Three new cargo cranes will let Massport handle much bigger container ships

They’re part of an $850 million project that includes dredging the main shipping channel and expanding Conley Terminal in South Boston

The newest ship to dock at Conley Terminal in South Boston is unloading some unusual cargo: three giant cranes that tower above the Reserved Channel.

The Zhen Hua 15 cruised into the Inner Harbor Tuesday morning, bearing two 205-foot-tall cranes and one 145-foot crane. All of them are taller than the six 135-foot -high cargo cranes the Massachusetts Port Authority uses today at Conley. (One of the new cranes is smaller than the other two because of its proximity to flight paths at nearby Logan Airport.)

These three cranes are integral in Massport’s multiyear effort to better accommodate much larger container ships — an effort that includes dredging the harbor’s main shipping channel and a new berth at the expanded, 30-acre Conley Terminal.

Massport’s harbor work, costing up to $850 million, is partially funded by state and federal grants. The dredging project will make the channel seven feet deeper, dropping it to 47 feet below the surface, and be complete sometime in 2022.

Union longshoreman Kristy Cataloni poses in front of the Zhen Hua 15.Lane Turner/Globe Staff

Built in Shanghai and shipped here by the manufacturer, ZPMC, the new cranes were originally expected to cross the Pacific Ocean and pass through the Panama Canal. Instead, the Zhen Hua 15′s 10-week journey took it west across the Atlantic, after rounding Africa’s Cape of Good Hope. Massport officials say the cranes were constructed in China because that’s where nearly all of these types of cranes are made; ZPMC is the market’s dominant manufacturer.

It will take a week to unload and move them into position at the new Conley berth, via a temporary rail system set up for the job. Then they’ll need to be commissioned, a process that involves testing, inspections and training, before they can be put to use, likely by sometime in the fall.

Crew members watch as the Zhen Hua 15 docks at the Paul W. Conley Container Terminal in Boston Harbor. The Chinese characters seen on the ship read “an chuan di yi," or “safety first.” Lane Turner/Globe Staff

The Zhen Hua 15 enters the Reserved Channel to dock at the Conley Container Terminal.Lane Turner/Globe Staff