“Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds,” so goes the Postman’s Creed.

Then there was the winter of 2015.

While snow did keep some couriers from completing their appointed rounds, a frozen Bristol Harbor was nothing but a minor inconvenience to those who rely on the water to make a living.

From Independence Park to Poppasquash Point, Bristol Harbor spent the past two months covered with a solid sheet of ice, thick enough to support daring humans and wandering animals whose tracks dot the white expanse.

“It hasn’t been like this since 1995,” said Pat Rossi, whose family owns Prudence and Bay Islands Transport. “But the boat is running.”

The waterway between the Prudence Island Ferry landing in Bristol and the docks at Prudence Island tests the ferry captains’ navigational skills, as channel markers and buoys are low in the water due to the weight of the ice. Others are missing, having drifted from their positions. Meanwhile, ice floes as thick as eight inches compete with the ferry for the path of least resistance.

But that path doesn’t happen naturally. Before the 6:30 a.m. ferry can leave the dock to pick up passengers from the island, the ferry company launches its landing craft, a 74-foot steel barge, to break up the ice that formed overnight. After several passes, the sheet of ice becomes chunks of ice and slush, easily pushed by the bulking ferry. The landing craft then makes its way from the harbor to the island, leaving a swath of open water for the ferry to follow.

“We’ll go in at 5 a.m. and fire up the landing craft to break up the ice,” said Capt. Ethan Rossi.

The landing craft was the first vessel purchased by the ferry company, with the intent that it would be utilized by construction companies to haul supplies and equipment. While still a major part of A&R Marine Construction, the ferry service makes up the day-to-day operations.

“It turned out to be a lifesaver,” Ms. Rossi said of having the two vessels.

Because some navigational markers have been uplifted from their proper place in the harbor, the Coast Guard prohibits the ferry from night time navigation. On inclement weather days, the normally 25-minute ride from dock to dock can take up to an hour to run, as the ferry speed is reduced to half rather than risk any unforeseen dangers.

“When you get ice and wind, while you try to navigate through the ice, the wind catches you,” said Capt. Dominic Castigliego. “It gets kind of sketchy, but we’re managing all right.”

For most of the 150 or so year-round residents on Prudence Island, the ferry is their only connection to the mainland where they work, go to school, shop and tend to daily activities.

“It hasn’t really been bad,” said Margaret Bearse, an islander.

But the 20-year-old Rhode Island College student has learned that planning for the unexpected is part of living on the island.

“I’ve got plans A through Z,” Ms. Bearse said of the unknowns of getting back and forth to the island. “I have friends all over Bristol. If I miss the ferry, I have a place to stay.”

Three daily runs

And with the weather-influenced schedule change, the ferry only makes three runs a day, so Ms. Bearse catches the 7 a.m. ferry to get to her noontime class.

“It gives me time to read and do homework,” she said.

Island residents aren’t the only ones relying on the ferry service and the landing craft. According to Ms. Rossi, her company’s vessels are also at the beck and call of the Portsmouth Fire Department and harbor patrol in the event that emergency equipment needs to be shuttled from the mainland to Prudence Island.

“Their only option is us,” Ms. Rossi said.

On a typical run, taking tickets and directing vehicles on and off the ferry is deckhand Jim Murphy’s daily routine. This winter, shoveling snow has taken priority.

“I shovel my driveway at home, then spend the rest of the day shoveling snow off the deck,” he said of what’s become his daily tasks.

For safety, the steel deck and stairs need to be free of ice and snow to allow passengers and vehicles to board and disembark safely.

But despite the challenges and obstacles that the wintry anomaly has brought to the area, it also provides a unique perspective of nature’s balance between harshness and beauty.

As the sun rises over the Mt. Hope bridge, the glacier-like harbor looks like a field rather than a body of water. Hunting Eider ducks swim just beneath the slushy surface, creating lines in the ice as they seek their prey. Closer to the shore near Poppasquash, the carcasses of dead birds dot the pureness of the ice, casualties in the survival of the fittest.

Icebreaker for quahogger

But despite the harsh conditions, when the ferry leaves the dock in Bristol, that’s the signal for quahogger Zachary St. Ours to go to work.

“The ferry breaks up the ice for me,” Mr. St. Ours said.

Last week was the first time in almost two weeks that the 25-year-old was able to go to work due to the conditions. But the prospect of larger profits from winter quahogging makes it worth the effort.

“I’m popping quarters out there,” he said of the 25 cents-a-piece he gets for the shellfish he pulls up from the seabed. “I’m trying to get out there every day.”

As the ferry leaves its berth, Mr. St. Ours struggles to free his work boat from the ice that built up around it overnight. Finally breaking free with thrusts from his 150 horsepower engine, he makes his way out of Rockwell dock and out into the harbor.

On recent days, he said the ice was thick enough where he and other fisherman stood outside their boats.

“I love this,” he said of his occupation. “I own my own business. I work for myself.”

Inside the ferry’s heated wheelhouse, Capt. Castigliego and Mr. Murphy tend to the duties of shuttling passengers back-and-forth between ports, while enjoying the view outside the windows.

“There’s no more beautiful place on earth,” Mr. Murphy said.

Their efforts, even with the scheduling changes, are appreciated by the island passengers who are largely unfazed by the weather.

“They are wonderful,” David Homan said of the ferry provider’s first winter on the job. “They send two boats over to get us back and forth,” he said.

Sign of spring?

After weeks of below freezing temperatures and dodging ice floes, the Prudence and Bay Island Transport Company added a message to its customers on its website that may be a sign of spring.

“If the ice continues to melt during the week, we will reinstate the mid-day runs starting Wednesday,” the message reads.