From the alpine mountain lake to the cenote – My sidemount adventure with the XDEEP Stealth 2.0
A lonely mountain lake in the Alps, crystal clear water at only 4 °C.
Below me, rock walls plunge into the depths, and above me, sunbeams dance through the cold water column. Two tanks hang streamlined at my side – my constant companion, the XDEEP Stealth 2.0 Sidemount Jacket , provides me with buoyancy and a sense of security.
My name is Stephan (known as @diving_steph on social media), a TDI Sidemount Instructor and Sidemount CCR Cave Diver. I've been exploring the underwater world with the sidemount system since 2013.
Entry into the sidemount world – passion and training
It all began over a decade ago when my best friend Stefan and I decided to try sidemount diving. At first, it was just a curious diversion, but it quickly developed into a passion—and eventually, a career: Today, I train sidemount divers myself.
One of my most important mentors along the way was Patrick Widmann – Stefan's brother, world-renowned cave diver, explorer, and instructor trainer. Patrick was not only instrumental in the development of the XDEEP Stealth 2.0, but is also Training Director at KISS Rebreathers and co-owner of Protec Dive Centers in Mexico . From him, I learned what it means to dive sidemount in every environment – from deep, icy mountain lakes to tropical caves.
The first attempts were frustrating. Hooking up bottles, doing drills, unhooking bottles – over and over again. I had to master every move. It took some time before I truly understood the benefits. But this investment was more than worth it.
In 2013, when I started sidemount diving, this configuration was hardly known in Tyrol. At the lake, people treated me as if I were from another planet. Stefan was there from the very beginning – and we still dive sidemount together today.
Cold mountain lakes – redundancy and tranquility in Austria’s waters
The journey begins in my homeland, in the deep lakes of Austria: Achensee, Blindsee, Attersee, Wolfgangsee – names that stand for clear, cold water.
Here, I learned early on the value of redundancy: Two side-mounted cylinders mean more peace of mind – a second, independent air source is always available. At a depth of 40 meters at just 4°C, a regulator can freeze and go into free flow. But with the sidemount system, I always remained calm: All valves and regulators are conveniently located under my arms, in my field of vision, and accessible at any time. This level of control saved my dive the very first time my regulator froze over.
But sidemount isn't just about technical safety. With the Stealth 2.0, I can easily trim myself horizontally, even in a thick drysuit. The weight system distributes the weight ideally around my hips, allowing me to float stably and glide smoothly past branches and rock formations.
In a remote mountain lake at about 2,000 meters above sea level, I was able to carry the bottles to the water individually – no need to carry a heavy double pack on my back. Two 12-liter bottles are enough – first pass them into the water, then dive in. My back thanks me.
As soon as I submerge, the silence of the lake envelops me. The only sounds are my breathing and the quiet hiss of the inflator. Since combining the system with my KISS Sidewinder rebreather , it's even quieter—no bubbles, just the sound of my breathing and the gentle flow of oxygen.
Underground – Sidemount adventures in caves and grottos
From the mountains to the underground: Budapest, Mexico, Dominican Republic, Sardinia – my cave dives show what sidemount is really made for.
The system was developed in cave diving to give divers maximum mobility in tight passages. And that's exactly what I feel when I glide through crevices—no bulk on my back, no annoying bottlenecks.
In Budapest, I had the opportunity to dive a flooded mine. With line markers and lights, I squeezed through narrow tunnels. In moments like these, every inch counts. The Stealth 2.0 hugs the body like a backpack—less is more here.
In Mexico's cenotes, I often dived with stage tanks or a sidemount rebreather to penetrate deep into pristine tunnels. Sunbeams filtered through jungle shafts, transforming the caves into glowing green cathedrals. With approximately 19 kg of buoyancy, the XDEEP Wing offers enough reserve for multiple tanks—yet remains incredibly slim. In these caves, every detail counts. I've learned to trust my configuration blindly.
Whether in the Dominican Republic or Sardinia, every cave has its own character. But my setup remains familiar: modular, adaptable, reliable. It opens up spaces that would be inaccessible with a backpack. I remember a moment: pushing through a narrow passage, suddenly entering a vast stalactite chamber. I pause, breathe calmly, and feel: This is exactly where I belong.
In the open sea – Sidemount on journeys in tropical seas
Egypt, the Maldives, Thailand, Croatia – my Stealth 2.0 accompanies me everywhere. Many bases lack dual tanks or special tech equipment. With sidemount, it's no problem: two 12-liter single cylinders, and off I go – with redundancy, agility, and space savings in my luggage.
On flights, I leave the heavy backplate at home. The Stealth weighs under 3 kg, fits in my carry-on luggage, and has never let me down. In Thailand, for example, I was able to spontaneously do a deep wreck dive because two single cylinders were readily available.
In the water, I'm impressed by the streamlined shape: less resistance in currents, better proximity to the reef. On a wreck like the Giannis D, I can fit through narrow hatches where others get stuck.
And last but not least: extended bottom time. Two tanks mean almost twice as much breathing gas. While others ascend, I stay with the manta rays for a while longer – safe, relaxed, and present.
I often spark interest on the boat: "What kind of system is that?" – And sometimes even experienced divers spontaneously join in. I demonstrate instead of persuading.
Conclusion – Freedom underwater & desire for the next step
This trip showed me: Sidemount is more than just equipment.
It's a flexible system that adapts to any environment—from icy mountain lakes to tropical oceans, from narrow caves to open-sea wrecks. It's changed the way I dive—and allowed me to grow as a diver.
For advanced divers who want to take the next step: Learn sidemount.
It opens up new possibilities, deepens your understanding of buoyancy and equipment – and brings you closer to the magic of the underwater world.
In combination with the KISS Sidewinder rebreather, it is a system with a future – quiet, powerful, modular.
I'm grateful—for Patrick, for my friends, for every underwater experience. And every time I put on my Stealth, I get a tingling feeling: Where will this journey take me this time?
If I could inspire you, I'm happy.
Dare to try sidemount.
The underwater world awaits – with hidden corners, quiet spaces and a feeling of freedom that only sidemount can give.
Happy Bubbles – and always good air!
Stephan (@diving_steph)
