He came aboard the "Harriet Lane" only to realize his son was near death. During the Battle of Galveston, "Harriet Lane" sank the Rebel tugboat "Neptune", leaving one-half of the two-vessel Confederate fleet lying on the bottom of the harbor. However, the Confederate gunboat circled and made a second run on "Harriet Lane". At daybreak, "Harriet Lane" was listing steeply, and a boat was dispatched from her side to the remaining Union ships to negotiate a surrender. During the negotiations, "Harriet Lane" was further damaged by fire from the Union "Owasco" under a flag of truce in an attempt to explode her magazine. The flagship "Westfield" was later exploded, and the remaining Union ships fled to New Orleans, leaving "Harriet Lane", along with a copy of the United States signal service code book in her cabin, in Confederate hands. The capture of "Harriet Lane" was an interesting episode of the Civil War, as it possibly involved the youngest combatant of the American Civil War. According to an account by a captured member of the Confederate boarding party:  Amongst the first men struck down were the gallant Captain Wainwright and Lieutenant Lee, who both fought with desperation and valor. One young son of Captain Wainwright, just ten years old, stood at the cabin door with a revolver in each hand and never ceased firing until he had expended every shot. The capture of the "Harriet Lane" involved also possibly the oldest active combatant of the Civil War. Captain Levi C. Harby of the Texas Maritime Service, 69 years old, was in command of the "Neptune", and was the last to leave that vessel after ramming the "Harriet Lane" portside. The "Neptune" was hit by Federal gunners and sank, but the water was shallow enough that Harby and his men could continue firing their guns from her deck. This distraction enabled the "Bayou City" to carry out the successful starboard attack that captured the "Harriet Lane". After a week of repairs, "Harriet Lane" was placed under the command of Captain Thomas C. Saunders and dispatched to fight the Union vessels at sea, despite lengthy legal discussions regarding the capture of the prize which had not yet drawn to a close. As a result, the ship was taken farther upriver and stripped of weapons to lighten her load. Lieutenant Joseph Nicholson Barney of the Confederate States Navy was dispatched command her and additional vessels in Galvestone, however the ship as already under command of Leon Smith, an army volunteer and steamboat captain, who had played a role in capturing the ship, having been placed in command of the ship by Major General John B. Magruder and in control of additional ships improvised as a "cottonclad fleet".