Sidemount diving originated in Cave Diving and Cave Exploration as the lower vertical profile of this twin cylinder method allows for deeper penetration into the tight confined areas of the underground systems around the world. Sidemount diving is now the preferred configuration for open circuit extended range, cave and deep exploration dives.
Sidemount has been adapted into the Open Water environment for many of the other benefits it can offer a diver as well. Using 'independent' double cylinders a diver has additional redundancy in the unlikely event of an equipment malfunction and offers much better visual and tactical contact with their gas supply. All valves, hoses, O-rings, and regulators are in close proximity to the diver and are within view at all times. The elimination of two large cylinders on the divers back also allows for easier mobility on a dive boat or land as the diver prepares to enter the water. Sidemount Diving must also be considered a method of gas management. Especially in Technical and Cave diving the amount of gas in each cylinder must remain relatively equal. This is accomplished by alternating breathing between each cylinder at a scheduled rate.
Some of the other benefits often touted are the easier ability to adjust a divers buoyancy or trim in the water. For the traveling diver it is also much easier to acquire single cylinders versus double cylinders at any diving location around the world. Now openwater sidemount diving is recognized and taught by almost all of the major training agencies around the globe.