Air Draft & Channel Depths

Air draft potentially limits port capacity, especially as increasingly larger vessels come into service. These restrictions may not affect all terminals in a port. For example, some ports might have terminals with no air draft restrictions (e.g., the container terminals at the Port of Virginia) because no bridges cross their navigation channels. The table below shows the air drafts by limiting bridges for select ports, and the online Port Profiles show what, if any, air draft or channel depth restrictions exist within the port vicinity.
Air draft restrictions may be eliminated as bridges are either raised or replaced. Several ports have constructed new bridges (e.g., the new Gerald Desmond Bridge at the port of Long Beach, which opened in 2020)[1] or elevated existing bridges (e.g., the Bayonne Bridge at the port of New York/New Jersey, which was completed in 2019).[2] The higher the bridge, the more stacked containers that can pass under (e.g., 8-foot tall containers can reach a combined height of 144 feet when stacked 18 high aboard a megaship’s cargo deck).
Air Drafts by Limiting Bridge for Select Container Ports: 2020

Channel depths can limit the size of vessels able to call at a port. The Pacific coast ports with their natural harbors, such as the ports of Long Beach and Los Angeles, have the deepest channels. The Mississippi River ports of Cincinnati-Northern Kentucky, Huntington, Pittsburgh, and St. Louis have the shallowest channels. Even if a port’s minimum channel depth allows for megaships, the individual marine terminals within the port vicinity may not have the minimum depth alongside to handle them.
Footnotes
[1] Port of Long Beach, The Gerald Desmond Bridge Replacement Project, available at https://newgdbridge.com/ as of December 2021.
[2] The Port Authority of New York and New Jersey, Navigational Clearance Project, available at https://old.panynj.gov/ as of December 2021.