Scupper

"Scuppers" redirects here. For the children's book, see Scuppers The Sailor Dog.
Two scuppers cut into either side of this outdoor stairwell prevent water from building up and making the stairs slippery.

A scupper is an opening in the side walls of a vessel or an open-air structure, which allows water to drain instead of pooling within the bulwark or gunwales of a vessel, or within the curbing or walls of a building.

Ship's bulwark. 1. Gunwale, 2. Bulwark plating, 3. Flange, 4. Stanchion, 5. Stringer plate, 6. Stringer angle, 7. Sheerstrake. Scupper: 8. hole (with grille cover), 9. pipe, 10. outlet.

There are two main kinds of scuppers:

  1. Ships have scuppers at deck level, to allow for ocean or rainwater drain-off.
  2. Buildings with railed rooftops may have scuppers to let rainwater drain instead of pooling within the railing. Scuppers can also be placed in a parapet, for the same purpose.