Choosing a Sidemount Rig

"What sidemount system should I buy?"

This is one of the most common questions we hear from our students. While it appears to be a simple question at first glance, it's not quite that easy to answer. In fact, our initial response is always, "What type of diving do you plan on doing in sidemount?" No single system on the market, or even homemade, is perfect for every type of diving. The first thing a diver considering purchasing a sidemount system needs to do is consider the type of cylinders that will be used with the system.

At this time there are several commercial systems available to divers. However, not all systems are equal. While most can easily accommodate heavier steel cylinders, there are some that cannot. Our experience has been that anything less than a wing with 50 pounds of lift isn't very suitable for larger steel cylinders or smaller steel cylinders with stage cylinders, especially for divers who only dive wet. While there are modifications that can be done to counteract the extra weight of steel cylinders, they tend to add more bulk and complication to the system. There are enough commercial systems available with 50 pounds of lift or more that purchasing a system with less lift or one that requires the addition of an air bladder doesn't make much sense.

If a diver is planning on primarily diving aluminum cylinders, then the commercial lower lift systems or simple harness systems with an air bladder as an addition will work fine. Divers may also consider building their own sidemount system. These systems are simple enough, and with the minimal amount of lift needed, allow for a wide variety of choice for air bladders. While building a system can be done by most anyone, building a good system requires some knowledge of sidemount diving or conferring with an experienced sidemount diver.

Trying to make a sidemount system with 50 pounds of lift or more can be a little more challenging. Using one of the current commercial air bladders available can help simplify this process. However, if a diver wishes to build a system using a different air bladder, this will likely involve some modifications such as sewing additional material onto the outer fabric.

Once the type of cylinder is determined, the next question a diver needs to ask is what type of diving will be done in sidemount. There are several reasons to dive sidemount:

• to get into smaller cave passages
• medical issues
• added redundancy of independent cylinders and the ability to see the valves and first stages
• the increased stability of moving the cylinders closer to the center of gravity of the body
• the cool factor

If it's for any of the last four reasons, then there's really no issue as to what system is purchase except for the comfort of the harness. If the reason for diving sidemount is to get into smaller cave passages, then the attributes that must be considered are the profile of the system and the snag factor of the system.

The systems with less lift are, of course, the lowest profile systems available. But with that, divers are giving up the ability to use heavier cylinders. This is fine for some locations, but most of the cave systems in North Florida are in the 60-100' depth range, or more, and smaller cylinders won't allow for much penetration. With heavier cylinders, the profile must be a little higher, but you still want to keep it as low as possible. This is not the case with all of the commercial systems. So, be careful, and compare the profiles when shopping. One particular commercial system appears to be made specifically for the open water market than for cave divers.

Some sidemount systems have incorporated flexible webbing to help retract the air bladder when air is exhausted. While this appears to be a great idea, the webbing does present some issues. We have gotten caught up in the ceiling of very low passages and bedding plains by limestone formations jutting out from the ceiling in a standard system that does not have any webbing on the back. For the purpose of getting through really low passage, having anything on the back of the wing that can catch on formations sticking down from the ceiling can be counterproductive. A clean system without the add-ons appears better suited to this type of diving.

Finally, the comfort of the system needs to be assessed. Standard harness systems with shoulder straps that route to the rear of the system, in our opinion, aren't as comfortable as a harness with shoulder straps that route directly down to the waist strap. Many divers choose to mount backup lights on their shoulder straps. When the shoulder straps route to the rear of the system, it makes it difficult to mount lights in this location because the lights would be positioned under the cylinders making them difficult to deploy, and also uncomfortable because the cylinders would be pressing them into the diver's torso. Having shoulder straps that route directly down to the waist strap also makes the system more stable. With rear routed straps, the waist strap has two attachment points - the rear of the harness. With waist strap routed shoulder straps, the waist strap now attaches at the rear and is further stabilized a few inches apart from the center where the crotch strap attaches creating more stability in the harness.

Keep checking back. Our next post will cover common, and not so common, modifications to commercial sidemount systems.

Make sure you check out our website - Chipola Divers.

Why sidemount?

There's a common misconception by many divers that sidemount divers only go into small spaces. While that is one of the reasons for diving sidemount, it's not the only one. It's also not the most common reason for diving sidemount. Many divers choose to dive sidemount because the advantages of the system appeal to them or because of health related issues. And, yes, some even do it because of the cool factor.

Sidemount was originally created as a way for cavers to get past sumps they encountered in dry caves. The first sidemount rig was very different from the rigs we currently see being commercially produced by dive equipment manufacturers. It consisted of a simple belt with a loop on each side to hold the cylinders on the body of the diver. The tanks were positioned low on the body. The main advantage of this configuration was the simplicity of it. Cave explorers were more easily able to carry single tanks, rather than manifolded tanks, into the caves to the sumps where they would be needed. The harness system was also small enough to either be worn or carried in a small pack.

As cave diving in the UK progressed, cave diving was also experiencing its beginnings in the United States. Florida, well known for the thousands of fresh water springs, was the center of cave diving activity. Quite a bit of cave exploration had taken place in many of the known springs. But the passage that was explored was mainly large passage that could only be negotiated by divers wearing backmounted double tanks. This left miles of passage unexplored. Some divers began experimenting with the harness systems being used in the UK. The need for an air cell for buoyancy control was more of a factor in the Florida systems so divers began modifying jacket BCs for sidemount configurations.

Rather than bore you with more history of sidemount, we'll fast forward to today. In the early 2000s, the first couple of commercially available sidemount systems were produced and placed on the market – the Dive Rite Nomad and the Golem Gear Armadillo. While they shared many similar features, they also differed from each other in many ways, namely in the harness and the lift capacity of the wing. Today, we have over half a dozen commercially produced sidemount systems available to divers. Some of these systems are suited to cave diving, some are better suited to open water diving, and some are marketed for both cave divers and open water divers. While there are many divers who dive these systems unchanged out of the box, many also make modifications to suit their diving to these systems (more on modifications in a later post).

