Aerial Rigging: Carabiners/Quick Links/Shackles?

Early in my aerial training one of my instructors asked me to “check a carabiner.” Sure, no problem. Look at it. Check! Make sure it’s locked. Check! Easy peasy! Now I try to make a habit of checking biners whenever I go up on equipment. Yes, I have found a few carabiners that were not locked, carabiners that were cross loaded, carabiners that are overloaded and carabiners that are stuck closed/open or damaged. As an aerial student it’s important to ask questions and learn about the equipment you are using.

As I was writing this blog, I found these videos from Vertical Art Dance. Please take a few minutes to watch them. I learned I was currently making rigging mistakes. I’m heading back to make some new purchases and update my hardware. I need to stop relying so much on carabiners and think about using Quick Links and shackles more often.

Aerial Rigging The Carabiner Talk Part 1

Aerial Rigging The Carabiner Talk Part 2, Overloaded Carabiners
*I have been overloading my spansets for my lyra into carabiners.

Aerial Rigging: The Carabiner Talk Part 3, 3 Way Loading
*I have been 3-way loading my lyra spansets onto one carabiner. I knew it wasn’t ideal but I didn’t know it was a bad mistake.

Why is this important? Remember the Ringling Hair Chandelier accident? It was due to an improperly loaded connector. Review the article and some of the comments. Then look around at what is being used at your studio or your own set up and ask questions. Is it safe? Is there a better way to rig it? Why did they/you decide to rig that way?

Here are some tips about connectors for aerial rigging:

CARABINERS

• Before use, carabiners (and all connectors) should be inspected. Damaged or worn carabiners/connectors should NOT be used. Visually check for any stress. Look for bending, corrosion, excessive wear, or cracking. The locking mechanisms should have smooth operation. If it doesn’t take it out of service and don’t use it.
• Carabiners need to be oiled (& cleaned) regularly. Sometimes locking biners stop working just because they haven’t been oiled.
• Screw down, so you don’t screw up! It may not be a huge deal in aerial, especially if you are using auto lock biners, but it can help keep screw gate carabiners locked if there is anything that might rub on the screw gate and unlock it. Examples: a hand grabbing the biner, a knee locking around it, a rope/spanset rubbing against it, or even vibrations loosening the the screw. This video explains in a bit better. Not much of an issue with auto lock biners but its not a bad habit to get into for all biners just in case. *If you don’t know the difference between a screw gate and an auto lock carabiner please watch the above videos again and read the Simply Circus link below.

Carabiners are designed to take a load only along the major axis:

• Do not cross-load a carabiner. Loads should only be placed lengthwise along the major axis. If a carabiner is loaded widthwise it could fail especially with a drop or abrupt change in motion. They are a lot less strong widthwise (up to 70% less).
• Do not overload a carabiner. Review Video Part 2 again. Spansets can easily overload a carabiner. Rigging a silk directly to a carabiner will also overload it.
  

  Double-point Lyra rigging with rigging plate: Carabiners are overloaded with spanset

  

  Double-point Lyra rigging: Carabiners overloaded with spanset

  

  Mistake in rigging: double-point Lyra rigging: tri-loaded and overloaded carabiners
• Do not 3-way load a carabiner. Review Video Part 3 again. I’ve seen this a lot in rigging. So much that I thought it was normal. But its not. It is a mistake in rigging. See above pictures of rigging a double-point Lyra. Have you rigged this way? Which way is the best?
  Riggers have been lucky only because they use a large safety ratings (2000-5000 lbs). It is a better idea to use hardware that is designed for 3-way loads (an anchor shackel or a Quick Link).
  This is an interesting video that shows testing tri-loading carabiners. Its focus is on slacklining, not aerial, but its still good info.
• The D-shaped carabiners are usually stronger than the oval carabiners…but only if the load is verticle down the long end of the carabiner. *I’m re-thinking how to rig the pulley on my outdoor rig I was going to use a 50kN steel D-shaped biner at the top but now I might look for a Quick Link or shackle so its not overloaded.
  

Please read this reference on carabiners from Simply Circus: Carabiners.

There are tons of places to buy carabiners. I’ve purchase mine from Aerial Essentials and Fusion Climbing. I like the sleek black coatings that they offer. They are more expensive than the regular stainless steel biners.

*I’ve been buying steel (vs aluminum) carabiners because I believe they will last longer than aluminum. I am planning to write a blog about that debate.

SHACKLES

I have heard/read that many professional riggers are recommending using shackles instead of carabiners. Especially if it is a permanent connection. Carabiners are designed for quick/temporary connection.

• Shackles are a lot stronger than carabiners
• 2 main types of shackles: Anchor/Bow shackle can connect 2 or more rigging pieces together while a Chain/”D” shackle is designed to connect components in a straight line. See the Simply Circus link below for more info and pictures.
• Shackles will decrease the amount of height lost when using a carabiner (average shackle is 3″ vs 5″ carabiner).
• For aerial you can use a screw pin shackle that can be moused/locked in place with a zip tie after they are screwed tight. (You could also use metal wire to mouse it.)
• UPDATE: Load only in one direction on the pin of a shackle. Use the bell to collect the legs of a bridal. (In other words: when 3-way loading, put 2 loads on the bell and 1 load on the pin.)
• My fiance calls them “bull nose” As in: “Amy, why are you using carabiners when you should just get a bull nose? They are safer for you.” (I had no idea what he was talking about. Until now)

Please read this reference on shackles from Simply Circus: Shackles. This link has a ton of information with pictures of different shackles, how to inspect & clean and even how to mouse a shackle.

You can buy shackles MANY places. This is an example of all the different types at Rigging Warehouse.

QUICK LINKS

I’m just learning about Quick Links (or screw links). I didn’t even know what they were up until about a month ago.

• Quick Links come in several different shapes. Depending on your need, you may want to use a triangle/tri-link/delta/square Quick Link to attach spansets to a swivel for a double point lyra (instead of 2 carabiners into a swivel-see Part 3 video above)
• To avoid overloading a carabiner with a spanset, consider using a Quick Link (again I refer back to the videos above). Review the Quick Link shapes to see which may be the best fit.
  Update: Delta and tri-link Quick Links are for vertical use only. They are wider to be used with webbing.
• Link to Petzl Maillion Rapide technical info
• Ratings are significantly lower when cross-loaded. (Ex. a Quick Link that is rated 25kN on major axis can be rated 10kN on minor axis)
• When tightened with a wrench Quick Links can be considered a permanent connector.

I am attaching several links that have more Quick Link information:

Aspiring Safety Products:  This has Quick Link ratings and a description of why and what they use particular shapes.

You can buy Quick Links at MANY places. This is an example of all the different types at Rigging Warehouse. I’ve read that many people recommend Maillion Rapide Quick Links because they have very good reliability.

I’d love to hear your thoughts on connector use and aerial rigging?

*Interesting solutions to “fix” tri-loading carabiners and spansets (or Quick Links) from a slackline point of view. Remember to consider the ratings on the spansets when putting them into different shapes: basket, chocker, etc.  Triloading 101