Crossword Dictionary

BALLAST 

Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, submarine, or other floating structure that holds water is called a ballast tank. Water should move in and out from the ballast tank to balance the ship. In a vessel that travels on the water, the ballast will remain below the water level, to counteract the effects of weight above the water level. The ballast may be redistributed in the vessel or disposed of altogether to change its effects on the movement of the vessel.

The basic concept behind the ballast tank can be seen in many forms of aquatic life, such as the blowfish or members of the argonaut group of octopus. The concept has been invented and reinvented many times by humans to serve a variety of purposes. In the fifteenth and sixteenth century, the ballast "did not consist entirely of leakage, but of urine, vomit, and various foul food leavings that lazy sailors discharged into the ballast contrary to orders, in the belief that the pumps would take care of it."

 In the nineteenth century, cargo boats returning from Europe to North America would carry quarried stone as ballast, contributing to the architectural heritage of some east coast cities (for example Montreal), where this stone was used in building. Ballast weight is also added to a race car to alter its performance. In most racing series, cars have a minimum allowable weight. Often, the actual weight of the car is lower, so ballast is used to bring it up to the minimum.