Originally posted 2018-03-07 23:55:11.
How To Set Up Sidemount Loop Bungees
by Andy Davis
I’ve found that sidemount Loop Bungees are the most popular with my students and offer the most refined cylinder trim, along with the easiest cylinder don/doff routine. This option is getting increasingly more popular in the sidemount community, especially with those diving ‘Mexican Cave’ style systems. However, some divers find the configuration and setup to be confusing… it’s actually pretty simple.
Here is my illustrated guide on how to set-up and size loop bungees for sidemount.
You need to add three pieces of hardware to your harness:
- A retainer on the rear spine strap from which your bungees will originate.
- Two attachment points on the front shoulder straps.
You will also need approximately 2 meters of sidemount bungee. 6mm bungee works best for most divers. However, if you are using very heavy/high capacity steel cylinders, you may want to increase the bungee size to 8mm or even 10mm in extreme cases.
These need to be set, front and back, at a height just immediately below your armpit.
The Rear Attachment
My personal preference for a rear loop bungee attachment is a custom piece of hardware. It’s basically an extended webbing tri-glide with four holes for the bungee to thread through. These are sold by several specialist sidemount manufacturers. I got mine from Andrew Goring at SUMPUK.
Once the tri-glide is correctly positioned on your spine webbing strap, it’s a simple task to thread the bungee through the holes and secure each end with a basic overhand knot.
If you don’t want to source custom hardware, you can use regular tri-glides; as sold by just about any scuba diving shop. With these you thread the bungee between the webbing and the tri-glide. You’ll probably need two tri-glides, otherwise it’ll get too crowded. Both are setup as shown in the diagram below.
The top tri-glide secures the top end of the bungee for both left and right sides. The bottom tri-glide secures the bottom bungees, both left and right sides. Again secure the ends with a knot.
The Front Attachment
There are two options that I use for the front bungee attachment on the shoulder straps. You can either elect for a fixed, or a sliding loop bungee arrangement.
The fixed loop bungee is most common. This requires more initial adjustment, but keeps the cylinder valves exactly where you want them throughout the dive.
In contrast, a sliding (or floating) loop bungee arrangement allows the front attachment to move up or down the shoulder webbing as you need it. I prefer this for my sidemount rigs that I use for very confined areas and passing tight restrictions in wrecks. Having some flexibility to move the attachments down empowers more capacity to squeeze and wriggle through small spaces.
Fixed Loop Bungee
A Fixed Loop Bungee front attachment is simply a basic tri-glide with a small, knotted, loop of 550 cord threaded between the tri-glide and the webbing. The loop bungee passes through this loop of 550 cord.
You can buy 550 cord (parachute cord) at most camping, climbing or military surplus type shops. It’s also commonly available on Amazon and eBay. This cord is also optimum for your lower cylinder leash, and if you put a leash around the sidemount cylinder valve for security.
Whilst the diagram above exaggerates the size of the loop, it’s actually much better to keep the loop as small as practically possible. The prevents your valves dropping at all, or the cylinder moving too far behind or above you as you maneuver. See the photo below:
Sliding Loop Bungee
The sliding loop bungee is my personal preference. Many divers make these by simply tying a loop of 550 cord around the shoulder harness and threading the bungee through it. I find that slides too much.
What I use is are large rubber o-rings. I got the idea from XDeep; who use those same o-rings as sliding D-rings on their waist harnesses.
Using a rubber o-ring adds slightly more friction and reduces the tendency for the attachment to always slide down to the bottom. It stays put where you want it; unless you deliberately move it.
Simply thread an o-ring onto each shoulder harness strap. Run the bungee through that o-ring.
The photo below illustrates the o-rings used. They are 50 x 8mm (metric) or 2″ x 0.3″ (imperial). You can buy these at any good plumbing supplies store; plus some specialist sidemount retailers also sell them.
Here is a picture of the o-ring bungee retainer in place on a sidemount rig:
Sizing Loop Bungees
Getting the basic sizing for loop bungees is relatively simple.
Firstly, remember to account for your exposure protection. If possible, do the sizing and adjusting wearing the exposure protection (wetsuit/drysuit) that you’ll be using.
You want the bungees to be relaxed – without tension, but not hanging too loose, from the front attachment.
Then you can test the fitting. Simply insert your thumbs into the upper strand of the bungees. Pull the bungees across the front of your chest.
They should reach your nipples under moderate tension:
They should meet together at your sternum under maximal/complete tension. This should require some effort to stretch them.
Once you’ve got them sized so that they work for the test, above, the only thing left to do is to get into the water and put your cylinders on. If properly configured and sized, your cylinders should hang in good trim. See this article about sidemount cylinder trim.
It should look like this:
Loop bungees work best when you place your lower cylinder attachment at 90-degrees… directly under the valve stem/manifold plug on the valve.
You must also get your cylinder band at the correct height. For instructions on that process, please see HERE.
The valve should be directly behind your armpit, on the side mid-line of your torso. The regulator 1st stages should be rotated inwards between your cylinder and your body. The cylinder valve handle should be pointing upwards.
I hope that helps some people. If you’re having problems with your own sidemount configuration, please do drop me a line – I’m happy to help. Video or photos do help with a diagnosis.
Positioning Sidemount Cylinder Bands
How to build your own DIY custom sidemount harness
Ultimate guide to sidemount cylinder trim
Fixing the sidemount training disappointment
Ultimate guide to setting up your sidemount harness
How to configure your sidemount harness
About the Author
Andy Davis is a RAID, PADI TecRec, ANDI, BSAC and SSI qualified independent technical diving instructor who specializes in teaching advanced sidemount, trimix and wreck exploration diving courses across South East Asia. Currently residing in ‘wreck diving heaven’ at Subic Bay, Philippines, he has amassed more than 9000 open circuit and CCR dives over 27 years of diving across the globe.
Andy has published many magazine articles on technical diving, has written course materials for dive training agency syllabus, tests and reviews diving gear for major manufacturers and consults with the Philippines Underwater Archaeology Society.
He is currently writing a series of books to be published on advanced diving topics. Prior to becoming a professional technical diving educator in 2006, Andy was a commissioned officer in the Royal Air Force and has served in Iraq, Afghanistan, Belize and Cyprus.