Managing Multiple Stages in Sidemount Cave Diving

Carrying one stage cylinder in sidemount is relatively straightforward.

Two stages require more planning.

Three or four stages change the equation considerably.

As the number of cylinders increases, the diver has to think about more than simply finding enough attachment points. Cylinder weight, buoyancy changes, drag, propulsion, regulator hose routing, cylinder rotation, and the order in which cylinders are staged all become important.

There is no single configuration that works best for every dive. The right approach depends on the primary sidemount cylinders, whether the diver is swimming or using a scooter, whether setup dives are possible, and how the stages will be carried and rotated throughout the dive.

Start With the Primary Sidemount Cylinders
More Cylinders Mean More Buoyancy Change
Swimming or Scootering Make a Difference
Setup Dives Change What Is Possible
Rotating Cylinders When Breathing From Them
Rotating Dragged Cylinders
Top and Bottom Staging
Dragging Stages
Two Stages May Be Very Different From Four
Think About the Entire Dive
More Stages Don’t Automatically Mean Better Planning
Configuration Should Follow the Dive
Final Thoughts

Start With the Primary Sidemount Cylinders

One of the biggest considerations when carrying multiple stages is the choice of primary sidemount cylinders.

Aluminum Primary Cylinders

Aluminum cylinders can make carrying multiple stages considerably easier. They are lighter on land, and their underwater characteristics can make a multi-stage configuration easier to manage. When carrying three or four stages, the weight difference becomes increasingly important. The diver is already carrying significantly more equipment. Adding large steel primary cylinders to that configuration can make the entire system substantially heavier.

Steel Primary Cylinders

Steel cylinders have advantages in sidemount, particularly because of their more consistent buoyancy characteristics. But those advantages have to be considered alongside the additional weight when multiple stages are added.

With two stages, the difference may be manageable. With three or four stages, the additional weight can become much more noticeable.

The question therefore isn’t simply: “Which primary cylinders are better?”

It’s: “Which primary cylinders make sense for the entire configuration I’m carrying?”

A cylinder choice that works extremely well with two primary tanks may not be the best choice when four additional cylinders are involved.

More Cylinders Mean More Buoyancy Change

Weight isn’t the only consideration. Every cylinder that changes from full to empty changes its buoyancy characteristics. With two primary cylinders, the diver already has to manage the buoyancy changes that occur as gas is consumed. Add several stages and those changes become much more significant.

A diver carrying four stages may experience substantial changes as cylinders are:

• consumed
• rotated
• moved
• and eventually staged

This means the configuration has to work throughout the dive, not simply at the beginning.

A setup that feels perfectly balanced with all cylinders full may behave very differently after several cylinders have been partially consumed or staged.

Swimming or Scootering Makes a Difference

How you move through the cave is another major consideration. A configuration that works well while scootering may not be ideal for swimming.

Scootering

A scooter provides propulsion without requiring the same fin movement as swimming. That can make carrying multiple stages easier, particularly when cylinders are positioned where they might otherwise interfere with the diver’s legs.

With several stages, reducing the amount of equipment that interferes with fin movement becomes increasingly important.

Swimming

Swimming introduces another consideration: Cylinder interference with the fins.

If stages are being dragged behind the diver, the cylinders can occupy the same space the diver needs for an efficient fin stroke. This becomes particularly noticeable when carrying two dragged stages. The diver may have plenty of gas and a technically workable configuration, but the cylinders can make propulsion inefficient or uncomfortable. For a long swim, that matters.

Setup Dives Change What Is Possible

Not every cave dive requires carrying every cylinder from the surface to the furthest point of penetration. Setup dives can dramatically change the equation. Instead of carrying all the stages simultaneously, cylinders can be transported during earlier dives and staged at appropriate locations along the planned route. The result is a much simpler configuration on the primary exploration or penetration dive.

For example, a diver who needs four stages may not need to carry all four at once. Some can be placed ahead of time.

This reduces:

• drag
• weight
• task loading
• cylinder interference
• and buoyancy changes during the dive

Setup dives therefore aren’t simply a convenience. They can fundamentally change how many cylinders a diver can reasonably use.

Rotating Cylinders When Breathing From Them

Carrying multiple stages creates another issue that becomes increasingly important as the number of cylinders increases.

Which cylinder is actually being breathed?

Some divers have a preferred hose-routing configuration when breathing from a stage. If the preferred routing requires the stage cylinder to be positioned in a particular location, the stages may need to be rotated to place the cylinder being breathed from in that position. With one or two stages, this isn’t particularly complicated. With three or four stages, it becomes a much more significant part of the dive.

Cylinder rotation needs to be deliberate and predictable. The goal isn’t simply to move cylinders around until the regulator is accessible. The entire configuration should remain organized as cylinders are rotated.

Rotating Dragged Stages

The same principle applies when stages are being dragged. If two stages are being dragged behind the diver, they may need to be rotated to bring the cylinder being breathed into the preferred position. This becomes especially important when the diver has a particular hose routing preference.

