ABC’s “20/20,” which devoted last night’s show to the cruise ship tragedy in Italy a week earlier, was Friday night’s #1 show with younger viewers. The special edition covered the breaking news of the Costa Concordia disaster with reporting from Chris Cuomo in Italy and Elizabeth Vargas and Deborah Roberts in New York. In head-to-head competition with Dateline NBC in the 10pm hour, “20/20″ was ahead in Total Viewers (+31%), A25-54 (+47%) and A18-49 (+29%). During its reporting on the Costa Concordia disaster this week — including last night — ABC News has mentioned its ties to the cruise ship industry. In one of her stories about cruise ship safety Vargas said, “Even our parent company, Disney, has cruise ships.”