PORTLAND – After a six-month lull, container shipments will once again pass through Maine’s largest seaport.

This week’s arrival of the Ossian, which will carry Maine goods to and from larger ships in Boston and Halifax, Nova Scotia, marks the port’s first container traffic since federal marshals seized the Shamrock in July in a dispute over payment of the ship’s mortgage.

The Shamrock was sold at auction in November. Its new owners plan to use it on a route between Halifax and the Caribbean.

The Ossian, which is roughly the same size as the Shamrock, has been operating between Europe and Iceland under the name Manafoss. It will be chartered by a shipping agent and operated under a contract with Hapag-Lloyd, which confirmed that the ship will begin its runs this week.

Jeffrey Monroe, Portland’s director of ports and transportation, said he had remained confident that Hapag-Lloyd eventually would find a replacement for the Shamrock.

“They remained committed to the port,” during the period after the Shamrock was seized, Monroe said. “They continued to pay the bills, so I knew the service was going to be back.”

Shippers welcomed being able to ship directly from Portland and to receive goods here rather than having the containers trucked back and forth to Boston or New York, Monroe said.

The city notified 250 of the line’s customers in Maine, northern Massachusetts, New Hampshire and Vermont to let them know the service was resuming.

“Portland had proved to be a very convenient and good port for people to operate out of,” Monroe said. “People were looking forward to coming back.”

Darcy Jordan, logistics manager for wood stove importer Jotul North America, said operating without a container ship coming into Portland has “been challenging.” She said the company has had to bring the material into New York, put it on a barge to Boston and then send a truck to Boston to bring it to Maine.