When Dan McGuire left his job at Harpoon to help open a new brewery in Weymouth, he faced a daunting commute from his home in Charlestown.

So whenever he can, he goes by boat.

He’s also cruised off Maine, around Cape Cod, out of Portsmouth, and in the Gulf of Mexico when he went to Houston to watch the Patriots play the Texans.

McGuire, who is 36, doesn’t own a boat. He doesn’t have to pay dock fees, maintenance, or storage. He belongs to what’s appropriately called the Freedom Boat Club, which means that he can borrow a boat in any of 110 locations nationwide.

“I’ve been out all over the place,’’ said McGuire, a partner in Barrel House Z, which will serve and sell barrel-aged beers. “Sometimes I just stop in the middle of the harbor and take it all in.’’

Once the province of the wealthy, recreational boating is being opened up by a fast-growing new world of boat clubs, fractional ownership, rentals, and Airbnb-style “ship-sharing,’’ complete with mobile apps.

“People want to go boating, and these companies are giving them an opportunity to get out there in an affordable way,’’ said Carl Blackwell, president of the industry association Discover Boating.

Instead of tying them to one boat, it also lets them rent the right one for whatever purpose. McGuire, for example, takes a bow rider to commute, center-console boats to fish, and pontoon boats when he’s island-hopping with friends.

“There’s something about being on a boat and going out to an island in the harbor and sitting there for hours,’’ he said. “It’s the greatest thing in the world. It’s the most social thing there is.’’

There are an estimated 12 million registered boats in the United States, the National Marine Manufacturers Association reports. And the $36 billion recreational boating industry is going full speed ahead, with sales up nearly 9 percent last year.

This level of popularity, and advances in technology, have given way not only to the boat club concept, but to fractional ownership (Sailtime), online peer-to-peer rentals (Boatsetter, Boatbound), online charters (Open Angler), and mobile sharing apps for everything from kayaks to houseboats (GetMyBoat). There’s even a new website called Dock Skipper that lets people rent out unused dock space on lakes or in marinas.

“This is a rapidly growing segment of the marine industry,’’ said Freedom Boat Club owner John Giglio, who said his company has seen double-digit growth over the last six years. “A lot of it ties into millennials. That’s the target audience for us in a lot of markets, and they don’t want to own anything.’’

Other ship-sharing providers said around 40 percent of their customers are under 35, and 60 percent are 45 and under.

“Our sweet spot is probably 35 to 55. It’s a lot of young families with children who don’t want to be bothered with the ownership expense and hassle of a boat when they’re busy running around,’’ said Captain Matt O’Connor, general manager of Freedom Boat Club’s Greater Boston and Cape Cod operations.

The new on-the-water sharing economy is also a way for owners of those boats bobbing dockside in picturesque marinas to help cover the very, very high cost of them.

“When I saw the opportunity to offset the cost of ownership for a very expensive asset like boats, it was a no-brainer,’’ said Jaclyn Baumgarten, Boatsetter’s CEO, whose photo on the website shows her in a skipper’s hat.

A typical 21- to 24-foot powerboat costs more than $60,000 to buy, not including accessories, slip rental, insurance, maintenance, cleaning, storage, and registration ($73 in Massachusetts every two years).

The founders of GetMyBoat, returning from a sail one day, noticed all those pricy, idle boats at a marina, CIO Bryan Petro recounts.

“They saw this gigantic opportunity,’’ said Petro, whose company’s 53,000 users rent out everything from canoes to a houseboat replica of the yellow submarine to a crewed charter boat for great white shark diving off South Africa. “It’s just like Uber — you don’t have to own a car. We’re trying to do the same thing for boating.’’

Rather than resisting this, as hotels have done with Airbnb and taxi companies with Lyft and Uber, the recreational marine world has embraced this trend.

“It’s actually a good for the boating industry,’’ said Blackwell. “If you’re on the fence about buying the boat and you realize that one time a month you could rent it out, you can afford to buy the new boat rather than the used boat.’’

While borrowing a boat instead of owning one is much, much cheaper, that’s all relative. Freedom Boat Club, for example, in New England, charges about $5,000 to join and $349 a month. It costs $450 per day inshore to $1,500 offshore to hook a fishing charter through Open Angler. And about the cheapest daily rental on Boatbound around here is $125 for a fishing skiff, up to $2,100 for an 80-foot Chris-Craft Commander with a captain.

But that Commander can accommodate 65 people, and the website helpfully breaks down the cost for you: $32.30 per person. For a day on your own boat.

Even a powerboat split six ways would come to about $150 each, Petro pointed out. “That’s a nice dinner for most people, but you can have a whole day experience.’’

This at a time when open water offers an escape from crowded cityscapes, busy days, and inexorable texts, e-mail, and Instagram — and when it’s sometimes easy to forget that there’s a lake or ocean out there.

“It’s about connecting and disconnecting,’’ Blackwell said. “If you’re on the water, you’re more apt to put that phone down — because, frankly, if you drop it, you’re in trouble. I’ve seen that happen.’’

In about 100 hours of interviews with users, Baumgarten said, Boatsetter’s learned that going boating is “like a mini-vacation. You leave all your troubles on the shore.’’

There’s also a bit of ego in it, she said. “You can have a million-dollar boat for a day.’’

But what it’s really about, said Petro, “is escaping it all, hitting the water where you’re complete isolated and have natural beauty all around you.’’

He asked: “Have you really seen the city from the water? Have you slept on a boat at the marina? That’s getting away from it all.’’

A lot of users haven’t done this, Petro said. “They don’t have experience. They just want to get their feet wet.’’

He paused.

“But not too wet.’’

Jon Marcus can be reached at jon@mysecretboston.com.