At 0400 on 17 June 1863, the powerful Confederate ironclad Atlanta steamed from the Wilmington River into Georgia’s Wassaw Sound to attack ships of the Union South Atlantic Blockading Squadron. Barring her way were two U.S. Navy Passaic -class monitors, the Weehawken and Nahant , each armed with one XV-inch and one XI-inch Dahlgren shell gun and under the overall command of Captain John Rodgers Jr. The casemated Atlanta , captained by Commander John Webb, mounted four Brooke rifled guns: two 6.4-inchers in broadsides and two 7-inchers in pivot mounts capable of firing to either side. She also had a bow-mounted percussion spar torpedo.
Webb made straight for the leading monitor, the Weehawken , intending to use his ship’s torpedo. Unfortunately for the Confederates, in so doing the Atlanta veered from the channel and grounded. She then opened fire, getting off six shots, all of which missed the Union ships. On board the approaching Weehawken , Rodgers withheld fire until the monitor was only about 300 yards distant, at which point her XV-inch Dahlgren unleashed a 400-pound projectile that obliquely struck the Atlanta ’s casemate.