Being the first person to see something is an experience that can surpass all others, create exhilaration that borders on euphoria and, maybe most important, win every dinner-party conversation for a decade. Craig Barnett, the sales-and-marketing manager for Triton, says the desire to have that kind of experience is a key reason why so many yacht owners want personal submarines.

“Once you have your Ferrari and your yacht and your private jet, and you’ve traveled the world, it’s all about augmenting your reality,” he says. “How can you enhance your experience? With a yacht, you’re scratching the surface of the sea. With a sub, you’re discovering a whole new level.”

In fact, according to insiders at Triton as well as U-Boat Worx, yachtsmen are embracing more than just the spirit of adventure. They’re ordering semicustom and custom submarines the same way they look beyond production yachts to custom builds, wanting to have a half-dozen or more friends and family members underwater with them, as well as fineries that range from leather interiors and Bluetooth sound systems to Champagne chillers and more.

U-Boat Worx alone is now offering 100 options on its various sub models, and Triton is seeing yacht owners outfit subs in increasingly interesting ways. Hulls No. 9 and 10 are now in build of the Triton 3300/3, which is the company’s most popular model, able to dive with three people (including the pilot) to 3,300 feet. “You can fit them out with extra cameras and all that stuff for documentary filmmaking,” Barnett says. “You can load them up with ­scientific instrumentation. We have one owner who uses it for archaeology and salvage. They’ve been practical and useful. Now, in the past 18 months, we did the concept and engineering with Aston Martin to take the sub into the serious luxury realm. It’s not just a fanciful idea. We intend to build them. That will happen.”

The rise in popularity of submarines is coinciding with increased interest in expedition and support yachts, which clients and yacht builders have been embracing for a number of years now. The current generation of yachtsmen is looking beyond ports such as St. Barth’s and Monaco; they want the ability to cruise far, far beyond the ­traditional itineraries that their parents enjoyed in the Caribbean and Mediterranean. About 100 explorer yachts of at least 80 feet length overall are in build today, Barnett says, and in May, the Monaco Yacht Club hosted the first conference focused on expedition-style yachting. Charter clients also are looking for go-farther opportunities, such as spending a week aboard the 254-foot expedition yacht Legend in Antarctica, where charters come with a submarine.

In April, as part of the Five Deeps Expedition to reach the deepest points in each of the five oceans, Victor Vescovo (above) became the person who has dived the deepest in human history. He was aboard a Triton submarine specially built for the cause, one that—unlike some previous ­specialty subs—could be used like the space shuttle, going down and up and back down again to explore. “It opens up a whole other level,” says Craig Barnett, sales-and-marketing manager for Triton. “That sub could dive every day for as long as we had supplies, provisions and a weather window.” And with the Five Deeps Expedition scheduled to conclude this year, the sub is already on the brokerage market, ready for a new owner to take possession as early as ­September. The asking price, Barnett says, is $48.9 million, which includes the 223-foot ­research vessel the sub loads onto for transport. Meanwhile, Triton is using its R&D knowledge from the project to inform new models. “We made some major breakthroughs,” ­Barnett says, “and that will affect ­everything we do in the future.”

“It’s such a big and growing sector,” Barnett says. Today’s yachtsmen “want to do the Northwest Passage, go to remote areas in the ice, have exploration and adventure, and with that desire for unique experiences comes the submersibles.”

As consumer demand for private subs has grown, so has the variety of subs available and the options for designing and outfitting them. U-Boat Worx offers 20 models within five series, while Triton offers nearly a dozen models within three series. Both ­companies have lighter-weight models designed specifically for crane loading on and off superyachts or support vessels.

And while yacht owners a decade ago thought of a personal sub as a utilitarian toy that came off a production line, today’s owners are thinking about them more in the ways they think about custom-built tenders.

“You want a continuity of experience between the yacht and the submersible,” Barnett says. “We can of course paint the exterior any color you want, and now we can work with the interior designer of your yacht. If you want white, carbon fiber and sporty, we can do that. If you want wood and classic with matching leathers, we can do it that way. It’s the same as with outfitting a luxury tender.”

Costs for anything customized of course come in a range, and the same is true of today’s ­submarines. Triton’s entry-level model goes for $2.7 million, while its largest sub—a seven-seater—retails for $5.25 million.

Barnett says yacht owners see those prices as being in line with, say, a customized helicopter that lands on the bow.

In fact, he says, the way subs are discussed aboard yachts could soon rival the way owners talk about their onboard choppers: “I can see submersibles potentially becoming as popular on yachts as helicopters. Maybe not every yacht has one, but every yacht gets built with the capability to have one on board. You would order your ­helicopter, and then order your submarine.”

2008
J.D. Ducanes, captain of the 164-foot Trinity Mine Games, trains on a Triton 1000/2 (carrying two ­people to 1,000 feet). It becomes the first private submarine available to guests aboard a charter yacht.

2012
Triton receives an order to build its third 3300/3 (carrying three people to 3,300 feet) for use on a superyacht, within a few months of the first 3300/3 doing its maiden dive off Grand Bahama.

2019
With explorer yachts surging in popularity, Dutch yacht builder Oceanco unveils a 345-foot concept design with room for not one, but two submarines, along with a helicopter and a land vehicle.