As a very important contribution that propelled the shipbuilding industry worldwide, the scull (a kind of oar) was first invented in China.

Although the exact time of the scull's invention is hard to pinpoint, it is likely no later than the Han Dynasty (206BC-220AD), when there was a dictionary-like book that included the word lu (scull), explaining that the force it generated was along the ridge (the part of the ship in the water) of the ship.

The scull is similar to but larger than the oar in appearance, and is usually positioned on the stern (rear part) and the bow (front part) or the two sides of a ship, while pivots, or oarlocks, are usually placed on board the ship. The blade end touches the water, while the other end is fastened to the ship. When the scull is swayed in a certain direction, a propelling force will be produced, which will push the ship forward or backward.

An ancient saying goes, "A scull equals three oars," referring to the high efficiency of the scull. Before the scull's invention, a person could drive a boat forward by putting the oar forward into the water, pulling the oar forward (thus pushing the boat forward) before lifting the oar out the water and repeating the process. But with the scull, a person could use a rolling method (like a wheel) to move the oar in and out the water; this method reducing the need to continuously lift the entire oar up, made oaring both faster and more efficient (as less energy was needed for each thrash, or strike of water).

Apart from being a continuous propelling tool, the scull is also capable of controlling a ship's sailing direction. J. McGregor, a British scientist, therefore, believes the invention of the screw propeller was inspired by Chinese people's use of the scull. In fact, the continuously whirling blades of the screw propeller, which is widely applied today, are quite similar to the scull blade.

Author: Jessie