Water must not flow into the boat through the scuppers, even in rough seas.
A scupper is best known as a maritime term that refers to an opening cutting through a ship’s bulwarks that allows water from the ship’s deck to flow out to sea. Virtually all ships, as well as boats large enough to have decks above the waterline, are made with some form of scuppers. This often includes flap or ball designs that allow water to flow off the deck but not back into the ship if the scupper opening dips below the waterline in high seas or rough water.
The word embalming also refers to a groove or opening in the parapet or gravel jamb of a level roof that allows rain or melting snow to drain off the roof. This can help prevent leaks or structural damage to the building below. Sometimes scuppers are connected directly to rain gutters and downspouts. In other cases, they extend beyond the surface of the exterior wall, creating a flow of water away from the building.
Generally, a scupper can be any opening that allows water or other fluids captured in a containment vessel at one level to flow out into a lower vessel or body of water. In many environments, they are part of projects known as water-in-transit systems. This phrase refers to a system where water flows from one level to another for decorative or functional purposes.
Many scupper designs include some form of conductor head – the structure where water or some other type of fluid is collected – and a dike or spout – the passage through or over which the fluid flows and is transmitted to a lower level. Scuppers can be massive structures, such as the overflow channels used in reservoirs and dams to prevent flooding, or extremely minute, such as the chemical reservoir systems used in the manufacture of pharmaceuticals. Additionally, scuppers are commonly used on bridges and highways to prevent structural damage and to drive standing water away from busy roads.
Scuppers of various types are also used in decorative applications such as swimming pools, fountains, decorative drinking fountains and reflecting ponds, where water moves in transit from one level to another. The size, shape and materials of these scuppers are often designed to match the look and sound of moving water to create specific architectural and design effects. Bags can be made from a variety of materials, including stainless steel, plastic, polymers, polyvinyl chloride (PVC), bronze, copper, sheet metal, marble, and other types of stone.