BELFAST, Maine — Tap, tap, tap. Tap, tap, tap. Surrounded Saturday afternoon by a large crowd that had gathered at the entrance to the Allyn Street rangeway, or right-of-way, to Belfast Bay, stone artist Douglas Coffin moved around a 12,000 pound chunk of granite and carefully worked to split it by an ancient method called feather-and-wedge.

Coffin, a letter cutter by trade, had never worked on such a large stone before — and at times in the process it seemed as if the hundred or so people watching him collectively held their breath, waiting for the stone to split.

“This is wonderful,” said Helen Burns, a lifelong resident of the neighborhood, whose husband, Harry, has helped care for the city-owned right-of-way since 1958.

“It gives everybody a chance to get to the ocean,” he said.

The public art event was being held to mark the installation of the granite block on the Allyn Street rangeway, one of 17 that are owned by the city. The right-of-ways have existed since the 1700s and are intended to allow those that did not have waterfront property the right to get to the water for fishing, bird hunting or other purposes, city officials said.

Over the years, many of the rangeways were neglected and their ownership became disputed, engendering lawsuits between abutting landowners and the city.

“Not everybody’s been enthusiastic,” said City Councilor Mike Hurley. “There’s some people who discourage people from walking on the property.”

About 15 years ago, the city made a major effort to save the rangeways, he said. A resident committee began working to trace deeds to the right-of-ways and to mark them with signs. Then, about a year and a half ago, the nonprofit Waterfall Arts organization took an interest in the project and applied for grants to do a public art installation.

“We knew we wanted to have some public art that would be integrated into the site,” Waterfall Arts Creative Director Martha Piscuskas said while watching Coffin gently tap the wedges placed in holes he had drilled in the granite. “We looked at work from around the country and the world, at work that would last. Douglas’ proposal was such an elegant solution to what we’ve been looking for.”

Once the stone broke — if it broke — it would be pulled apart and set in the wide, grassy access to the bay, which shone blue and peaceful in the sunlight of the unseasonably warm November day.

Suddenly, Coffin called out that a crack had appeared. Children ran over to investigate and adults leaned closer. But still, the granite did not break and the tapping continued.

Waterfall Arts has enough money left over from the $12,000 in grants received from the NLT Foundation, the Davis Conservation Foundation and the Maine Arts Commission to have a similar public art installation on a second rangeway, Piscuskas said.

Then, the air split with shouts and an echoing boom as Coffin’s patient tapping paid off, and the granite split in two.

“It’s totally exciting,” said Rhonda Feiman. “Think about all of those molecules that have been together for millions of years. Now, we’ve opened them up to make a gateway to the ocean. It’s pretty cool.”

Afterward a crane separated the two stone halves, with some bystanders who waited to watch that, too.

“I just think it’s really interesting,” said Michelle Leavitt of Belfast. “It’s just cool to see an art project like this.”