Loved, hated, fatally misunderstood: sidemount diving attracts it all. What began as a tool for sump and cave exploration has transformed into a worldwide activity, attracting divers of all types and backgrounds. There are many myths and misconceptions surrounding sidemount diving, which can muddy the water of understanding. If you, like many others, are considering if sidemount is in your future, then you just found the right article! Hopefully, after reading, you will be better informed as to whether it is for you.
The Benefits of Sidemount Diving
Sidemount diving comes with an array of benefits, applicable to every diver of all levels.
1. Increased Gas Capacity
One of the major advantages of sidemount is that of increased gas capacity. By carrying twice as many tanks as normal, you have twice as much gas. This can be of major benefit for a variety of situations.
Firstly, by having more gas, you can perform much longer dives. If combined with nitrox diving, this can give you even greater dive times due to the increased NDL (No Decompression Limit). It is not uncommon for recreational sidemount divers to perform dives in excess of 120 minutes. This is a luxury for many divers who have never experienced a dive longer than the usual 40-60 minutes.
Secondly, for divers for whom their high breathing rate cuts their dive time short, switching to sidemount will be the key to unlocking more dive time. We can illustrate the effect of this by using a little bit of maths…
If we assume you dive with a standard tank size of 80 cu ft (11.1 litre) filled to 200 bar, that means you have 2,220 litres of gas in your tank (on a normal single tank dive):
11.1 (L) x 200 (bar) = 2,220 litres of gas
If we then assume you have a SAC rate (Surface Air Consumption rate), i.e. breathing rate, of 25 Litres per minute (which is very high – normal is between 14-18), we can then workout how long it will take you to consume all of your gas:
2,200 (L) / 25 (SAC) = 88 minutes
However, this is at surface pressure (1 bar). If we take an average depth of 15 metres (2.5 bar), then we can see how long it would take you to consume all of your gas at this depth:
88 (min) / 2.5 (bar) = 35.2 minutes
Clearly, your dives would be very short with such a high SAC rate, which would restrict you from diving in deeper sites and starting new diving adventures. Thus, by moving to sidemount, this problem would be solved (or at least greatly ameliorated), as you double your gas capacity:
22.2 (litres) x 200 (bar) = 4,440 litres of Gas
4,440 (L) / 25 (SAC rate) = 176 minutes (@ surface pressure) 176 (min) / 2.5 (bar) = 70.4 minutes (@ 15 metres)
Clearly, the difference is massive, with your dive times doubling for the same depth.
Additionally, this is calculated with a very high SAC rate, so for those with a lower one (which is very likely for the majority of divers), your maximum potential dive times will be even greater.
A third benefit of increased gas capacity is for that of emergency situations. For deeper recreational diving, the increased gas capacity is an excellent safety buffer, covering out-of-gas situations as well as accidental/emergency decompression incidents. It also makes gas sharing situations much less stressful due to the additional capacity.
By combining sidemount with nitrox diving, recreational divers will be able to extend their bottom time at deeper depths, without having to perform mandatory decompression stops. This is ideal for those wanting to expand their diving deeper without making the full transition into technical diving.
We are not designed for the underwater world. Apart from our lack of gills, and low tolerance to pressure, we are also severely unstreamlined in the water, unlike the dolphin or the seal, for example. This is not without consequence. Increased drag represents increased effort to achieve effective propulsion; increased effort results in an increased breathing rate. Not only does an increased rate of breathing deplete gas quicker, it also leads to greater carbon dioxide build-up, which itself contributes to increased narcosis as well as greater susceptibility to oxygen toxicity. This is, of course, in the extreme. However, it is still worth taking into consideration in the quest for optimising our diving configuration. This is especially true if diving in an area in which effective propulsion is vital, e.g. strong current/strong flow environments.
By diving in sidemount, we are reducing the amount of drag our body has to the minimum. Through aligning our tanks on our side, we present the minimum amount of surface area possible, making for optimised propulsion and a lower rate of breathing. This is critical in environments in which effective, continued propulsion is necessary.
Although more closely associated with technical diving, redundancy is of great benefit for all divers. Diving in sidemount provides you with unparalleled redundancy, giving you two separate tanks, with two separate first and second stage regulators. This puts you one step closer to being a fully fledged self-sufficient diver. This makes you a safer, better buddy to dive with, as your increased redundancy represents increased redundancy for your buddy/the whole team.
This added redundancy is also the perfect complement to deeper recreational diving, in which – in the event of a lost gas situation with one tank – you are still able to make it to the surface without having to rely on a buddy.
