Seamanship 2 - PDF

CABRERA, CHRIZJHAN S. BSMT II ALDEBARAN 8/13/2024 SEAMANSHIP 2 LO 1.1 Stability Terminologies 1. Definitions: Stability: A ship's ability to resist overturning when subjected to external forces. Center of Gra...

CABRERA, CHRIZJHAN S. BSMT II ALDEBARAN 8/13/2024 SEAMANSHIP 2 LO 1.1 Stability Terminologies 1. Definitions: Stability: A ship's ability to resist overturning when subjected to external forces. Center of Gravity (CG): The point where an object's entire weight is considered concentrated. Center of Buoyancy (CB): The centroid of the submerged volume of a floating object. Vertical CG: The CG's position in relation to the waterline. Longitudinal CG: The CG's position along the ship's length. Transverse CG: The CG's position across the ship's breadth. Heeling: The tilting of a ship to one side due to external forces. Listing: The permanent tilting of a ship due to uneven weight distribution. Stability Moment/Righting Moment: The force that restores a heeled ship to its upright position. Stable Equilibrium: A ship returns to its upright position after being heeled. Neutral Equilibrium: A ship remains in any position after being heeled. Unstable Equilibrium: A ship continues to heel after being disturbed. Righting Lever (GZ): The perpendicular distance between the CG and the CB when a ship is heeled. Metacenter (M): The point of intersection of the vertical lines through successive CB positions. Weight Displacement: The weight of water displaced by a floating object. Density of Fresh Water (FW): The mass of a unit volume of fresh water. Density of Sea Water (SW): The mass of a unit volume of seawater. Specific Gravity of FW: The ratio of the density of a substance to the density of fresh water. Specific Gravity of SW: The ratio of the density of a substance to the density of seawater. Lightship: A ship without cargo, fuel, or passengers. Loaded Displacement: The weight of a ship and its contents. Deadweight: The maximum weight a ship can carry. Payload: The weight of cargo and passengers a ship can carry. Gross Tonnage: A ship's total internal volume. Net Tonnage: A ship's available cargo volume. LO 1.2 Archimedes' Principle  Archimedes' Principle: When an object is placed in a fluid, it displaces a volume of fluid equal to its own volume. The weight of this displaced fluid exerts an upward buoyant force on the object, which is equal to the weight of the object if it floats.  Floating vs. Sinking: An object floats if its weight is less than or equal to the buoyant force acting on it. It sinks if its weight is greater than the buoyant force.  Steel Ship Floating: A steel ship floats because its overall density (including the air inside) is less than the density of seawater. The ship's shape and size are designed to displace a volume of water equal to its weight, creating sufficient buoyancy.