Gijsha,
Although the Gluckauf is considered as the original "tanker", she was not the first to carry oil in bulk on ocean voyages. We have to thank Tormod Rafgard in his book "Tankers, Big Oil and Pollution Liability" for the following historical information which indicates that this first occurred some 25 years earlier.
The first full cargo of oil to cross the Atlantic was carried in the 224-ton (350 deadweight tons) brig, Elizabeth Watts. An Englishman, Mr. E.A. Sanders, owned her, and the ship sailed her first voyage from Philadelphia to
London in late 1861. The departure from the American port had difficulties. Crewmembers considered the new cargo with scepticism, and many deserted. The captain, Charles Bryant, had to resort to the local bars in Philadelphia, Pennsylvania, USA, to assemble men “willing” to take the brig to England. Despite the fact that the crew had been made up of several drunks from water -point bars, the passage went well and encouraged an increasing trade.
Two years later, Mr. Gibson of the Isle of Man took a new initiative. He built an iron hull sailing ship, Ramsey. She could carry oil in bulk and was noted for her hollow masts which, connected with the specially designed iron tanks,
served as expansion trunks. In addition, general cargo was carried on deck.
On the other side of the North Sea, Norwegian ship-owners entered the game. The first primitive tanker might possibly have been the iron schooner, Risobank, built in Inverkeithing, not far from Leith, Scotland, in 1868. The
owner, Emil Salvesen, operated an oil refinery in the little town of Mandal at the Southern tip of Norway. After some trips, however, the iron schooner disappeared with the Captain Edmund Eeg and his full crew in stormy winter weather somewhere off the Norwegian coast.
The next Norwegian effort was undertaken in cooperation with a group of French merchants in the 1870s. Gustav Conrad Hansen of Tonsberg, together with his captain, Even Tollefsen, had four sailing ships rebuilt for transportation of oil in bulk by lining the wooden hull with cement or felt. They had the sides of the holds double-boarded and sealed. One of the ships grounded in Delaware River in 1879. Another left the US with her first cargo, never to be seen again, but the concept proved reasonably satisfactory.