Jama Idle Ibrahim told the court he believed the Ashland was a merchant vessel he could hold for ransom. The ship was attacked April 10 in the Gulf of Aden.
"Today marks the first conviction in Norfolk for acts of piracy in more than 150 years," U.S. Attorney Neil MacBride said. "Modern-day pirates must be held accountable and will face severe consequences."
Ibrahim, also known as Jaamac Ciidle, pleaded guilty to attacking to plunder a vessel, engaging in an act of violence against persons on a vessel and using a firearm during a crime of violence. As part of a plea agreement, Ibrahim faces 30 years in prison.
Ibrahim was one of six Somalis who chased the Ashland and then fired on it in an attempt to seize it.