What is ballast water used for?
Ballast water is used in the maritime industry to provide stability and balance to vessels, particularly large ships and boats. It serves several important purposes:
- Stability: Ballast water is used to improve a ship’s stability by adjusting its weight and buoyancy. Ballast water can be added or removed to ensure the ship’s stability under various conditions, such as when it is empty, partially loaded, or facing rough seas.
- Trim: Ballast water can also be used to adjust the trim of a ship. Trim refers to the longitudinal balance of the ship, ensuring that is level from front to back. Proper trim is essential for safe and efficient navigation, as it affects the ship’s handling characteristics and fuel efficiency.
- Draft: By adding or removing ballast water, a ship can adjust its draft, which is the depth of the ship below the waterline. Controlling the draft is important for navigating in shallow or restricted waterways where the depth of the water is a limiting factor.
- Compensation for cargo changes: As cargo is loaded and unloaded from a ship, its weight distribution changes. Ballast water can be used to compensate for these changes, ensuring that the ship remains stable and balanced.
While ballast water serves these critical purposes for ship stability and safety, it can also pose environmental challenges. Ballast water often contains a variety of aquatic organisms, including bacteria, algae, plankton, and even small fishes. When ships take on ballast water in one location and discharge it in another, these organisms can be transported to new ecosystems, potentially leading to the introduction of invasive species and ecological disruptions. As a result, there are international regulations and protocols, such as the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM), issued by the International Maritime Organisation (IMO) aimed at mitigating the environmental impact of ballast water discharge. These regulations require ships to treat or manage their ballast water to reduce the risk of introducing harmful species to new environments.