Ben Reymenants, our Training Director is one of the deepest cave divers in the world. This article appeared in the TDI Asia news and perhaps shows some of the mindset behind what it takes to complete some of the most challenging diving in the world, but also the experience our instructors have behind them when teaching.

He made a cave diving record in Thailand in Sra Keow Cave. This is his story…


Cedric’s wet note arrives from the habitat. Eventually Maurizio deciphers the writing: “240M – BAD VIZ. ROPE ENTANGLED. TELL BEN TO USE 186M LINE.” On the positive side, it seems that none of the staged gases have been used as bailout.

Sra Keow cave diving
Sra Keow lake

After a clumsy giant stride, I quickly disappear in the muddy pool. At 12m, visibility is less than a meter. Clusters of staged deco tanks pass me by as I drop fast, and after just 4 minutes I pass the 60m mark. Moments later in my haste I fail to have a close look at a T-junction at 80m and put a line marker marking my descent. This error will get me into trouble later…
The 150m tie off is smaller than I imagined and I find entangled line where the next tied spool should be – not good. Plan B: follow the old line to Dr. Mike Gadd’s final tie-off from our last expedition at 186m. As I reach it, I tie off my OMS reel on the old line, unlock the reel, and drain my wing.

Darkness begins to close in. The walls of the cave have disappeared now and the only visual reference I have is a spinning reel in front of my eyes and the neon yellow glow from my Liquivision X1 computer. The Suunto Vytec I brought as a backup has been asleep since 150m.
What the hell am I doing here?

At around 190m, High Pressure Nervous Syndrome starts to manifest. At 210m, my shaking hands are a problem – I’ve excluded a pressure gauge from my rig for fear of implosion. Instead, I’ve opted to keep the manifold on my twinset closed, and as soon as breathing became difficult, I can open it. As I have three tanks behind me, this would indicate I’d used a third of my gas supply. Unsure if my hands will work, I decide to attempt it, breathe my third bail out tank empty, and then ascend. The sound of the tanks equalising as I twist the knob open is music to my ears.

Suddenly I reach the bottom, composed of fine ochre silt, and I gently sink in it up to my ankles. I look down at my gauge to see my depth: 239m. A quick scan reveals no further descent points. Soon I’ve nearly sunk to my waist and instinct tells me it’s time to leave. I start inflating my wing and rise clear, dropping visibility below me to zero. “Slow ascent, slow breathing.” I repeat my mantra in my mind. Minutes turn to hours. I reach my first stop exactly at my 186m tie-off. Soon after the Vytec bleeps to life at 150m again – runtimes on both computers match like nothing ever happened.

The rest of the ascent goes smoothly until I hit the T-junction at 80m. In my haste I failed to put an extra line marker to show my descent direction and now I am looking at both an orange and a yellow arrow pointing diagonally up and away from each other. Taking the wrong line would result in a best case scenario of life in a wheelchair. I curse myself for being so hasty. Upon inspection one side looks vaguely familiar and I take it. I will know if it is the right line in 30 minutes at the 60m station.
Half an hour later I arrive at 60m. No tanks in sight. My heart stops….

At 59m my head bumps into the bottom of the deco tanks. The silt buildup has camouflaged them to resemble a rocky outcrop. Relief floods through me and I clean the second stage clear of a half pound of mud and shrimps and start breathing my deco gas.

Not having a schedule for 240m, I use my 250m plan. This poses an inconvenience as there is no one to take my stages from me and I’m forced to clip them on. Dragging 14 tanks along produces a sound like the peal of church bells and keeps the curious shrimps at a distance.

At 39m I switch from my 21/50 mix to my 33/43 mix, and within thirty seconds a wave of nausea hits me. After a few moments I’m convinced that I’m suffering inner ear decompression sickness due to the nitrogen gas forcing itself back into my inner ear. I think of other divers that have experienced this on extreme dives and I can see the headlines already in the magazines: ‘Diver drowns in own vomit 40 meters from cave entrance’.

But that’s not going to happen. Not today. I wedge myself between two rocks and begin to alternate between gas mixes, and soon the wooziness subsides.
Maurizio arrive shortly after and I am soon 6 tanks lighter. I also left a station with drinks, a hood and gloves here and I make use of it. A few hours later, the 21 meter stop appears and I’m again in overload; pushing 4 tanks ahead of me while dragging 9 tanks behind me. Laurent arrive and needs two runs to get the rest of the tanks to the surface. After 5 hours I finally reach my 12m stop. I’m cold, dizzy, and hungry and I can’t see a thing.

Some time later I finish my last stop and it’s time to get into the habitat. I surface next to a smiling Cedric who has been in here for the last three hours. Wedging myself on my primitive seat, Cedric hand feeds me hot soup brought by the surface support.

I feel like shit. “Bottom at 240 huh?” I ask Cedric. He looks at me with wide eyes and says, “I tied the spool on the 150m rock, started descending and suddenly the entire line, including the rock, came falling past me. I caught the main line before it disappeared, ascended, made a new tie off and wrapped all the loose line into a knot.”

I’m speechless. If he had lost the main line it would have meant certain death. He’d have had no way to find the exit passage again. We finish our soup and squeeze potato puree out of plastic bags while breathing an 80% oxygen-rich nitrox mix from surface supplied hoses, all of which tastes of polyvinyl.

Three hours later it is finally my turn to leave the habitat. Dr. Luba Matic, our dive doctor, shows up to escort me out of the habitat on a full face mask. I spend fifteen minutes ascended due to pain in my knees that comes and goes, and spend a half hour in the pond floating around before returning to gravity.

The dive site is a mess. There are tanks everywhere, hoses left and right, suits, fins, food containers. Suddenly there is a flash of white; a lightning strike followed by a peal of thunder and two seconds later it is pouring down.

I arrive back in Phuket at 1am with a truck full of muddy dive gear. Oh how I love this game.

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