SAVANNAH, Ga. (AP) — A U.S. Coast Guard analysis found a cargo ship departing a Georgia seaport overturned because of unstable loading that left its center of gravity too high.

A naval architect from the Coast Guard’s Marine Safety Center testified Tuesday that the Golden Ray didn’t fill its ballast tanks enough to offset the weight of 4,200 vehicles in the cargo decks above.

Lt. Ian Oviatt told investigators at a public hearing in Brunswick, Georgia, that the ship’s crew had jettisoned roughly 1,500 metric tons of ballast water on a prior voyage.

He said that raised the ship’s center of gravity, leaving it susceptible to rolling over.