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what is sidemount bcd for technical scuba diving?

Whether you are a regular diver or not, you have most likely either seen or encountered sidemounted bcd for scuba diving. Regular scuba divers would certainly have encountered divers that have dive tanks under each arm and no dive tank on their back. These are sidemount divers.

The new wave in the diving community is side mount. Side mount was used exclusively by a few several years ago, but now it has become mainstream. At least one sidemount bcd is featured by almost every manufacturer. Sidemount bcd specialties have recently been included in the standards and policies of PADI and NAUI.

Using double cylinders or sidemounts for diving originates from the world of tech diving. We know that wearing a traditional cylinder originates from the Aqualung which was invented by Jacques Cousteau, but it is the British cave diving world that first used cylinders under the armpits for diving.

British caves are known to be very narrow and low-ceilinged areas that are difficult to navigate, while those in the USA are big, open tunnels. In order to give yourself the best opportunity to penetrate these caves you need to take up as little room as possible. This is the reason it is better to wear your cylinders on the side instead of on the back. They are slung in a custom harness, and hang under each arm. All equipment used is standard apart from a special kind of bcd.

When diving in small tight spaces such as ship wrecks or small caves you are able to maneuver much easier if you are using sidemount bcd for scuba diving. A diver requires far less space in the water especially when entering a narrow passage.

Recreational divers find this rig type comfortable and versatile. Some of these systems are among the lightest diving systems in the world. They weigh extremely little and the harness supports all of the more common diving configurations, with only minor adjustments whether using one or two tanks. The most important aspect of this system is properly placed cylinders. The diver's water movements will be inefficient with poor buoyancy if the cylinders are out of trim.

A bungee system that runs from behind the diver's back to under the arms holds the tank valve in place with the use of a safety clip. Each tank has its own short-hose pressure gauge and regulator. Hoses must be carefully sized for each diver and the hose port locations.

Valve leakages are very unlikely as they are able to be quickly detected by the diver. The switching and shutting down of cylinders is much easier. The regulators and valves are in clear view of the diver and not located on his back. Emergency procedures are much easier to carry out.

As far as problems with this system are concerned, sidemount does not scale quite as easily as the traditional backmount cylinders. Backmounted bcd's are able to be easily converted from double cylinders to single cylinders. Sidemount bcd for scuba diving will always require double cylinders even if the reef is a shallow one.

It is likely that you will require two bcd's, one for doubles/sidemount and the other for single cylinder diving. Prolonged deep dives need to carry more than just two cylinders because a diver cannot use the same gas to breathe throughout his dive. A different gas is used while doing the bottom part of the dive and several gasses are used during the ascent and the descent.

Divers who make use of a backmount system carry the extra cylinders as stage bottles, slung over and under their arms. When using sidemount cylinders you quickly run out of side area. You can have two more cylinders when diving backmount, regardless of how many you are carrying under your arms. The placement of the cylinder on your back allows for better weight distribution. Sidemounts make it more difficult for long walks before you reach the water. You can get the feel of it by carrying two shoulder bags with evenly distributed weight and going for a walk, and then trying this with a backpack.

There are a wide variety of training courses on offer for using sidemount bcd for scuba diving. These cover technical, recreational, exploration and specialty classes worldwide. Getting formal training from an experienced instructor is highly advisable as equipment needs to be modified and optimized for each diver. A customized fit and configuration is important for making sure the diver is in the correct horizontal plane.