Ship Stability and Flooding Terminology

Key Concepts of Ship Stability and Flooding

• Righting Arm: The distance between the gravity center and the buoyancy center, crucial for a ship's stability.

• GZ Area: The area under the curve representing the energy required to return a ship to an upright position after listing.

• Watertight Bulkhead: A partition within the ship designed to contain floodwater to one section, enhancing the vessel's safety during flooding.

• Heel Angle: The angle of inclination of the ship from the vertical. Instability occurs if the heel angle exceeds specific limits.

• Freeboard: The vertical distance from the waterline to the deck of the ship, which must be monitored for post-flood safety.

• Draught: The maximum submerged depth of a ship after flooding has occurred.

• Progressive Flooding: The spread of floodwater through unsealed compartments, leading to increasing instability.

• Damage Stability: The ability of a ship to remain safe and operational after damage to the hull.

• Simulation: Digital tools used to analyze how a ship behaves post-flood, predicting stability and righting capacity.

• Righting Moment: The force that resists heeling and helps restore the ship to an upright position.

• Loss of Stability: A major risk associated with uncontrolled flooding, potentially leading to capsizing.

• Upright Position: The necessary orientation a ship must maintain post-damage for stability and safety.

• Counter-Flooding: A method to balance the ship's trim or heel by strategically introducing water into selected tanks.

• Bilge Pump: A device utilized to remove floodwater from the ship, helping maintain stability.

• Dewatering: The mechanical removal of floodwater to maintain vessel safety.

• Watertight Integrity: The structural capacity of the ship to prevent floodwater from entering undamaged areas.

• GZ Curve: A curve used to evaluate the righting ability of a ship after sustaining damage; it plots the righting arm at various angles.

• SOLAS: The international convention known as Safety of Life at Sea that sets regulations for ship safety, including construction standards, subdivision, and stability measures.

• Excessive Heel: A condition indicating compromised stability, where the angle of heel exceeds safe limits, risking capsizing.

• Watertight Door: A door installed to restrict the movement of floodwater between compartments, enhancing safety in the event of flooding.

• Residual Stability: The stability that a ship retains after experiencing flooding, crucial for assessing safety post-damage.