Stowage factor
Encyclopedia
In shipping, the stowage factor indicates how many cubic metres (or cubic feet) of space one metric ton of a particular type of cargo occupies in a hold of a cargo ship
. It is calculated as the ratio of the stowage
space required under normal conditions, including the stowage losses caused by the means of transportation and packaging, to the weight of the cargo. The stowage factor can be used in ship design and as a reference to evaluate the efficiency of use of the cargo space on a ship.
The stowage factor varies from one type of commodity to another — for example iron ore has a stowage factor of 0.40 (m3/t), meaning that the space needed by one ton of ore is only one sixth of that required to stow one ton of woodchips
that have a stowage factor of 2.5. This means that if a ship designed to carry woodchips is loaded with iron ore, only a small part of the hold capacity can be utilized, and a bulk carrier
designed to carry iron ore cannot be loaded to the maximum draft
with woodchips, leaving much of its deadweight tonnage
unutilized. Thus the stowage factor is taken into account in ship design when determining the size of cargo holds, and specialized ships such as ore carriers and car carriers are built for cargoes with a stowage factor that departs significantly from the average.
The stowage factor also depends on the type of packaging, being the lowest for unpackaged bulk cargo
. While most commonly used for dry bulk cargo, a stowage factor can also be calculated for liquid bulk cargo and other commodities such as containers
or cars
. Stowage factors for several types of cargo are presented in the following table.
Cargo ship
A cargo ship or freighter is any sort of ship or vessel that carries cargo, goods, and materials from one port to another. Thousands of cargo carriers ply the world's seas and oceans each year; they handle the bulk of international trade...
. It is calculated as the ratio of the stowage
Stowage
In naval architecture, stowage is the amount of room available for stowing materials aboard a ship....
space required under normal conditions, including the stowage losses caused by the means of transportation and packaging, to the weight of the cargo. The stowage factor can be used in ship design and as a reference to evaluate the efficiency of use of the cargo space on a ship.
The stowage factor varies from one type of commodity to another — for example iron ore has a stowage factor of 0.40 (m3/t), meaning that the space needed by one ton of ore is only one sixth of that required to stow one ton of woodchips
Woodchips
Woodchips are a medium-sized solid material made by cutting, or chipping, larger pieces of wood. Woodchips may be used as a biomass solid fuel. They may also be used as an organic mulch in gardening, landscaping, restoration ecology and mushroom cultivation...
that have a stowage factor of 2.5. This means that if a ship designed to carry woodchips is loaded with iron ore, only a small part of the hold capacity can be utilized, and a bulk carrier
Bulk carrier
A bulk carrier, bulk freighter, or bulker is a merchant ship specially designed to transport unpackaged bulk cargo, such as grains, coal, ore, and cement in its cargo holds. Since the first specialized bulk carrier was built in 1852, economic forces have fueled the development of these ships,...
designed to carry iron ore cannot be loaded to the maximum draft
Draft
Draft or draught may mean:* Draught beer or other beverage, served from a bulk keg or cask rather than a bottle or can-Watercraft dimensions:* Draft , distance from waterline to keel* Draft , degree of curvature in a sail...
with woodchips, leaving much of its deadweight tonnage
Deadweight tonnage
Deadweight tonnage is a measure of how much weight a ship is carrying or can safely carry. It is the sum of the weights of cargo, fuel, fresh water, ballast water, provisions, passengers, and crew...
unutilized. Thus the stowage factor is taken into account in ship design when determining the size of cargo holds, and specialized ships such as ore carriers and car carriers are built for cargoes with a stowage factor that departs significantly from the average.
The stowage factor also depends on the type of packaging, being the lowest for unpackaged bulk cargo
Bulk cargo
Bulk cargo is commodity cargo that is transported unpackaged in large quantities. This cargo is usually dropped or poured, with a spout or shovel bucket, as a liquid or as a mass of relatively small solids , into a bulk carrier ship's hold, railroad car, or tanker truck/trailer/semi-trailer body...
. While most commonly used for dry bulk cargo, a stowage factor can also be calculated for liquid bulk cargo and other commodities such as containers
Shipping container
A shipping container is a container with strength suitable to withstand shipment, storage, and handling. Shipping containers range from large reusable steel boxes used for intermodal shipments to the ubiquitous corrugated boxes...
or cars
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...
. Stowage factors for several types of cargo are presented in the following table.
| Type of cargo | Stowage factor | |
|---|---|---|
| (cu ft/t) | (m3/t) | |
| Iron ore | 14 | 0.40 |
| Grain Whole grain Whole grains are cereal grains that contain cereal germ, endosperm, and bran, in contrast to refined grains, which retain only the endosperm. Whole grains can generally be sprouted while refined grains generally will not sprout. Whole-meal products are made by grinding whole grains in order to make... (heavy) |
45 | 1.30 |
| Coal Coal Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure... |
48 | 1.40 |
| Woodchips | 90 | 2.50 |
| Containers (TEU Twenty-foot equivalent unit The twenty-foot equivalent unit is an inexact unit of cargo capacity often used to describe the capacity of container ships and container terminals... ) |
56–105 | 1.6–3.0 |
| Cars | 150 | 4.2 |
| Light crude oil Light crude oil Light crude oil is liquid petroleum that has a low density and flows freely at room temperature. It has a low viscosity, low specific gravity and high API gravity due to the presence of a high proportion of light hydrocarbon fractions. It generally has a low wax content... |
37.6 | 1.07 |
| Heavy crude oil Heavy crude oil Heavy crude oil or extra heavy crude oil is any type of crude oil which does not flow easily. It is referred to as "heavy" because its density or specific gravity is higher than that of light crude oil. Heavy crude oil has been defined as any liquid petroleum with an API gravity less than 20°.Extra... |
33.7 | 0.95 |
| Water Water Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a... |
35.3 | 1 |