On the night of November 7, 1972, as the African Neptune was leaving the Port of Brunswick, it failed to properly align with the opening and impacted the bridge roughly 250 ft (80 m) south of the vertical-lift section.

Later investigations by the United States Coast Guard and the National Transportation Safety Board concluded that the misalignment had been caused by the helmsman, who had incorrectly entered in rudder directions given by the pilot.

The helmsman's mistakes were noticed by a mate aboard the ship, but not before the vessel had reached a point on the river where a full stop was impossible.

Following the incident, safety measures were put in place to prevent automobiles from being present on the bridge any time the vertical-lift span was open.

[7][3] Situated roughly 1.5 mi (2.4 km) south of downtown Brunswick,[5] it carried U.S. Route 17,[7][3] a major north–south thoroughfare for both the eastern portion of Glynn County and the East Coast of the United States at large.

[4][8] While the main portion of the bridge stood only about 50 feet (15 m) to 80 ft (24 m) above the surface of the river,[7][8] it featured a vertical-lift section to allow for larger oceangoing ships to access the Port of Brunswick.

[3][4][9] At around 11 p.m. EST on November 6, 1972, the ship arrived at the opening of the channel leading to the port, but because of the bridge's reputation, Frank Stanejko, the sea captain of the African Neptune, decided to wait until the next morning to begin the 15 mi (24 km) journey from the Atlantic Ocean to the docks.

[6] Due to heavy rain,[2] the ship was not cleared to leave the port until 9:36 p.m. on November 7,[6] a Tuesday night,[3] during a period of high tide.

[6] A tugboat assisted the African Neptune out of the dock,[4] after which it maneuvered under its own power out of the port area and around several barges that were moored in the river.

[note 2] Ten motor vehicles, consisting of 8 cars and two semi-trailer trucks,[13] and 24 people fell into the river,[2][7][12] which at that point had a depth of about 30 feet (10 m).

[11] Immediately following the collapse, crewmembers on the African Neptune began to throw lifebuoys into the river and deployed lifeboats in order to rescue individuals who had fallen from the bridge.

[12][note 3] Immediately following the collapse, the port was closed overnight and the African Neptune was led by two tugboats to a dock for temporary repairs.

[2][11] Prior to leaving, Georgia Governor Jimmy Carter came to Brunswick to inspect the damage and talk to some of the ship's crew.

[12][2] Search and rescue operations continued into the next morning, though no additional survivors were found,[11] and crews began to collect debris out of the river that same day.

[4] However, in their final reports issued in May 1974,[3] the investigations revealed that the allision (a nautical term for a collision between a moving ship and a stationary object) had been the result of the helmsman incorrectly entering the pilot's orders.

[14] Thus, according to the NTSB, at the time that the helmsman was incorrectly applying orders, neither the shipmaster, the pilots, nor the mate, were monitoring the input with enough frequency to identify the error prior to the "point of no return".