A stage that is easy to breathe from when it is in one position may be awkward when it is rotated into another. The diver therefore needs to consider not only where the cylinder is carried, but also where it needs to be positioned when it becomes the active breathing cylinder.

Top and Bottom Staging

One approach to carrying multiple stages is to distribute them around the primary cylinders.

For example, stages can be positioned:

• above the primary cylinders
• below the primary cylinders

This can create a relatively organized configuration and distribute the cylinders around the diver.

With aluminum primary cylinders, carrying stages both above and below can be particularly manageable because the primary cylinders themselves aren’t adding as much weight to an already heavily loaded system. The configuration can also keep the stages relatively close to the diver’s body. But there are trade-offs.

More cylinders in different positions mean more equipment to manage, and the configuration must be tested throughout the dive rather than judged only while everything is full.

Dragging Stages

Another approach is to drag one or more stages. This can become particularly attractive when using large steel primary sidemount cylinders.

Rather than placing multiple stages directly alongside the body, dragging two stages can simplify the configuration. But there is a significant trade-off when swimming. The dragged cylinders will affect overall trim. They can also interfere with fin movement. This may be manageable when using a scooter, but it can become inefficient during a long swim. The best choice therefore depends heavily on how the diver will be moving through the cave.

Two Stages May Be Very Different From Four

It’s tempting to develop a configuration that works with two stages and simply add more cylinders. That doesn’t always work.

Adding a third and fourth stage can change:

• the diver’s overall weight
• drag
• buoyancy characteristics
• trim
• cylinder positioning
• fin clearance
• regulator access
• and task loading

The configuration should be evaluated as a complete system. Don’t assume that adding another cylinder is simply a matter of finding another place to clip it.

Think About the Entire Dive

One of the most important questions is: What will this configuration look like at the end of the dive?

A multi-stage configuration can change dramatically as cylinders are consumed and staged.

Consider:

At the beginning

All cylinders should be full. The diver has maximum gas weight and maximum cylinder buoyancy characteristics to manage.

During the dive

Some cylinders become partially consumed. They may need to be rotated into different positions.

As stages are deposited

The diver becomes progressively lighter. Cylinder locations change. The configuration becomes less cluttered.

On the return

The diver may have a completely different configuration from the one used during the initial penetration.

The system has to remain manageable through every stage of this process.

More Stages Don’t Automatically Mean Better Planning

There is a temptation in technical diving to think that carrying more gas automatically creates a safer dive. It doesn’t. Additional stages bring additional complexity.

Every cylinder adds:

• weight
• drag
• buoyancy changes
• trim changes
• equipment to manage
• regulators to manage
• attachment points
• and another potential source of task loading

The goal should be to carry the gas required for the dive in the most efficient configuration possible. Sometimes that means carrying more cylinders. Sometimes it means using setup dives. Sometimes it means changing the primary cylinder choice. And sometimes it means changing the dive plan.

Configuration Should Follow the Dive

There is no universal multi-stage sidemount configuration. A diver making a short swim with two stages may have completely different requirements from an explorer making a long scooter dive with four.

Likewise, a diver using aluminum primary cylinders may choose a different stage configuration from someone using large steel cylinders.

The best setup is the one that balances:

• gas requirements
• cylinder buoyancy
• total weight
• drag
• trim
• propulsion
• accessibility
• and the ability to manage the cylinders throughout the entire dive

The configuration should serve the dive. The dive shouldn’t be forced to accommodate an arbitrary configuration.

Final Thoughts

Managing multiple stages in sidemount is less about finding the maximum number of cylinders you can carry and more about finding the most efficient way to carry the cylinders you actually need.

• Primary cylinder material matters.
• Propulsion matters.
• Setup dives matter.
• Stage positioning matters.
• Cylinder rotation matters.
• And the number of stages matters.

Two stages may be relatively simple. Three or four can transform the entire configuration. As the cylinder count increases, every weakness in the setup becomes more obvious. The goal is therefore not simply to carry more gas. It’s to create a system that remains balanced, streamlined, accessible, and manageable from the beginning of the dive to the end.

In complex cave diving, how you carry the gas can be almost as important as how much gas you carry.

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For a complete overview of how these elements work together, see The Complete Guide to Sidemount Diving Configuration.

Readers of this article can receive $10 off the book Sidemount Diving when purchasing directly from the website.

Use code STAGE10 during checkout.

Related Articles

• How to Properly Rig Your Top Mounted Stage Cylinders in Sidemount Diving
• How to Properly Rig Your Bottom Mounted Stage Cylinders in Sidemount Diving
• Proper Sidemount Stage Rigging for Cave Diving
• Steel vs Aluminum Cylinders in Sidemount
• How to Choose the Right Sidemount Cylinders
• How to Properly Manage Gas in Your Cylinders