ballast

Ballast is a term for any heavy material added to provide stability, balance, or weight to a structure, vehicle, or system. It can be solid or liquid and is selected to meet the specific stability requirements of the application.

In maritime contexts, ballast refers to water or solid materials placed in ballast tanks or compartments to adjust a vessel’s trim, draft, and stability. Ships take on ballast water to compensate for cargo shifts or to lower the center of gravity during certain operations. Ballast is discharged at destination or before entry into ports. Managing ballast water is important for environmental protection, as invasive species can be transported in water, leading to international regulations and treatment requirements.

In railways, track ballast is the layer of crushed stone or similar material beneath and around railroad ties. It distributes loads from the rails, enables drainage, and helps maintain track alignment and stability under dynamic forces.

In construction and civil engineering, ballast can refer to coarse aggregate used to add weight and improve stability in foundations or structures. It may also be used in ballast mats or other weight-bearing applications to provide damping and load distribution.

In electrical engineering, a ballast is a device that limits or regulates current in lighting circuits, most commonly for discharge lamps such as fluorescent lamps. Ballasts can be electromagnetic or electronic, helping to start lamps and maintain steady light output and efficiency.

Overall, ballast serves to provide stability, control, and balance across diverse applications.