Scuppers are openings or tubes located at the edge of a boat's deck—usually through the gunwales or transom—that allow water from rain, spray, or high seas to drain overboard. They prevent water accumulation on deck, crucial for safety and preventing flooding. They are sometimes plugged to stop liquids from escaping.

Key Details About Scuppers:
Purpose: The primary role of scuppers is to clear water from the decks, keeping the vessel safe and dry.

Location: They are typically found at the lowest points on the deck, often in the corners or along the sides at the deck-hull intersection.

"Freeing Ports": In larger ships, large openings in the bulwark (the wall around the deck) are called "freeing ports" and serve the same purpose.

Etymology: The term is derived from the 15th-century Old French word escopir, which means "to spit out".

Maintenance: Clogged scuppers are hazardous as they can lead to excessive water weight, reducing stability.

Plugs: On smaller boats like kayaks, scuppers are sometimes closed with specialized scupper plugs to prevent water from entering.