 3-rings and flex the webbing before carefully and correctly reassembling them. This makes the action cleaner if you ever need them in anger.

Such maintenance should be done for you on each reserve repack, so put a note on your calendar for halfway through the six month pack cycle. Consult your rigger.

Food For Thought
Quite a few safety notices exist concerning risers. Next windy day, trawl through the file at your DZ, and see how many problems have occurred. I still occasionally find punters who didn’t know they were using grounded risers.

Mini 3-rings are not easy to make. Different manufacturers ‘do it their way’. The magic secret is to make sure that, as the riser comes under high load during a malfunction, it actually stretches into the right measurements, rather than out of tolerance. If the risers are not built correctly the pull forces to get a cutaway can be massive.

3 Bloke Test
You can play with the different pull forces under ‘normal’ flight and emulating high G forces, by setting up a ‘3 bloke test’.

Get the rigger or CCI to show you how. Perfect for winter weekends!
All 3-ring systems need space in front of them, for the rings to pivot and flick through each other. If something gets in their way, like my head in the photo, nothing much happens... scary, ain’t it?
Severely twisted risers could potentially jam your cutaway system
And Finally
A low experienced jumper recently found himself under a main and reserve. The system had reversed risers. As the canopies started to separate, threatening to downplane, the jumper elected to cut away. He pulled the cutaway pad more slowly than normal and, as the main canopy released on one side first, it trailed behind him by the remaining riser. Being a reversed riser, even though the second cable extracted a second later, the rings were prevented from pivoting through by the shoulder of the jumper.

Luckily, the jumper completed the descent without the semi-collapsed main fouling the reserve... Phew!
Reversed riser jam
Article & photos by Rick Boardman
RicksRiggery@aol.com

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