Stuffing box

Compression packing is rigorously tested to ensure effective sealing in valves, pumps, agitators, and other rotary equipment.

The gland nut allows the packing material to be compressed to form a watertight seal and prevent water leaking up the shaft when the tap is turned on.

The "box" is a cylindrical assembly, typically of bronze, comprising a sleeve threaded on one end to accept adjusting and locking nuts.

A special purpose heavy-duty rubber hose attaches the stuffing box to a stern tube, also called a shaft log, that projects inward from the hull.

A sound stuffing box installation is critical to safety because failure can admit a catastrophic volume of water into the boat.

A traditional variety of shaft packing comprises a square cross-section rope made of flax or hemp impregnated with wax and lubricants.