The Zoroaster, commissioned and completed in 1878, is widely considered to be the world's first successful oil tanker. It was designed by Ludvig Nobel, who notably refused to patent any part of it, leading to the design being widely studied and duplicated around the world. The tanker was built in Gothemburg, Sweden and was intended to navigate the Caspian Sea, running between Baku, Azerbaijan and Astrakhan, Russia.
The tanker featured 21 separate watertight compartments which allowed for extra buoyancy. It measued 180+ feet in length and 35+ in breadth, and could carry around 240 gross tons of kerosene at a time.