Mastering the Four Foundations of Sidemount Diving

The importance of posture

The importance of posture

I thought this would be a good time to look at some of the overarching foundations that make up a good sidemount diver. We’ve all seen bad examples of sidemount divers and I am sure you have found some very good ones too. So what separates the good and great from the rest?

For me, it is the foundational skill set. The basics if you like, practiced over and over so that they become second nature. A good sidemount diver is easy to dive with. They execute their dive plan well, with near perfect stability in terms of buoyancy control and trim. They move efficiently through the water and have minimal to no impact on their surroundings. They are easy for boat crews to work with regarding equipment management and getting in and out of the water.

So what are these foundational skills that we need to master? Let’s take a look:

Foundation 1 – Master Your Equipment

It should go without saying that you must know your equipment, how it functions, its maintenance requirements and how to set it up for a dive and store it post-dive. For sidemount diving, beyond the standard dive equipment of exposure suit, mask, fins etc. you will need to set up your cylinders, regulators and sidemount harness.

Ideally, your cylinders will have modular valves meaning one right handed and one left handed. This means you can orientate them to have both valve openings facing in towards your body which provides the opportunity to protect your regulator first stages.

Steel or Aluminium? Which one you chose depends on the diving you will be doing. There is no absolute rule but generally I will use 11 litre (80cuft) aluminium cylinders in fresh water and/or with a wet suit and 12 litre (95cuft) steel cylinders in salt water and in particular for dry suit diving. The reasoning is mainly around buoyancy and the amount of weight you want to carry on your system. Remember, aluminium cylinders become neutral to positively buoyant below around 100 Bar and are very buoyant at 30-50 Bar.

For both your regulators and sidemount harness, I recommend going for dedicated sidemount systems. There are many hybrid harnesses on the market from reputable brands but unfortunately these harnesses are a compromise by definition and are over represented in the poor examples of sidemount diving you will see. I know you can lay blame on the diver and not the equipment but the truth is dedicated sidemount systems tend to be more streamlined, easier to set up and much easier to gain stability and trim.

Foundation 2 – Master Stability

This skill is the foundation of everything that follows. Without stability in the water it is very difficult to perform skills and they will break down when you are task loaded or under the pressure of an emergency. Stability itself comes from correct weighting, correct positioning of weight on your sidemount harness, correct body position, correct operation of your BCD, the ability to use your lung volume to influence your buoyancy, correctly trimmed cylinders, good gas management and correct overall trim. I know this sounds like a lot and it is. But stability is the absolute hallmark of a good diver and the ability to hold a position in the water, without finning or moving your hands will serve you well in all of your diving. I spend a large amount of time on my courses ensuring students have stability dialled in and we revisit this often as we layer sidemount diving skills on top of this foundation.

Foundation 3 – Master Sidemount Skills

Sidemount diving itself is easy once a diver is stable in the water but there are some skills that separate a good sidemount diver from the rest. Efficient donning and doffing of cylinders both on entry and exit from the water including stowing hoses. Good sidemount water entry technique be it, from shore or from a boat platform. Gas management, regulator switching, checking pressure gauges, and of course propulsion techniques including, frog kick, helicopter turns, and the backwards kick.

I have found that having a process or system for each skill works best. Here I mean having a specific, well thought out, method and order in which you do things. A good example is cylinder donning for which you will always don your primary or left cylinder first before donning your right, secondary (long hose) cylinder.

Foundation 4 – Master Emergency Drills

Whenever we enter the water, we need to be mindful that we are entering a foreign environment that is very unforgiving of mistakes or complacency. Learning and practicing emergency drills until they are burned into our subconscious will build a skillset that can be relied upon in an emergency.

Top of the drill list is, Out of Air (OOA), not only because of the urgent risk of drowning but also because OOA is also a precursor to other diving incidents such as DCS and lung overexpansion injuries. Mastering the S-Drill where each diver takes turns at being the donor and receiver in an OOA situation is essential as is practicing the S-Drill at the commencement of every dive. This level of practice will provide the greatest chance of success in a real emergency. Other emergency drills include, valve shutdown drills for a regulator or hose failure, regulator second stage “free-flow” drills, BCD inflator drills and bungee breakages. Mask removal and replacement drills can be independently practiced and then combined with other drills as skills develop to provide a cascading failure scenario. Not only are these drills a real test of your skills they also help you to bed in stability and awareness while you are occupied with the specific tasks of a drill.

A couple of important notes re drills. Firstly, they should be practiced at shallow depths until perfected, ideally 6m or so. This lessens the risk of an accident in the event of a catastrophic fail performing the drill. Also let’s not forget that we are diving for leisure. It should actually be fun to drill and test yourself. Don’t be too hard on mistakes, this is why we practice and a mistake is just a sign some more work is required.


Within each of the foundational four pillars is a myriad of skills and drills that make up a sidemount fundamentals course. Practicing and perfecting each of these skills should be an ongoing effort and a matter of personal pride for a good sidemount diver.

I hope you found some value in this blog, let me know your thoughts, do you agree, disagree or have another perspective? I’d love to know.

Dive safe,