Sidemount systems continue to evolve as more and more divers experiment with it. Unlike traditional backmount systems, there will likely not ever be a standard sidemount configuration. While most divers begin diving manifolded backmounted double tanks for a specific purpose, such as technical diving, as stated earlier, divers begin sidemount diving for different purposes. As long as this holds true, a standard rig will not develop.

One of the original reasons divers started diving sidemount was to get into smaller passages. Not all passages are passable with backmounted cylinders. While the passage may be pretty wide, the floor to ceiling height doesn't allow passage of a backmounted diver. There are several passages located in the caves of North Florida that are only passable by lower profile sidemount divers. There are even several passages and caves that have significant size passages, but the opening to them is only large enough for a low profile sidemount diver. While backmounted divers have tried to pass through these openings, many fail, and the damage they are causing to the system is very evident. In this case, sidemount is using the right tool for the dive.

Some people dive sidemount for health related reasons. Whether it's a bad back or bad knees or ankles, removing 100 pounds of steel from your back can be an orthopedic miracle! Dissenters will argue that this requires more trips to the water and sidemount divers still need to carry tanks, but that's not necessarily the case. With a $40 truck cart from Wal-mart, tanks are easily rolled to the water from your vehicle in one trip. The second trip is one without any heavy tanks, or you can leave your truck cart at the water and get in (well, that is if you're not at Ginnie otherwise the cart might not be there after the dive). Once in the water, the tanks are much lighter and easier to handle. In the water, sidemount is also a lot easier on the diver's back. Moving the tanks to the side gets the weight mass off the spine. Moving the tanks down also allows a different body position in the water. While many backmount divers must arch their backs to maintain a horizontal position in the water, this isn't the case in sidemount.

Finally, there's the cool factor. I'm not going to elaborate on this type of sidemount diver. They are pretty easy to pick out. Fortunately, at least in my experience, there aren't too many of these, not in Jackson County anyway.

Keep checking back here for more on sidemount diving. And don't forget to visit our website - Chipola Divers.

Overhead and decompression training or not...

It's been a while since I've posted a new entry. Fortunately, it's because I've been diving a lot! Still diving quite a bit, but thought I'd get back here to post a quick note. The subject of this entry is the importance of overhead training.

The recent alleged death of a diver in the cave located at Vortex Spring brings this subject up. The diver had no previous overhead or decompression training, yet he had supposedly made several dives in the Vortex cave. There is videographic evidence of at least one dive he made there, so he was entering the overhead. The presence of several cylinders in the system also indicates he was probably doing decompression dives there.

Let's take a look at the type of cave Vortex is. The cavern zone at Vortex is not very large. Fifty feet into the passage and natural day light is no longer visible. However, several open water divers make the trek back to the gated grate located about 300' into the passage. While this isn't encouraged by Vortex management, the dredging pipe located in the passage, along with the holiday type lights that lead back to the Piano Room (the room where the grate is located) makes this cave somewhat inviting. Once past the grate, the passage narrows significantly and the ceiling drops closer to the floor. While the first 1000' or so is passable in backmount, there are a couple of sections where passage in backmount cannot be made without having contact with the cave. The average depth in from the gate through the backmountable passage is in the 110-120' range. At the point the passage becomes unpassable in backmount, it also drops down into the 150-160' range. At this point, one must be in sidemount. About 1400' into the cave is a tight restriction that makes passage without contacting the cave impossible. Exiting from this point is usually in low to zero visibility. This is definitely an advanced cave dive that requires trimix and significant experience.

Cave diving is a very safe activity IF the proper training has been completed and the five guidelines of accident analysis (proper training, continuous guideline, air management, appropriate gas mix for the depth, and good equipment that is well maintained) are followed. Violating any of these guidelines increases the risks significantly, the greatest risk coming with the guidelines in the beginning of this list. Not having the proper training is the number one reason for deaths in caves.

Cave diving training is intensive, requires the appropriate gear, and a great amount of dedication. It's not something someone can learn by reading about it in books or on the Internet. Of the approximately 600 documented deaths that have occurred in caves since we started keeping track of them about 40 years ago, a majority of those deaths occurred due to lack of proper training.

The following four guidelines are all taught in cave diving training, but someone who has not received that training may not be aware of the guidelines and how important they are to preventing incidents from happening. Air management is more than just diving to 1/3s. In fact, diving to 1/3s is the most liberal way to conduct a cave dive and there have been incidents and deaths that resulted even when this guideline was followed. Using the appropriate gas mix for the depth not only requires knowing what mix to use, but also how to follow an appropriate decompression schedule for that mix and the length of the dive. This requires additional training outside of cave diving training. Violating any one of these guidelines is enough to keep someone from leaving a cave alive. Violating more than one, or all of them, is a near guarantee that the outcome will not be good.

Cave diving training and decompression training are expensive and time consuming. The average cost to complete cave diving training is in the $2000-3000 range. This does not include the gear required to conduct these types of dives. Add another $3000-4000 for that. Then don't forget the decompression training. Depending on the level of training someone decides to pursue, this can range anywhere from $800-3000 just for the training. A cave like Vortex requires about $1500-2000 in training. There are also additional equipment costs. Breathing gas costs will also be about $100 per dive. Yes, this sounds expensive. It is expensive. But it's worth every penny if it brings you out of the cave alive.

It's not worth it to take shortcuts and try to do these dives without the training and experience they demand.

Don't forget to visit our website - Chipola Divers