holystone

A piece of soft sandstone used for scouring the wooden decks of a ship. Smaller holystones were called "prayer books" and larger ones "Bibles," and it may have originated because the task was historically done down on ones knees, just as in prayer. In the height of its practice, a captain in the Royal Navy might call for the decks to be holystoned daily, which could take up to four grueling hours.

We are to holystone the decks from 4 o'clock in the morning until 8.

If a man should rest he is kicked in the face and bleeds on the stone, and afterwards made to wash the stone from the blood and then reported to the captain and flogged for no provocation.

—From a petition of the crew, HMS Eurydice, 24 April 1796[4]

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