• Commercial ships are now being allowed back into a Baltimore port shipping channel to remove debris from the Francis Scott Key Bridge collapse.
• The Coast Guard is approving each ship on a case-by-case basis with strict vessel limits.
• It remains unclear how long it will be before the Port of Baltimore opens again to containership traffic, and ocean carriers stressed that containerships are not part of the recent activity.

Coast Guard officials tell CNBC the secondary channel that is being created in the southwest channel of the Port of Baltimore will only welcome commercial vessels that are cleared by the Coast Guard in the removal of debris.

"The vessels will be decided on a case-by-case basis," said Carmen Caver, Coast Guard spokesperson. "The size of these vessels are general work boats. Not the large containerships."

The size of the commercial vessels that will be allowed into the new channel is remarkably smaller, at 96 feet in length, compared to the 984-foot-long Dali, the vessel that struck the Francis Scott Key Bridge after losing navigational control and destroyed the key piece of infrastructure.

The new ship channel will be limited to a vessel's draft, which is the minimum amount of water required for a vessel to traverse the waterway without the bottom of the boat touching.

The draft for the select commercial work vessels that will be permitted by the Coast Guard to help in the removal of Key Bridge debris is 10 feet. By comparison, cruise ships have a draft of 22-26 feet, and the mid-size container vessel Dali — and the larger "mega ships" which carry over 20,000 containers —have a draft of 52 feet.

Based on a review of AIS data from MarineTraffic, there have been almost 1,000 containership arrivals at Baltimore port since January 2022, with an average TEU (container capacity) of 7,039, according to Nikos Pothitakis, Kpler spokesman. The biggest container ship that arrived at the port during this period was the Ever Max, which visited the port twice in 2023 and once in early 2024.

Major ocean freight companies made clear there is no connection between the debris removal effort and typical commercial ship traffic. In an update to clients, Maersk said that the "controlling depth of 11 feet" of the alternate channel would not be deep enough to accommodate the oceangoing container vessels that Maersk and other carriers use to call upon Baltimore and other U.S. East coast ports. Maersk is the integrated carrier that chartered the Dali, and it has continued to service diverted client's containers whereas competitors have declared they are terminating container pickup services at diverted ports.

Aaron Roth, retired Coast Guard captain and Chertoff Group principal, tells CNBC while he cannot predict when the channel will be clear for containerships, the creation of the channel is essential to create safe navigation for work vessels around the Dali.

The extent of the debris underwater and the area of damage is still under assessment, and will influence the timeline as to when the channel will be safe for the movement of containerships and bulk vessels.

Roth said there will be one tell-tale sign of when the channel is ready to open.

"Once you see plans of moving the Dali away from the port, that's when you know the channel is ready to be open," Roth said. "In the meantime, just like we saw with the Red Sea, the system will adjust. The economy knows best and the economy will absorb it," he added.

Correction: The cargo ship Dali is just under 1,000 feet long. An earlier version misstated its length.