4. Trim & Stability
It would be incorrect to say that good trim and stability cannot be achieved in backmount configurations: it evidently can and is by thousands of divers everyday. However, it is arguable that sidemount makes achieving perfect trim a slightly easier task. Due to positioning the tanks on our lateral plane, we become much more balanced and stable, allowing us to naturally adopt a more horizontal position. If our tanks have equal buoyancy characteristics, then our body will naturally stay horizontal and level on all planes. We can swim at ninety degrees on our side, upside down, or just normally: we will, in all cases, remain stable. Compare this to a twinset. Although perfect trim is obviously possible and relatively straightforward to achieve, our centre of gravity is higher in a twinset and, consequently, we are more affected by changes on our lateral plane. For example, if we were to lean slightly to one side, the weight of the twinset will cause us to turn fully upside down (if we do not resist it). As a result, we require greater bodily tension in order to remain stable and in trim when diving in backmount configurations.
Sidemount presents the diver with a range of options regarding how to enter and exit the water. In this respect, sidemount diving is excellent for those suffering from any sort of physical disability. The ability to enter the water without your tanks, as well as don and doff them whilst in the water, opens up the world of diving to many who would not otherwise be able to handle their equipment.
I personally have seen sidemount diving used to enable those suffering from multiple sclerosis as well as those who have experienced major back problems, to continue diving. Not only does this advantage of sidemount allow people to continue diving despite physical problems, it also enables them to continue their diving education. If someone wants to enroll in an entry level technical diving course, no longer must they be subjected to the immense weight and bulk of a twinset – they can do it in sidemount (and they can do so reasonably up to 100m!).
Similarly, for those of smaller stature and/or for whom lifting heavy weight is not possible, sidemount allows them to continue to grow their diving experience and education. In this respect, sidemount is an amazing tool for opening access to the world of diving.
6. Access to Valves
This is primarily a concern for technical and cold water diving, but is also useful for recreational divers too. By having the tanks mounted by your side, you can easily see the first stage as well as access the handwheel of the valve. Compare this to your standard twinset, in which you cannot see the first stages and have to reach behind you (in a move of gymnastic-level flexibility for many people!) in order to open and close the valves.
In technical and cold water diving, the ability to open and close your tanks whilst underwater is of paramount importance to ensure your safety. In the event of a free-flowing regulator, for example, being able to reach and close your valve(s) is the difference between completing the dive safely, or potentially running out of gas and missing decompression stops. In a twinset, many divers find it difficult to access and close the valves due to the flexibility required to do so. This is particularly true for older divers, as well as for the sporty (who often have more muscle mass).
Similarly, for those who have suffered any shoulder injuries, reaching your valves is often a painful exercise. Therefore, by switching to sidemount, these simple (yet life saving) maneuvers will become far easier.
By having the valves, and therefore the first stages, directly in front of you, this can also make problem solving far easier. You can see for yourself if a first stage or valve connection is leaking, without having to rely on your hearing or buddy to know. This makes you a more self-sufficient diver, and thus a safer diver.
7. Accessing Specific Environments
Sidemount was first invented as a means to an end; it is a tool for overhead diving (specifically sump diving). Therefore, if you have a particular interest in a specialised type of diving – specifically wreck or cave – then sidemount is the perfect tool for the job. A wreck or cave enjoyed in the bliss and freedom of sidemount is a feeling quite like no other! Similarly, sidemount offers unparalleled safety in these tight-squeeze environments, in which – in extreme cases – you are able to fully remove all your tanks as well as the wing bladder.
8. Weight Reduction
For the travelling diver, switching to sidemount can actually save you a lot of weight and space in your suitcase. Sidemount harnesses are often minimal and lightweight in style and can be folded into very small sizes. Compare this to a jacket BCD or BP/W setup, in which size and weight are often issues when travelling.
For the underwater photographer, sidemount can make life easier. Due to having your back free from tanks, your spine is no longer locked into a fixed position, allowing for greater mobility and flexibility in the water. This, combined with increased stability, can make getting into awkward positions to take those killer shots that much easier. Similarly, sidemount divers gain more headroom, allowing you to move, turn and look upwards, free from obstruction. Another benefit of increased stability is simply that it makes holding a normal horizontal position much easier, allowing you to focus on your subject with greater ease. This greater ease of stability will reduce the need to move and readjust your position as much, which will in turn increase the chances of close encounters with wildlife without spooking them.
Similarly, if you want to access a tight restriction in order to get a specific angle, or focus on a particular critter, then you are free to remove a tank – or even go no-mount – in order to access the restriction. These things are simply not possible in backmount configuration. The only slight drawback of sidemount for photographers is that of increased gas management (having to consistently switch regulators throughout the dive), as well as stowing the camera when not in use (as the chest area is not as accessible in sidemount configuration). However, both of these issues can be overcome with a little foresight and planning, and are done so by many sidemount photographers everyday.
