In our everyday language, we often use sayings without really knowing where they originated. Sayings such as “to swing a cat” or “down the hatch” or “break the ice”. These three have something in common: They all began life as naval slang.
The first, “to swing a cat,” has a rather gruesome beginning: It refers to the cat-o’-nine-tails, a whip made up of nine knotted cords roughly 75 cm long that was designed by the British Royal Navy to inflict severe pain and lacerate the skin. It was used in flogging for anything from drunkenness to mutinous talk to stealing. It was known as a “cat,” and obviously they needed room to swing it, to get the full effect. Today it merely refers to the size of a room or space as being “too small to swing a cat”.
“Down the hatch” is more straightforward: The hatch was the covering of the hatchway on a ship, an opening in the deck which allowed vertical access into the hold for loading cargo. It means the act of drinking in particular, the mouth being the “hatch”.
“To break the ice” means to remove the invisible social barriers between strangers to ease conversation and social contact. It comes from the specialized ships called “ice breakers,” which were designed to plow through icy waters, making the passage of other vessels possible. Without such a ship, arctic expeditions could find themselves frozen in, land-locked by shifting ice sheets.
For many more sayings relating to naval history, check out “Not Enough Room to Swing a Cat” – Naval Slang and its Everyday Usage” by Martin Robson.