Stuck Ship: 858-footer loaded with iron ore runs aground on Lake Superior

All recreational boaters who've ever damaged their engine props on rocks in shallow water can take heart — it also happens to professional captains of some of the biggest ships on the continent.

The 858-foot Roger Blough, carrying a load of iron ore pellets from the Duluth-Superior harbor to the lower Great Lakes, grounded on a reef in far eastern Lake Superior Friday afternoon.

The ship became stuck as it attempted to pass another vessel at the end of Whitefish Bay, where the lake narrows into the St. Mary's River.

Coast Guard officials are investigating the cause of the incident. "There is ample sea room in the area for vessels to transit," said U.S. Coast Guard Public Affairs Officer Creighton Chong. "So the fact that the lake 'bottlenecks,' there's still plenty of sea room for the vessel to maneuver."

Some of the ship's ballast tanks have ruptured, but the Coast Guard says the flooding appears to be under control. The vessel's fuel tanks have not been damaged, Chong said, and there's no sign of pollution in the water.

While cargo ships do not become grounded often, "navigating along the St. Mary's River is pretty tight and inherently dangerous," Chong said. The Coast Guard provides vessel traffic service in Sault Ste. Marie, Mich., to help ships travel the waterway safely.

All 24 crew members remain on board.

Coast Guard vessels are assessing the damage and along with the ship's owner are coming up with a plan to safely free the vessel. That will involve a process called "lightering," where the ship's cargo is moved to another vessel.

"It's going to be at least 48 hours until a plan is agreed upon," Chong said.