When ferry service between North Station and the Seaport began a year ago, it was billed as a one-year pilot program, a test run.

Now, in year two, the Massachusetts Convention Center Authority is no longer just trying out the service. In fact, it’s doubling down.

Shannon McDermott, the MCCA’s transportation director, briefed the authority’s board on Thursday about the renewal of the privately-funded ferry service. She talked about how the agency is negotiating to buy a third vessel from NY Waterway, to augment the two it leases through boat operator Bay State Cruise Co.

As Boston buckles under the weight of economic success, congestion has become an increasing concern among employers. Bosses want their workers to be happy — and to get to work on time. Ferries are seen as one way to pull that off. But operating subsidies have proven hard to come by.

The MCCA presents a somewhat different take. This isn’t true public transit in the traditional sense. These boats, funded by private employers and landlords in the Seaport, shuttle hundreds of workers a day like clockwork between Fan Pier and Lovejoy Wharf near North Station. So far, eight companies are on board, collectively paying $2.3 million for the service this year. MCCA officials say the program is self-sustaining, with no net cost to the authority.

The boats come and go at 20-minute intervals, at both docks, during rush hours. The participating companies subsidize the service for their workers, but the general public pays $5 per ride. (About 10 percent of the tickets are purchased in this way.)

A third ferry would offer a new dynamic. The authority would have a backup when a boat is out of service. Ownership saves money and provides more control over the long run. It opens up the possibility of more frequent service, or an additional destination. A dock at Lewis Mall in East Boston, near the Maverick T station on the Blue Line, is being eyed as a possibility, although the site would need to be upgraded to accept the MCCA boats.

The MCCA had been herding workers in the Seaport for a few years, using its in-house transportation know-how to combine many of the corporate shuttles that rove the streets of the South Boston waterfront. Then the MCCA decided to go a step further, and replace its North Station shuttle buses with ferries. A development-funded dock at Lovejoy Wharf made the nearly 15-minute boat ride possible.

Maybe a parallel project could take shape at Lewis Mall in East Boston, a city-owned site. Those talks appear to be in only preliminary stages right now.

Meanwhile, the corporate funders of the MCCA ferry rave about it. Unlike driving or train options, they can set their clocks by the consistently reliable ferries.

PTC was among the early adopters, as it moved to the Seaport from Needham early last year. Danielle Hanson, the software firm’s manager of global benefits, said PTC wanted to ease the often bumpy transition from the suburbs to the city. Nearly 70 of its employees ride the boat, primarily commuters from northern suburbs.

Richard Martini, a top executive at Fan Pier developer Fallon Co., said he was initially concerned commuters would view the switch to the ferry as a disruption from the shuttle buses they used to take. But it turned out they appreciate the predictability that boat travel offers. A shuttle could get stuck in traffic, turning a 1.5-mile trip to North Station into a 30-plus-minute grind.

Alice Brown, planning director at Boston Harbor Now, said she welcomes the attention to ferry travel. She would prefer the MBTA oversee all inner-harbor routes, as it does with the Charlestown ferry. But for now she’ll salute the scrappiness of the privately-funded Seaport service: getting the job done without waiting for state subsidies.

One of the biggest knocks on the Seaport is the inadequacy of public transit. The Silver Line and Summer Street buses can do only so much. After all, South Boston is essentially a peninsula, served by often-overtaxed bridges and tunnels. The water is obviously a natural barrier. But ferries represent an effective way to turn that obstacle into an asset.