New locks at Panama Canal (copy)

A big COSCO cargo ship that can carry about 9,500 20-foot-long containers traverses the expanded Panama Canal. Charleston is expecting an even larger ship this spring that can hold about 14,000 boxes. File/AP

As the State Ports Authority gets ready to mark its 75th anniversary Sunday, the agency that operates the Port of Charleston is about to set another milestone — the arrival of its first container ship carrying 14,000 cargo boxes, known as TEUs in maritime jargon.

"We will have a 14,000 TEU ship in May," said Jim Newsome, the SPA's  chief executive officer. "That will be the first time we've ever seen a ship of that size."

TEU is shorthand for "twenty-foot equivalent unit," an inexact measurement of the metal boxes full of goods carried by container ships. Vessels carrying 14,000 TEUs are among the largest sailing today.

Jim Newsome

Jim Newsome is president and CEO of the State Ports Authority. Provided/File

The first ship of that size to visit Charleston likely will be one operated by the Ocean Alliance — a consortium of shipping lines including COSCO, CMA CGM, Evergreen and Orient Overseas. The alliance plans to use that class of ship — called a Post Panamax vessel because it would have been too large to get through the Panama Canal before a recent expansion of the waterway — on weekly visits to Charleston.

Once a project to raise the Bayonne Bridge in New Jersey is completed later this year, Newsome said he expects the 2M Alliance, a consortium of Maersk Line and Mediterranean Shipping, will add a second weekly service to Charleston featuring a similar-size vessel. The bridge is currently too low to let Post Panamax ships access the Port of New York and New Jersey, and shipping lines have been reluctant to deploy those vessels on East Coast routes until the span is raised.

The arrival of big ships comes as the SPA is moving forward with a plan to dredge Charleston Harbor to 52 feet, giving Charleston the deepest shipping channel on the East Coast and allowing Post Panamax vessels to visit at any time, regardless of tides.

The project has been authorized by Congress and the assistant secretary of the U.S. Army recently transmitted notification to the House and Senate of the SPA's plan to enter into a project partnership agreement with the Army Corps of Engineers. Both chambers of Congress have to accept that plan for it to move forward. So far, the Senate has acknowledged and accepted the notification without issues. The House is expected to do the same.

Bayonne Bridge (copy)

The $1.3 billion Bayonne Bridge "Raise the Roadway" project will allow larger ships to pass underneath the span on their way to the Port of New York and New Jersey. File/AP

AP/Mel Evans

"In layman's terms, it sets out the funding for the project and states that we are ready to spend the money that we have," Newsome said.

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State legislators set aside $300 million toward the dredging project several years ago, and President Donald Trump is expected to include some of the federal government's $209 million share in his budget for the coming fiscal year, which starts on Oct. 1. If that happens and the Army Corps acquires the dredges it needs, the project could begin by the end of this year with completion expected sometime in 2019.

"I think the president's budget will have some funding ... I'm hopeful it will," Newsome said. "Our project is a very visible project, one of the major deep-draft navigation projects in the country today. It's a very reputable project in terms of its timeline. We really just need to get some money in there this year so we can start spending the money the state put aside in 2012."

All of this as the authority, established by the General Assembly in 1942, prepares to mark its diamond anniversary. Before that, the City of Charleston ran the port.

The SPA plans to spend about $500,000 on a print and digital marketing blitz — with the theme "Imagine What Tomorrow Holds" — that will highlight both the agency's history and its future role in driving economic development in South Carolina. Public relations firm Chernoff Newman, which has offices in Mount Pleasant, will handle the campaign, which is expected to run through June.

For Newsome, the anniversary is an opportunity to get the word out about all the SPA has accomplished, and "the exciting opportunities that lay ahead."

"We're always amazed when we go out to speak to groups and they don't really grasp the expanse of the port, what it's all about and how it relates to the economy," Newsome said. "I think we have a duty to educate the owners of the port, which are the residents of South Carolina, about what we do. We want to do a good job of telling that story."

Reach David Wren at 843-937-5550 or on Twitter at @David_Wren_