Understanding Bale and Grain Capacity, Stowage Factor, Broken Stowage, Load Density, Cargo Density, Ullage, Sounding, Displacement, and Deadweight
Bale and Grain Capacity: Bale capacity refers to the total cargo space available for bags, bales, pallets, or boxed cargoes, excluding the space between frames and beams. It is slightly less than the grain capacity. On the other hand, grain capacity represents the total cargo space available for bulk cargo, including the gaps between frames and beams in the hold.
Stowage Factor: Stowage factor is a measurement that indicates the space occupied by one metric ton of cargo. For example, if the stowage factor of clinker is 1.5, it means that one tonne of clinker will occupy 1.5 cubic meters. Stowage factor is typically expressed as cubic meters per tonne (m3/tonnes) or cubic feet per tonne (ft3/tonne). It does not account for any space lost due to broken stowage.
Broken Stowage: Broken stowage refers to the space lost on a ship due to irregularly shaped cargo or an irregular hold. This includes the space lost between cargo packages. Broken stowage is expressed as a percentage. For example, if a cargo has a broken stowage of 5%, an additional 5% of the cargo volume must be allocated to account for this lost space.
Load Density: Load density refers to the maximum weight that can be safely loaded in a 1-square-meter area without causing any damage. It is specified in the ship’s stability booklet and is typically expressed in metric tons per square meter (m.t./Sq. M).
Cargo Density: Cargo density is calculated by dividing the cubage (volume) of a cargo by its weight. It provides an indication of the weight per unit volume of the cargo.
Ullage and Sounding: Ullage is the void space in a tank, measured from the top of the tank to the upper surface of the fluid. Sounding is the process of determining the depth of water in a tank or under a ship. Tanks are sounded to determine the liquid level within the tank.
Displacement and Deadweight: Displacement of a ship refers to the weight of the ship itself or the weight of the water displaced by the ship. Deadweight tonnage represents the weight of all cargo, fuel, dry provisions, supplies, etc., carried on board the ship. It is calculated by subtracting the lightweight tonnage from the displacement tonnage.
In summary, understanding bale and grain capacity, stowage factor, broken stowage, load density, cargo density, ullage, sounding, displacement, and deadweight is crucial for efficient cargo planning and management. These concepts help determine cargo space requirements, loading capacities, and overall stability during cargo operations, ensuring the safe and effective transportation of goods.