Erik Hasselman, commercial director of U-Boat Worx, sits inside a C-Quester 3 submarine in the harbour during the Monaco Yacht Show this week. Photo: Bloomberg.
Erik Hasselman, commercial director of U-Boat Worx, sits inside a C-Quester 3 submarine in the harbour during the Monaco Yacht Show this week. Photo: Bloomberg.
Graham Hawkes, founder of Hawkes Ocean Technologies, poses for a photograph with a model of a Super Falcon Submersible vessel during the Monaco Yacht Show (MYS) in Monaco, France, onThursday, Sept. 26, 2013. Over 100 of the world's luxury yachts will be displayed in Port Hercules during the 23rd MYS which runs from Sept. 25 - 28. Photographer: Balint Porneczi/Bloomberg *** Local Caption *** Graham Hawkes
Graham Hawkes, founder of Hawkes Ocean Technologies, poses for a photograph with a model of a Super Falcon Submersible vessel during the Monaco Yacht Show (MYS) in Monaco, France, onThursday, Sept. 26, 2013. Over 100 of the world's luxury yachts will be displayed in Port Hercules during the 23rd MYS which runs from Sept. 25 - 28. Photographer: Balint Porneczi/Bloomberg *** Local Caption *** Graham Hawkes

Graham Hawkes, inventor of the “underwater plane”, made his debut at the Monaco Yacht Show this week in a bid to entice billionaire boat owners to take the plunge.

“This is literally like flying underwater,” Hawkes, a UK-born ocean engineer who has spent decades designing cutting-edge diving suits and submarines, said in an interview. “Once you’ve done that, you don’t want to do anything else.”

Hawkes is one of four submarine vendors who, for the first time, are all at the Monaco show – one of the world’s top yacht gatherings – to display multimillion-dollar hi-tech wizardry they say makes perfect accessories for the wealthy.

U-Boat Worx, Triton Submarines and Seamagine Hydrospace Corporation, along with Hawkes Ocean Technologies, are betting the super-rich will want to go beyond cruising on luxury boats worth tens of millions of dollars.

They see annual sales of private, small luxury submarines going double-digit over the coming decade from a few now.

As the yacht size has stretched – this year saw the launch of a record-holding 590-footer (180m) called the Azzam – so has the list of distractions onboard. Soaking in a jacuzzi, shooting hoops on a floating court or playing a baby grand Steinway piano no longer cut it.

“There is a change in attitude of super-yacht owners,” said Bert Houtman, founder and chairman of the Netherlands-based U-Boat Worx, surveying two of his submarine models on display quay-side in Monaco.

“They’re fed up with drinking white wine and riding Jet Skis, so they’re looking for another thrill.”

The submersibles on offer cost from around $1.5 million (R15m) to $4.2m, depending on their size and underwater range.

The current global fleet is estimated at under a couple dozen, including on private yachts such as Octopus, owned by Microsoft co-founder Paul Allen.

There’s one on Necker Island, British Virgin Islands, owned by Richard Branson, founder of Virgin Group, and another on a tourist island off Costa Rica, where a 300m dive costs $1 800 per person.

U-Boat’s five models, equipped with bubble-shaped acrylic windows, can hold between two and five people and sink to between 100m and 1 000m underwater.

Rival Triton, which is based at Vero Beach in Florida, is pushing the depth limit to 1 650m for similar battery-powered technology.

Storing an 8 164kg submarine elegantly on a designer yacht can be a challenge.

Makers urge owners to have bespoke boats conceived with subs in mind or invest in a “shadow” vessel to transport these toys and tenders, smaller speedboats that accompany super-sized yachts.

Private submersibles are “a way of exploring for things that no human has ever seen”, Marc Deppe, Triton vice-president of sales and marketing, said in an interview.

“For that you need depth.”

Sharks, hydrothermal vents and sea mounts are among the wonders the more jaded wealthy could admire from an air-conditioned capsule, complete with panoramic views and a sound system, according to Deppe.

There are also man-made attractions.

In July, U-Boat took Russian President Vladimir Putin 60m underwater in the Gulf of Finland to see The Oleg, a 19th-century shipwreck.

One of Triton’s subs was used in an oceanographic research campaign to film the elusive giant squid. The company is using the feat to develop relationships between rich submarine owners and research institutes too poor to acquire the hardware.

“A lot of guys who are billionaires have profound financial accomplishments and are now concerned about their legacy,” said Deppe.

Super-yacht professionals are guarded about the identity of their clients so, without revealing names, Deppe says this is already happening.

The companies themselves train and grant submarine pilot licences through in-house-designed courses.

Safety features include a “dead man” signal that has to be sounded by the pilot every 10 minutes or the submarine automatically returns to the surface.

Hawkes’s underwater flying machines differ from the others. While his resemble soft-edged airplanes with bubble-shaped cockpits, the others are more like UFOs.

“They’re like a helicopter, we’re like a Lear jet,” he said at his stand in Monaco, which faces million-dollar yachts on display for sale or charter. The backdrop is a poster of him and Branson cruising in an underwater plane snapped just before they crossed paths with a Great White shark.

“Our goal is to fly and play with the big animals,” he said. “Now that’s magic.” – Tara Patel from Bloomberg