Imagine, for a second, the Swiss Alps. The silvery mountain lakes and impossibly dramatic crags tilted at all angles. A snowy, timeless place – laden with plunging valleys, snaking glaciers and postcard towns, home to ice climbers, off-piste skiers and dog sledders. Oh yeah, and an unlikely group of pioneering submariners.

Frogmen? At this altitude? It sound's unlikely, but the emergence of a new band of aquatic adventurers is exactly why I find myself in a fancy tin can, drifting towards the distant floor of Lake Lucerne in Central Switzerland. Down, down, down, away from the Alpine idyll, into a strange underwater realm. Going deeper, with every breath held.

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SubSpirit descends into the murk / Courtesy of Subspirit

Inside my metal cell – dubbed P-63 Subspirit – the digital gauge above a bug-eyed glass cockpit displays minus one, then two, then three metres. Swiftly, the depth plummets, a steady run through the teens, before hitting the minus-20s, 30s and 40s, as if an elevator punching for the penthouse. The counter reaches minus-60m, and I feel weightless. The atmosphere is of nervous expectation. Then, by minus-80m, there comes a heavy, hollow silence, followed by a soft thud as the craft lands gently on the lake-bed. Only landing on the moon could feel more dramatic.

I peek through the thick bull’s-eye window. Outside sits a silhouette of rusting iron: frozen-in-time railings, a broken wheelhouse with sand and silt coating the floor. Shipwrecks often exist in a state of stasis – the ice-cold water acts as a preserver and the sun never rises at such depths – so we hover towards it slowly in the darkness, still keeping our distance so as not to disturb the past.

Peering at the wreck of the Motor-Naue Portland

For a shipwreck like the Motor-Naue Portland, this twilight world is a silent one. There are few fish this deep in mirror-clear Lucerne, and what perch, trout, and pike there are hiding in the wreck’s lower deck find themselves in a place suspended in time. The miniature Titanic is a sunken tomb – the captain came down with the vessel in 1953 – and, at nearly 50m in length, also the largest shipwreck in Switzerland. It's a haunting sight; one that utterly encapsulates the intrepid thrills of the submariner's life.

“Underwater exploration is an addiction,” says our pilot, Philippe Epelbaum, as the searchlight ominously silhouettes the wreck. “The feeling I get underwater is of eternity. And every moment spent here is one of discovering something new. Maybe even for the first time.”

P-63 Subspirit is his brainchild and, as the founder of the enterprise, Epelbaum is now the proud holder of the only license to run a passenger submarine in the Alps – a classification that allows him to share his wild hobby with members of the public. 

Philippe Epelbaum – more Cousteau than Cameron / Credit: Mike MacEacheran

Dressed in a silver bomber jacket – complete with a Subspirit mission patch of his own design, recalling the golden era of NASA expeditions – Epelbaum is no eccentric billionaire in the Elon Musk or Jeff Bezos mould.

Far from it. More Jacques Cousteau than James Cameron, the entrepreneur and Subspirit CEO is foremost an underwater Scuba expert; a longtime technical diver who has been employed by the Swiss police, military and environmental groups for the past two decades to solve underwater problems. Of all the jobs on his CV, recovering missing persons during search and rescue operations were by far the most sobering.

Underwater exploration is an addiction... the feeling is one of eternity

But the life aquatic is what matters to Epelbaum, and that inspired him to dream big. After so many decades of wreck diving, cave diving, deep diving, drift diving – heck, all the diving – he wanted to go deeper, for longer, and was attracted by the fantasy of running his own submarine. As the sonar emits its familiar metronomic ping inside the cabin, he tells me that, after buying P-63 – first built by an Austrian company in Bregenz in 1987 for scientific research – he dedicated three years to giving the decrepit, 6.5-tonne, 5.5m-long capsule a complete overhaul. “Down to the last screw,” he adds.

The sub is something of an underwater UFO / Courtesy of Subspirit

Before long, the submarine was back in the water on 214m-deep Lake Lucerne, close to Epelbaum’s home in Stansstad – effectively a suburb of Lucerne and from where the craft still launches. Following numerous trials, the first passenger trips launched in October last year. Today, Subspirit has a licence to dive to 300m with three passengers onboard, plus the capability to go 100m deeper if necessary, to where the fish look like ink blots. There is no duty free or drinks trolley on board, but there is a ‘dry toilet’ in case of emergencies and survival time on the craft is factored to be 96 hours. Claustrophobes need not apply.

The idea for the enterprise was multifaceted: to feed Epelbaum’s dream and learn more about the underwater world of shipwrecks, but also to explore the ecology of Lake Lucerne and the damage done to marine life by human rubbish. The sub is also part aquatic classroom, part underwater UFO – and once the initial thrill of being so deep in a gigantic sardine can dissipates, questions are posed and talk turns to sustainability, limnology (the study of lakes) and, in my case, how the bloody hell the submersible works.

“You can compare it to an empty bottle that’s pushed underwater,” said Epelbaum, concisely. “When you let go, it pops back up to the surface.” 

The author, acclimatising to his new surroundings

To reassure those of a nervous disposition, the submarine is always accompanied by a surface boat, skippered by retired diver and Epelbaum's longtime friend Guido Mathieu, who operates the sonar and is in continuous radio contact with the underwater pilot. The irony being that the engineer has an irrational fear of confined spaces. Will Mathieu take the plunge himself? “Maybe one day.” 

Besides Motor-Naue Portland, another shipwreck in the vicinity is Vitzanove, which sank in 1999 during Cyclone Lothar, the worst European windstorm of the 20th century. Arguably more thrilling (or will be) is a Swiss army plane from the 1940s. This sits at more than 200m and is an adventure that’s being mapped out for 2023.

Perhaps surprisingly, for a country like Switzerland with no access to open sea or ocean, there is a precedent for this sort of trailblazing behaviour. As a young boy, Epelbaum had his mind blown by the story of Swiss oceanographic pioneer Jacques Piccard who, along with the American Don Walsh, was the first man to reach the deepest point in the ocean.

Still hard to fathom today, the pair dived to 10,916m (almost seven miles) beneath the surface of the Pacific to Challenger Deep, the very bottom of the Mariana Trench, before leaving a rich legacy of aquatic exploration. To some extent, 59-year-old Epelbaum has picked up the baton.

The little sub that could returns to the surface / Courtesy of Subspirit

All too soon, we began our slow-motion ascent back to the surface. Seventy minutes after retreating from the pristine world of Alpine summits above our heads, the submarine breaks the surface and the sensation – of rushing water and of sunlight flooding back into the capsule – sets my heart racing. Yet the main takeaway isn't of profound relief, but of longing. On opening the hatch, I don't gasp for the icy air as I’d anticipated. I'm left wanting to flip the door back over quickly – to descend down into the world-enlarging deep once more.

A submarine trip on Subspirit costs from CHF490 per dive per person. To book a trip, visit For further information on accommodation and travel to Lucerne, visit and

We are scientists – three more fantastic journeys

We are scientists – three more fantastic journeys
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