Pennsylvania, 1861. Oil is drilled and poured into barrels, which are to be loaded into the whaler Elizabeth Watts. Her captain is warned of the dangers from powerful gases that can escape from the oil. The first cargo is unloaded in England.

1869. Shippers experiment with putting oil in metal tanks to prevent the escape of gas, and try different arrangements. They also investigate new ship designs, such as a steam ship with the engine aft and the rest of the hull transformed into a compartmented tank.

1886. The SS Gluckauf is designed with an additional deck and safety cavities for the gas. When the hold is filled, the gas is cleared out with steam and air.

1890. The size of tankers is increased, though this creates problems that they will not be able to berth in many existing harbours.

1903. To resolve the problem whereby increasing the tanker length puts too much strain on the hull, the SS Narragansett has its engine amidship. Subsequent designs include the engine returning aft and the hull being built lengthways with struts placed athwart. Larger and larger tankers can now be built, and similar designs can be used for other big ships, such as whalers.