PORTLAND — Under a deal announced Thursday, a proposed ferry service linking Portland with Nova Scotia is expected to begin nightly trips out of Maine on May 1 of next year.

The agreement between the Canadian province and a team led by Eliot-based ferry operator Quest Navigation calls for Nova Scotia to invest $21 million over seven years in the company’s service to the region, and requires the ferry to comply with a daily May 1-Oct. 31 schedule. For Portland travelers, that agreed-upon itinerary will feature regular 8 p.m. departures from Maine’s largest city and arrivals in the port town of Yarmouth, N.S., the following mornings at 7 a.m.

Return trips will leave Yarmouth at 9 a.m. and reach Portland at 5 p.m.

Quest Navigation must still finalize a joint venture agreement with Singapore-based ST Marine, a shipbuilder that has constructed the ferry proposed to be used in the service, before the restoration of day trips by water to Canada becomes a certainty. That ferry, which will be christened the Nova Star, is a 528-foot-long vessel with the capacity to carry 1,250 passengers and 300 vehicles.

The ferry was initially built to take passengers across the English Channel, but is now docked in Singapore awaiting a final pact between ST Marine and Quest.

In a statement issued Thursday, Quest Navigation President and CEO Mark Amundsen showed optimism that the final hurdle in the long process of returning ferry linkage between Portland and Nova Scotia will be cleared in plenty of time to reach the May 1 start date.

“We are very pleased with the tremendous progress that we have made,” said Amundsen in a statement. “We are working to finalize the details of our joint venture, and we’re excited to start moving ‘full steam ahead’ with our plans to re-establish the Yarmouth-Portland cruise ferry service in May of 2014.”

Previous ferry service between the two locations ended in 2009 when the Nova Scotia government opted to cut off its annual subsidies for the high-speed CAT ferry, which had been running the route at a loss for three years at that point.

For the prior 35 years, ferry service connecting Portland and Nova Scotia was provided by slower vessels such as the Prince of Fundy, Bolero, Caribe, Marine Evangeline and, more recently, the Scotia Prince. Compared to the CAT, a catamaran vessel which made the commute in just more than five hours, the Scotia Prince was a monohull cruise ship which made the trip in 10-12 hours.

The Thursday announcement by Nova Scotia Economic and Rural Development Minister Graham Steele that the province will invest $21 million to restore the service does not come as a surprise. The province first pledged the money last fall when it sought bids by companies willing to run the ferry route.

The proposed Quest Navigation-ST Marine partnership — called STM Quest — ultimately won the bidding war, which placed the companies in line to collect the subsidies.

Thursday’s announcement served as a public acknowledgement of how that funding would be broken up, as well as that the new ferry operators had agreed to provincial terms such as a daily schedule. Of the $21 million, $10.5 million will go toward start-up costs, followed by $1.5 million annually over seven years for marketing.

STM Quest additionally committed to creating Nova Scotian jobs and purchasing products and services from Nova Scotian businesses.

Steele’s announcement did not specify how many jobs Quest Navigation is obligated to generate in his province or how much money the company must spend with the local businesses.

“We have a deal,” said Steele in a statement. “STM Quest has a plan to put a cruise ferry in the water in May, and the province and STM Quest have negotiated an agreement that will benefit families, local businesses and tourism operators in southwestern Nova Scotia.”

While no recent data is available on the economic impact of ferry service to Portland, the ferry’s effect on Nova Scotia has been more thoroughly documented. The Yarmouth and Shelburne, N.S., Chambers of Commerce issued a report on the ferry service’s economic benefits when The Cat runs were discontinued in 2009, while a provincial task force reviewed the subject more recently and put out a 71-page paper on it last August.

In the service’s most recent heyday, in 2002, the provincial report found that 95,000 people made their way to Nova Scotia using the Maine ferries, but that number dropped to 55,000 by 2005 and 26,000 by 2009.

The study attributes the free-fall in ridership to a number of factors, including the rise in fuel costs, diminished capacity with the departure of the larger Scotia Prince, the economic recession and the appreciation of the Canadian dollar.

That same report predicted that a ferry service restored to 2002 ridership would inject $2.9 million in annual tourism dollars in the immediate entry point of Yarmouth and $16.3 million each year across the larger province of Nova Scotia.

A healthy ferry service would create 355 jobs, worth $8 million in annual income, provincewide as well, the study predicted.

“This is the news we have been waiting for,” said Yarmouth, N.S., Mayor Pam Mood in a Thursday statement about the province’s deal with STM Quest. “The feeling here in Yarmouth and throughout the province is one of both relief and excitement.”

BDN Business Editor Whit Richardson contributed to this report.