Sidemount Diving: Exploring Benefits and Drawbacks for Your Underwater Adventures

My journey as a diver began in traditional BCD PADI single tank open water diving, but my quest for improved trim and buoyancy led me to explore various diving styles. Encounters with sidemount divers in Mexico ignited my fascination with this configuration during its early days, characterized by limited equipment options but an undeniable allure. Transitioning to cold water diving, I mastered the drysuit before delving into tech diving, ultimately excelling in Advanced Open Circuit Trimix in sidemount configuration.

Embracing twinset diving in Iceland provided a smoother learning curve, given my background in single tank backplate and wing diving. A pivotal tech diving expedition to Truk Lagoon revealed practical limitations of both twins and sidemount configurations, prompting my investment in a JJ CCR (Closed Circuit Rebreather). Today, I navigate various diving setups, including sidemount, single tank, 12L (~80 cf) twins, and 7L twins, while prioritizing underwater photography over deeper dives.

Through firsthand experience with diverse diving techniques, I've gained invaluable insight into their respective strengths and weaknesses, informing my approach to diving and equipment selection.

So what exactly is Sidemount?

Sidemount diving is a diving technique that involves wearing the scuba cylinders on the diver's sides rather than on their back. Sidemount is usually conducted with two tanks, however a variation known as "monkey mount" is sometimes used for one tank. Many of the benefits are reduced when diving with just one tank though.

While it is challenging to trace the exact origins of sidemount diving, its roots can be traced back to the development of cave diving in the 1960s. Cave divers needed a way to navigate the tight passageways and restrictions found in underwater cave systems. They discovered that by carrying their cylinders on their sides, they could greatly increase their maneuverability and access areas that were previously unexplored.

The earliest known documentation of sidemount diving techniques can be found in the 1970s explorations of the Wookey Hole Caves in the UK by cave diving pioneers. These divers experimented with various equipment configurations and harnesses to optimize their buoyancy, trim, and maneuverability.

As the sport of cave diving evolved and gained popularity, sidemount diving techniques spread among the cave diving community. Divers began to refine and share their experiences, leading to the development of dedicated sidemount systems and equipment.

In recent years, with advancements in materials and manufacturing processes, major diving equipment manufacturers recognized the demand for sidemount diving gear and started developing purpose-built sidemount BCDs (buoyancy control devices), harnesses, and accessories. These advancements have made sidemount diving more accessible and customizable for divers of various levels of experience.

Benefits of Sidemount Diving

1. Enhanced buoyancy and trim: One of the primary benefits of sidemount diving is the improved buoyancy and trim characteristics it offers. By placing the cylinders on the sides, divers can achieve a streamlined posture, which improves their overall hydrodynamics and reduces drag. By having one tank located on each side it is a very balanced way to dive and it avoids the pendulum effect that you get when using a single tank centered in the middle of the back.

2. Reduces back strain: Traditional back-mounted systems can put pressure on the diver's spine and cause discomfort during long dives. Sidemount diving eliminates this issue, as the weight is distributed on both sides of the body. Due to being able to carry each tank independently it can make it much less stressful to take the equipment from cars to shore entries also.

3. Increased accessibility and flexibility: Sidemount equipment is easy to configure and adjust according to individual diver preferences. This adaptability allows divers to maneuver through tight cave systems and wrecks with ease, accessing areas that would otherwise be challenging or impossible to reach. It is very easy to remove your tanks underwater allowing you to access restrictions much easier than any other system.

4. Redundancy and safety: Sidemount diving involves using multiple gas cylinders, which provides a redundant gas supply. In case of an equipment failure, divers have an additional source of gas readily available, which significantly enhances safety and increases peace of mind underwater. This redundancy is especially crucial during overhead diving, both for true ceilings such as cave or wreck ceilings or theoretical ceilings such as decompression obligations.

Drawbacks of Sidemount Diving

1. Initial investment and gear requirements: Compared to traditional back-mounted systems, sidemount diving can be more expensive, as it requires additional equipment such as harnesses, regulators, and specially designed sidemount BCDs. The initial investment might be a deterrent for some divers, especially for those who are just starting their diving journey or have a limited budget.

2. Additional training and practice: Transitioning from back-mounted to sidemount diving requires proper training and practice. Divers need to familiarize themselves with new equipment and techniques, including cylinder management, gas valve manipulation, and underwater trim adjustments. Of all the diving techniques I have tried, sidemount requires the most in water practical training to master; this can be expensive and time consuming. Initial equipment set up can also take a lot of back and forth to get completely right.

3. Limited weight capacity: Unlike back-mounted systems, which can accommodate larger cylinders, sidemount diving typically involves using smaller cylinders. While this is generally sufficient for recreational diving, technical and extended range divers may find the limited weight capacity challenging when planning longer dives or conducting decompression stops.

4. When traveling you may not have access to the same tank type as you might use at home, moving from steel to aluminum for example can require a lot of additional set up and time, especially when it is your first time using a new tank type.

Conclusion

Given these benefits and drawbacks you may decide that sidemount could be for you or might not be, but after all the diving I have done it all actually comes back to one simple question: what type of diving will I be doing, and what is the best system for that?

Today, sidemount is the system I dive the least, but this is because of the type of diving I am currently doing. I dive in Iceland where I don't dive in conditions that require sidemount. I mainly dive in the open ocean or lakes, where the benefits of twin 7L far outweighs the sidemount for me. However, if I was to plan a trip to Mexico for cenote or cave diving then I would immediately switch back to side mount. This would by far be the best tool for those dives. Also if I was to plan a shallow (sub 130 ft / 40m) wreck diving trip, sidemount would be my first choice.

For any trimix dive trips where I would be using trimix and deco for most of the dives then I would immediately move towards a CCR again.

All diving techniques are tools. Ultimately you just need to deploy the best tool for any job.

When looking for an instructor to try any new type of diving, no matter what it is, be wary of an instructor that sings the praises of any one technique or equipment manufacturer over another. In a great instructor you need to find someone who understands the benefits and drawbacks of all types of diving, equipment and manufacturers. Someone that will inform you based on experience and knowledge gained over time doing many different types of diving.