The Cross-Bay Ferry sailed into its third season this weekend with strong support from political leaders in Tampa Bay.

“The return on investment is incredible,” Hillsborough County Commissioner Sandy Murman said recently, echoing other local officials, as she voted to contribute $150,000 toward the popular new service. “This is a small amount of money for the number of riders."

But while the total investment by local governments is relatively low, the ferry looks like less of a bargain when measured by what it costs to transport each rider across the bay.

Taxpayers spent $34.27 to cover each ride a person took on the ferry during its six-month pilot season in 2016-17. That number dropped to $14.23 per boarding during its second season, but it was still much higher than the subsidies local governments pay for other modes of public transportation.

Hillsborough county’s buses operate at just over $6 per passenger trip, while the operating cost for Pinellas buses and Tampa’s TECO Line Streetcar are about $5 per boarding.

Supporters of the ferry, like the mayors of Tampa and St. Petersburg, say its benefits make the extra subsidy worthwhile: Residents travel between the two cities, spending money and contributing to the economy; it makes the region more attractive to tourists; the 50-minute ride between St. Petersburg and Tampa is a comfortable experience that can include sunsets and dolphin sightings; and it’s paving the way for a permanent service between multiple ports.

“I know that’s not exactly tangible, but those were the things that were important to me when I voted for it,” St. Petersburg City Council Member Darden Rice said. “Can I look a taxpayer in the eye and say this a good investment overall? I feel a very strong yes.”

RELATED: New focus on weekend trips has passengers flocking to the Cross-Bay Ferry

The Tampa Bay Times collected data from more than 15 transit agencies and analyzed operating costs, ridership and cost per boarding for each of those projects to see how the Cross-Bay Ferry compared. The per-boarding measurement is commonly used in the transportation industry and tracked in the National Transit Database.

While the ferry’s per-passenger cost to local governments was nearly three times higher than local buses and the Tampa streetcar, it was two to six times more expensive per ride compared to transit modes such as light rail and special bus lanes.

Those numbers are based on each agency’s operational costs — everything from the drivers to vehicle maintenance to the share of overhead that covers printers and computer software. They do not include capital costs, such as buying right-of-way, building stations and purchasing vehicles.

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Tampa Bay’s first potential foray into dedicated transit service lies with the Central Avenue Bus Rapid Transit project, which would connect downtown St. Petersburg with the beaches. Estimates submitted to the Federal Transit Authority project a per-person operating cost of about $3.15 per trip.

Even if the transit authority’s ridership estimate of 1.3 million passenger trips a year is inflated and the new route only sees a quarter of those, the proposed project would still receive a lower subsidy per ride than the ferry.

Ed Turanchik, a legal representative for the ferry’s operator, HMS Ferries, said it’s unfair and misleading to compare the cost to operate other transit systems with the annual amount paid for the ferry.

Because the ferry operates in a public-private partnership, its numbers are not as easy to parse as the costs to build and run a public transit option.

For example, the four contributing Tampa Bay governments — Tampa, St. Petersburg, Hillsborough and Pinellas — do not own any boats. Instead, they must pay a fee every year to lease the boat from HMS Ferries. That number is wrapped into the repeating, annual cost from taxpayers.

“It’s the most expensive way you could possibly provide service,” Hillsborough Commissioner Pat Kemp said. “If you rent a car for a month instead of owning a car, you’ll be paying a lot more,"

Operating cost per passenger trip is just one way to evaluate a transit system. The National Transit Database also tracks numbers such as cost per hour and the cost to transport one passenger one mile.

The ferry is much more competitive on the latter statistic, because all potential 149 passengers on the boat are traveling about 20 miles across the bay for every trip. A bus, by comparison, has riders getting on and off at different stops along the route.

RELATED: Tampa Bay has one of the worst public transit systems in America. Here’s why.

No matter what metric is chosen, supporters of the ferry expect it to become more competitive with time. St. Petersburg Mayor Rick Kriseman, Rice and others said they believe the ferry’s cost per passenger trip will go down in future seasons, especially as more people learn about it.

Ridership between the first two seasons grew nearly 30 percent, with people making more than 52,500 trips last season. That number is expected to exceed 60,000 this year.

“My dream is to expand it even further than that and have other ferry transit stops and have more boats running and be able to use more commuter routes,” said Hillsborough County Commissioner Mariella Smith.

Ferry supporters say permanent service would be much less expensive, with one proposal requiring local governments to pay only capital costs and HMS Ferries taking on all operating costs. Under that vision, four boats would run between South Hillsborough County and MacDill Air Force Base on weekdays and loop in St. Petersburg and Tampa on nights and weekends.

“In order to make this a permanent service, we’ve got to be able to have some data to show that people like it and that they’ll use it,” Pinellas County Commissioner Janet Long said.

Long said the seasonal service, which comes at a higher rate, is an investment in the future by building ridership and helping change the area’s car-dependent culture.

But Hillsborough County Commissioners have repeatedly tabled a deal for permanent service with MacDill Air Force Base, where local governments would own the fleet. Instead, they voted to move any decisions about the project to the Hillsborough Area Regional Transit Authority.

RELATED: The agencies that run Hillsborough’s buses will also run its ferries

That leaves Tampa Bay in a situation where it must pay about $750,000 each year to rent and run the boat five days a week for six months. This year, the boat will make 15 roundtrip sailings a week. In May, when it sails back to Massachusetts, taxpayers here will foot the bill.

The agreement with HMS Ferries is not structured in a way to help local governments get a return on their investment early on. Other transit operators are able to use money from fare revenue to bring down the operating cost per each individual trip.

Under the current agreement, HMS Ferries receives the first $400,000 of revenue, half of which goes toward expenses. Last season, the ferry earned about $294,000. If a future season passes that threshold, the local governments and HMS would split the additional money 50-50.

Most of the Cross-Bay Ferry’s ridership comes from people looking for fun, not trying to get to work. Rider numbers increased after organizers cut morning commute trips and focused on nights and weekends, helping people get to Tampa Bay Lightning and Rays games, date nights or restaurants across the bay.

The focus on entertainment over commuting frustrates Pinellas County Commissioner Kathleen Peters, who was one of only two elected officials to vote against paying for the third and fourth years of service. Peters said the subsidy is too high, especially for something that doesn’t help get cars off Pinellas roads.

“Sure, who doesn’t want to take a nice boat ride?” Peters said. “I’m not saying it’s a bad thing. I’m saying the poor people of Pinellas shouldn’t be subsidizing the wealthy for their entertainment."

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Tampa Bay transit: comparing costs

One way to compare forms of transit is by operating cost per boarding. These are the most recent numbers available.

Cross-Bay Ferry: $14.23

Hillsborough bus service: $6.17

Tampa streetcar: $5.21

Pinellas bus service: $4.94

*Pinellas bus rapid transit: $3.16

* Based on projected operating and ridership costs for 2022. Project is still seeking approval.