Sailors don’t have much in the way of sleep space on a ship. They may have berths, hammocks, or cots to lie in at night, but sleeping quarters are often cramped and uncomfortable.
For centuries, sailors at sea have relied on the utilitarian “rack.” These bunks, which are simply hammocks slung between two points, are stable and allow sailors to sleep in relative comfort despite the constant movement of a ship in rough seas. Prior to this, sailors had to rely on sacks filled with leaves, stacked straw, or bare planks. These beds were squalid and unsanitary, resulting in foul odors that could not be covered by sheets or a fresh blanket. They were also dangerous, with a fall off the bed causing serious injury or even death.
Once navies began adopting hammocks, it became common practice for sailors to use them while at sea. Compared to bunks and berths, the sides of a hammock wrap around a sleeper like a cocoon, making an inadvertent fall virtually impossible. This type of sleeping arrangement also takes up less space than traditional berths, allowing more sailors to be accommodated on the same deck.
The ability to sleep well in a rack, regardless of disruptions, is a critical skill for sailors to master. Hence, the term is part of their rich lexicon at sea, including phrases such as: “hit the rack,” “rack time” or “racking out.” This demonstrates just how important it was for sailors to be able to fall into a deep slumber while on duty.