Massport hopes to open Boston Harbor to larger container ships this fall, but not Ever Given large

Massport hopes to formally open an expanded, "Big Ship Ready" Conley Terminal this fall, after $850 million and several years' worth of expansion work that has included dredging a deeper ship channel through Boston Harbor and installing new, bigger cranes to unload containers from the largest ships that can traverse the Panama Canal.

But even with all that work, the Evergreen Ever Given wouldn't be able to dock at the South Boston facility, now that it's been freed - it's just too big.

A $350-million dredging project paid for by Massport, the US Army Corps of Engineers and the state, the bulk of which finished in December, deepened the main shipping channel through the harbor into the Reserved Channel from 40 to 47 feet (the project was delayed when the Corps and Massport sued the MWRA and Eversource over the cross-harbor conduit that powers the Deer Island sewage treatment plant, which a Boston Edison contractor had failed to bury deep enough under the harbor bottom).

But fully loaded, the Ever Given has a draft of 47 feet, 7 inches.

The three new cranes Massport will be installing - so big Massport had to build a new berth for them away from the current berths because otherwise they might have caused a potential problem for planes landing at Logan - are designed to handle ships with a maximum capacity of 14,000 TEU - with one TEU being roughly equivalent to one 20-foot-long shipping container.

That's good enough for ships coming through the Panama Canal these days, and a significant increase over the roughly 8,000-TEU vessels the terminal can now unload, but the Ever Given has a capacity of 20,124 TEU.

Also, the new berth is 1,250 feet long - while the Ever Given is 1,312 ft, 2 inches long.

Still, even if the Ever Given can't dock here, its owner, Evergreen, has smaller ships that already dock at the Conley.