(NewsNation) — Evergreen Marine Corp, owner of the 117,000-ton cargo ship stuck in the Chesapeake Bay, has announced it’s enacting a maritime practice called General Average. That means anyone with cargo on board is going to be responsible for a portion of the cost to salvage it, Sal Mercogliano, an associate history professor with Campbell University, told NewsNation’s “Prime.”

Right now, it’s Evergreen and its insurance company paying for efforts to free the ship, which is called the Ever Forward. It’s unknown, now, how much it is going to cost, Mercogliano said.

“It really depends on the scope and scale,” he said. “As of this period, we’ve never had to see a major container ship have to offload containers at anchor like this. So this is really unfathomable waters here for us.”

Past rescues of cargo ships have cost almost $1 billion. But Mercogliano said rescuing the Ever Forward won’t come anywhere close to that.

It was a simple wrong turn in the Chesapeake Bay that led the ship into 24-foot waters and created the precarious situation. The longer the ship sits immobile, the greater the chance of damage from storms or other causes.

But it isn’t easy to set the ship free: the cargo has to be unloaded with great care to avoid putting too much stress on the ship, which needs to be kept upright.

On Saturday, Mercagliano said, people have started taking containers off the vessel.

“It’s a slow process,” Mercagliano said. “They’re moving about one container every 10 minutes. The hope is over the next week to 10 days to take off about 550 containers, remove some ballast from the vessel.”

According to Axios, Evergreen Marine Corp. is also the owner of the Ever Given, a ship that got stuck in the Suez Canal last year.

“One of the big issues here is not so much Evergreen, but really the growth and size of these vessels,” Mercagliano said.

Because of supply chain issues, where there’s a large demand for goods, bigger ships are more cost-effective, Mercagliano said.