Keeping pace with sharks: Inside the world’s fastest personal submersible

Built to chase sharks and dive to 300 metres, U-Boat Worx’ €10,000,000 Super Sub is redefining underwater exploration. Jaclyn Trop descends beneath the Caribbean to experience the fastest personal submersible ever created and discover why yacht owners are embracing a new era of deep-sea adventure...

It started with an email from a client. “He already owned one of our submersibles,” says Roy Heijdra, marketing manager for Dutch sub builder U-Boat Worx, “but he said he wanted something that could keep up with sharks.”

U-Boat Worx spent the next several years developing a €10 million (£8.6m) Super Sub, the world’s fastest personal submersible yet built to go this deep – a recreational machine capable of diving 300 metres below sea level.

Finally, three and a half years after the client hit send on his email, his dream sub is ready for delivery, but before it is tendered aboard his yacht, U-Boat Worx invited select media to its Willemstad, Curaçao, base for a plunge.

On dry land, the hulking craft resembles a cross between a rocket ship and a remote-controlled car. As it’s lowered by pulleys and cables into the azure Caribbean waters, it looks more like a sly alligator, and I’m nervous as I slide down into its belly and take my ergonomic seat.

“Everyone still excited?” our pilot, Nigel Ruiters, asks. “Hatch is closed. No going back.”

He settles into the Recaro motorsport-grade bucket seat behind his command centre and we begin to descend. Surprisingly spacious, the sub is more roving IMAX theatre and less cramped instrument of naval warfare.

At 30 metres below sea level, Ruiters points out a lone French angelfish, flapping one fin in greeting. At 70 metres, I remove my sunglasses, which have become redundant. At 140 metres, Ruiters switches on the headlights so that we can trawl the island’s famous Stella Maris shipwreck at Curaçao National Marine Park. The 90-metre freighter was sunk in the 1980s as an artificial reef, but the sinking went awry, and the boat slipped deeper than intended.

From the submersible’s spacious enclosure,  a marvel is revealed that only the world’s most technical scuba divers have seen. The coral reef growing around the rusted freighter pulses  with life. Schools of brightly striped fish  and effervescent sponges appear oblivious to  the Super Sub, perhaps because its curved  acrylic pane makes the reef appear much closer than we actually are.

After orbiting the wreck, Ruiters instructs us to buckle our five-point harness seat belt because we are going to descend quickly. The sub’s quad-thruster set-up plunges us 290 metres below sea level in seconds. We leave the fish behind, passing through gradients of blue until there is only blackness. My sense of orientation starts to slip away, until Ruiters switches on the headlights.

We see nothing but illuminated jet streams  of sea dust rushing past the sub’s panoramic windows, providing the heady sensation that  we are not under the sea but breaking into the mesosphere as we rocket to the moon.

“We see that controlled flight on the water really piques clients’ interest,” Heijdra had told us earlier. “Instead of a regular submarine that descends vertically, the Super Sub represents a new concept in speed and handling. It’s a new way of exploring underwater.”

With room for two passengers and a pilot,  the nine-tonne submersible represents a new frontier: a vessel for superyacht owners with a penchant for exploration. The Super Sub’s maximum speed of nine knots is about three times faster than U-Boat Worx’ second-fastest model, the seven-passenger Cruise Sub. CEO Wilbert Versteeg called it “an underwater hypercar with ocean-floor views”.

The Super Sub’s design features an oblong, rocket ship-like body punctuated by an acrylic viewing bubble. Measuring 6.5 metres long – roughly the same as a large living room or  baby blue whale – the sub boasts a streamlined  design, an advanced wing system and 100kW of horizontal thrust that enables it to climb and descend at a 45-degree angle.

The project’s original mood board began with “a droplet of water, the most hydrodynamic form nature ever made,” says engineer Gido Grooten. “The shape is an expression of speed.

“The hardest part of designing the sub was matching the aesthetic with the mechanics,” Grooten continues. “We had to design the form around the batteries, thrusters and buoyancy control systems to create something that looks good and works.”

Engineered for agility, the Super Sub uses a sonar system that scans the seabed to adjust its trajectory – a useful feature for exploring steep terrain such as the reef we just visited.

Less than an hour after our initial descent, the Super Sub breaks through the surface where we alighted, at U-Boat Worx’ operations centre next to the Curaçao Sea Aquarium. We may have left sea level 45 minutes earlier as civilians, but when we re-enter, it is with the mantle of explorers, our underwater flight complete.

First published in the June 2026 issue of BOAT International. Get this magazine sent straight to your door, or subscribe and never miss an issue.