10. A Step into Technical Diving…
Sidemount diving is an excellent gateway into/taster of technical diving. For many people, learning sidemount diving informs them of their own ambitions. Some people will love it and realise that technical diving is the next step; others will realise that the simplicity of single tank, recreational diving is the boundary of their interests. In either cases, the diver will benefit: they will not waste future time and money.
The sidemount course often serves as a taster course for technical diving. It introduces the diver to managing more than one tank, introduces the long-hose and long-hose gas sharing, puts greater emphasis on trim and propulsion techniques, and in general – challenges the diver by introducing them to a completely alien equipment configuration. It is usually at this juncture that a diver realises where they want to take their diving. I know myself that enrolling in and completing my recreational sidemount course both confirmed and bolstered my desire to move into technical diving. And equally, if you realise that sidemount diving just isn’t for you, and by implication, technical diving, then at least you come out of the course with a greater knowledge of both yourself and diving.
Choosing Your Instructor
Arguably the biggest propagators of misconceptions about sidemount, poorly informed sidemount instructors do a lot of damage to the discipline. Sidemount diving’s precipitous rise to fame resulted in the certification of many instructors who had as great a knowledge of sidemount diving as the lay observer. Consequently, many divers have been taught and certified by these ill-informed/inexperienced instructors, resulting in the growth of unskilled sidemount divers (unsurprisingly!). As a result, a shadow has been cast over sidemount diving’s reputation. Sidemount is too complex for recreational divers… inconvenient to use on a boat… pointless for open water diving… the list of slurs goes on. Both fortunately, and unfortunately, these slurs against sidemount are false, and all result simply from a lack of proper training. Therefore, choosing the right instructor is essential to your success in the discipline.
So, how do I go about choosing the right instructor? you duly ask. There are a few basic questions to ask, and things to look out for when selecting a sidemount instructor. First and foremost:
1. What is your background in sidemount diving and how much experience do you have in the configuration?
This is an obvious but crucial question. With only a handful of dives in sidemount configuration, or even just a signature from an Instructor Trainer, an instructor can qualify to become a sidemount instructor. Thus, adequate experience is not a prerequisite. Therefore, finding out your instructor’s background and experience diving in sidemount is key. They do not necessarily need to have thousands of dives in the configuration to be acceptable, but a solid base of experience is required.
Often, a good indicator of their reliability is if they are trained to a higher level than they are teaching. For example, if you have the choice between two instructors, one being able to teach only the recreational sidemount course, the other being able to teach cave and/or technical sidemount courses, it is a likely bet that the latter instructor will be the better choice. Naturally, this will not always be the case.
However, it is likely that the more qualified instructor will deliver a better course, not only from being more experienced but also from seeing the configuration in a more holistic manner (i.e. seeing how sidemount changes and adapts when used in more demanding environments on more demanding dives). This leads to a greater understanding of the system, as well as the reasoning behind every minute component of it. Question number two:
2. How long will the course take?
There is more to this question than meets the eye. To meet the minimum course requirements takes two days. However, given the specialist nature of sidemount diving, not enough knowledge, experience and instruction can be passed on to the student in this timescale, in order to lay the correct foundations. Most famous, top instructors offer the course over 4-5 days, and emphasise both the fact that they will not necessarily certify everyone, as well as that if more time is required, then the course will be extended. This is a reliable indicator of a good sidemount (or any type of) instructor.
Conversely, alarm-bells should ring if the instructor emphasises that the course is ‘just another speciality’ with a ‘100% pass guarantee’ and ‘only takes two days to complete’. You may as well set fire to your money if you’re planning to enroll in a course like this – it would save you more time too! A knowledgeable, experienced sidemount instructor knows that the fine details of the configuration are of paramount importance to your success and enjoyment. Therefore, quick fixes and minimum course requirements are a recipe for failure. If your sidemount instructor explains in detail how the course will be laid out, with half-day to day-long equipment theory workshops, extended shallow skills dives, configuration fine-tuning, and an emphasis on teaching the fundamental skills and intuition necessary for sidemount, then you can be sure that you are in good hands.
Aside from these questions, there are also a few other things you can do.
Firstly, use the power of social media. If your prospective instructor has Instagram, Facebook, a blog, or any sort of online presence, check them out. See if they have pictures of their sidemount students, or at least of themself in sidemount. Are their tanks in trim next to their body? Are they continuously horizontal in the water column? Do they have weights strapped to the base of their tanks (if yes, alarm bells should ring!)? A basic, quick look at these things can tell you a lot about a prospective instructor.
In conclusion, if your interest is at all piqued by sidemount diving, enrolling in a course is the best thing you can do to find out the extent of this interest. And, if you do enroll in a course, ensure to find an experienced, reliable instructor who will give you the best grounding possible in the discipline.