On the protected southern coast of Curaçao, a tropical island in the Leeward Antilles 40 miles north of Venezuela, sits a massive, Cold War-era Dutch naval ship, housing something remarkable.
The boat serves as the Caribbean outpost of U-Boat Worx, a builder of personal submarines based in the Netherlands, which hopes to bring its underwater machines to the masses. I was there for a test run of an otherworldly experience that, until recently, would have been out of reach for all but the world’s wealthiest.
This particular beach, with its consistently calm sea conditions, was ideal for a plunge to a seafloor as dark and strange as the surface of the moon. The submersible I stepped into (U-Boat Worx’s Super Yacht Sub 3) followed the trail of a sunken, algae-encased guide rope down the island’s steeply pitched bathymetry, until the sunlight slipped away. The water color changed from mouthwash green to a bruised blue to storm-cloud gray, and finally into an unyielding blackness swirling with white sea snow.
Since their invention in the 17th century, submarines have mostly been used for war, commerce and science. Now, they’ve become the latest frontier for pleasure cruisers.
“In 2007 we went to the Monaco Yacht Show to introduce our subs to boaters and people thought it was a joke,” Erik Hasselman, commercial director for U-Boat Worx, said in clipped, Dutch-accented English. “They thought we were this crazy group of students with a prototype, and nobody thought it was real. Then a trickle of superyacht owners began to buy them, and now everyone with a yacht over 150 feet is at least considering one.”
To date, U-Boat Worx has sold 40 subs and has 15 more in production. Depending on make and model, personal subs tend to range from $2.5 million to $3.5 million — excluding the price of the $35 million yacht. But U-Boat Worx recently debuted a series of cheaper, two-seater models called Nemo, with standardized features and a simpler operating system that doesn’t require a professional. (U-Boat Worx offers Nemo owners a two-week training course that includes theory and 20 training dives.) It costs $1 million — the price of, say, a very nice house in the New York City suburbs.
In its quest to sell more submersibles, the company is introducing a shared-ownership program based in Curaçao, Bonaire and the south of France that allows customers to split the cost of ownership into eighths (plus training), for about $154,000 each.
In other words, submarine ownership can now be enjoyed by a particularly successful orthodontist.
A submarine ride involves a lot of trust in the technology. At depths of 1,000 feet, water pressure can reach about 440 pounds per square inch — something like a large silverback gorilla balancing on an SD card. Drowning at those depths wouldn’t exactly be the issue; most human lungs would crumple immediately if they were exposed to that amount of pressure, resulting in instant death.
Before I boarded the sub, I listened to Mr. Hasselman enumerate a number of safety measures in place in case of an emergency: 96 hours’ worth of air, extra food and water, redundant communication systems, a land-based safety command in constant contact with the pilot and a rescue sub at the ready. The moment of the safety protocol discussion that inspired the most confidence came when I perused the thick waiver form and noticed that a large chunk of it was devoted to slipping and falling when walking along the dock toward the sub.
Mr. Hasselman ventured that U-Boat Worx vessels were among the safest modes of transportation in the world. “We’ve done 3,700 dives without incident,” he said with a smile.
The unlikely catalyst for the personal sub’s raised profile was the cruise industry. “Back in 2015 we made our first delivery to a cruise line,” Mr. Hasselman said, “and that changed the general perception because it’s big business. If a cruise company is doing something, then it must be proven and foolproof.”
Today, several cruise lines use submarines to sate their guests’ demands for adventure. For instance, Seabourn Cruise Line treats its excursions to the Arctic and Antarctic like safaris — bringing along ornithologists, marine biologists, geologists and others as part of the deal.
Submarines play a vital role in those experiences. Seats aboard a 45-minute polar dive start at $899. At a time when an envy-inducing video posted to social media is its own kind of currency, for some, that’s a sound investment.
Personal subs aren’t just for sightseeing. Carl Allen, an entrepreneur who sold his family’s business in 2016, owns a vessel built by Triton Submarines, U-Boat Worx’s main competitor. Triton, which is based in Florida, is best known for taking the financier and adventurer Victor Vescovo to the deepest part of the Mariana Trench — nearly seven miles below sea level — in a titanium-hulled model in 2019. (Mr. Vescovo’s vessel broke a depth record previously held by the filmmaker James Cameron of “Titanic” fame.)
Mr. Allen also owns Walker’s Cay, an island in the northern Bahamas, and uses it as a base for a sub-powered treasure-hunting operation.
“Once you get below about 150 feet, there’s a good chance of seeing something no one has ever seen before,” Mr. Allen said. He counts among his finds musket balls, gold bars and a large emerald which he believes to be part of the bounty of the famous Nuestra Señora de las Maravillas wreck. (Mr. Allen has opened a maritime museum in Freeport in conjunction with the government.)
For Mr. Allen, an experienced scuba diver, diving in a submarine has an air of glamping. “You don’t need tanks anymore to see all the stuff that’s down there,” he said. “You have a cocktail and put on your music and go down a few thousand feet and have a blast.”
Not everyone feels that way about the experience. For some submarine newbies, claustrophobia is a major concern.
The passenger compartments on most models are cramped by anyone’s definition. (Mr. Allen said he recently had an F-16 pilot aboard his sub who likened it to the cockpit of a fighter jet.) And there are no bathrooms, which means voyagers might want to think twice about that cocktail.
But it’s not just claustrophobia. The particular way the light refracts through seawater and the four-inch-thick acrylic bulb that protects passengers from the water can induce a fear of falling out of the boat. “We’ve had a few issues with panic attacks,” Mr. Hasselman admitted, “but we can usually tell if something is up before we actually begin.”
The curve of the window distorts objects underwater, too, so they look both smaller and closer than they actually are. For example, the Stella Maris, a 300-foot freighter intentionally sunk off Curaçao, looked like a bath toy to me as the sub puttered around it.
But to be hundreds if not thousands of feet deep in the ocean is to feel swallowed whole by something impossibly large and ceaselessly unforgiving. There can be a strange peace in that. Once the world outside turns black, the pilot often asks if the passengers would like to turn off the sub’s search lights and sit for a moment, dark and still, at the bottom of sea.
