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Scupper

An opening in the side of a ship or boat, designed to allow water on deck to drain overboard.

In maritime terminology, a scupper is an essential feature of a vessel’s design, specifically created to manage water that accumulates on the deck. These openings are typically located along the edges of the deck and are connected to drainage systems that direct water overboard, preventing it from pooling on the deck, which could otherwise compromise the vessel’s stability or safety. Scuppers are particularly important in rough seas or during heavy rain when water can quickly accumulate on deck. 

The design of scuppers ensures that water is efficiently channelled away while preventing seawater from entering the vessel. They often include grates or non-return valves to stop debris from clogging the drainage system or to prevent water from flowing back onto the deck in heavy seas. On larger vessels, scuppers may be part of a more complex drainage system that includes gutters and pipes, while on smaller boats, they may be simple holes or slots cut into the bulwarks or gunwales.

Proper maintenance of scuppers is crucial for the safety of the vessel. Blocked or damaged scuppers can lead to water accumulation, which can affect the vessel’s balance, increase the risk of slipping on deck, and, in extreme cases, lead to flooding. Therefore, regular inspection and cleaning of scuppers are vital tasks in the upkeep of any seafaring vessel.

Slang or Saying

The saying ‘to scupper’ (to sabotage or ruin something) has some possible connections to the nautical term — and there are a couple of theories:

  • Naval origin theory: In naval slang, “to scupper” someone meant to kill or dispose of them, possibly by throwing them overboard through a scupper (not pleasant!). That violent origin may have extended metaphorically to mean to destroy or sink something — like an idea, plan, or project.
  • Broader metaphorical use: Since scuppers were associated with damage control and dangerous overflow (i.e., water coming onto the deck), the term might’ve picked up a more destructive or ruinous connotation over time — especially in British naval slang.