In the early 2000s, if you walked onto a dive boat with two tanks strapped to your sides instead of your back, you were considered an outlier—a cave diver who simply hadn't learned how to socialize with "normal" recreational divers. Today, sidemount diving has exploded beyond the sump and the cavern. It dominates technical wrecks, penetrates pristine coral reefs, and is rapidly becoming the configuration of choice for solo divers, photographers, and even warm-water vacationers.
But here is the hard truth: Sidemount is not a short cut; it is a discipline.
Many divers try sidemount once, feel like a barnacle-covered anchor, and declare it "unstable." Others succeed brilliantly, gliding through restrictions with the grace of a fighter jet. The difference between struggle and success is not talent or money. It is adherence to a few immutable principles. Sidemount- Principles For Success
This article deconstructs the sidemount configuration into seven core principles. Whether you are rigging your first set of AL80s or trimming out steel LP85s for a 6-hour cave dive, these laws apply.
Many sidemount systems have an optional rear clip to secure the tank's butt to a plate on your back. For recreational sidemount, avoid this. A rear clip forces the tank to stay rigidly parallel to your spine. This destroys your ability to articulate your hips and maneuver in tight spaces. Success requires dynamic tank movement. Leave the rear clip for cave diving with stage bottles. The Dorsal (Back) Clip Trap Many sidemount systems
Your head is the rudder. If you look down, you go down. Look up, you go up. For sidemount, you must maintain a neutral spine. Imagine a laser beam shooting out of your sternum. That beam should be angled slightly downward—approximately 10 to 15 degrees. If your head is cranked back looking at the reef above you, your hips will drop, and your tanks will turn into anchors.
During a safety stop, most divers look up to check their gauge or the surface. In sidemount, this drops your hips. Dropped hips = tanks roll up = you cork to the surface. Success means keeping your chin tucked toward your chest during all stops. Look at your computer by lifting it, not lowering your head. The Sidemount Shutdown Drill (Do this every dive):
Your sidemount wing is tiny—usually 18 to 30 lbs of lift. Do not use it to correct poor weighting. First, get your weight perfect. You should be able to hold a 10-foot (3m) safety stop with empty wing and 500 PSI left in both tanks. Your wing should only be used to compensate for wetsuit compression and the weight of the gas you will breathe.
The Roll-Off Warning: If your tank is too horizontal (valve at your hip, boot at your knee), you cannot reach your own valve to shut it down in an emergency. The "Leaning L" keeps the valve within a hand's reach of your left or right shoulder.