ro-ro
n.— «The Kaholo is a roll-on/roll-off barge—”ro-ro,” in the parlance of maritime shipping—that is far easier to load and unload than if cars and trucks had to be hoisted on and off.» —“Young Brothers gets ro-ro barge” Pacific Business News (Honolulu, Hawaii) Mar. 8, 2007. (source: Double-Tongued Dictionary)
“Ro-ro” is in the OED2, cited from 1969.