From clothes to computers, from crude oil to wine and from flowers to livestock, ships carry a diverse range of cargoes.
As the type of cargo a ship normally carries will influence its trading route and the type of ship needed to carry the cargo, a basic understanding of the types of cargoes around the world will give a better appreciation of the main trade routes of different types of ships.
Gas is one of the more unusual cargoes to move across our oceans. In its raw state, it has none of the free-flowing, easy-to-load properties of liquid cargoes, such as crude oil and grain. So, to make it easier to transport it is converted into that same liquid state by extreme cooling or pressurisation.
This process, known as liquefaction, reduces the volume of gas by a massive 600 times, and presents its own challenges for the ships that carry gas. As the gas needs to be kept in a liquid state for the entire journey, Gas Carriers must have complicated cooling or pressurisation systems on board. As a result, these highly specialised ships are often viewed as the most sophisticated of all commercial ships, costing about twice as much as an oil tanker of the same size.
The gas itself is normally propane or methane, known as LPG (link to gas in dictionary) and LNG (link to gas in dictionary) respectively and can be used in a variety of applications from environmentally-friendly fuels and refrigerant to propellant in packaged aerosols and in industrial chemical processes.
Liquid Bulk Cargo
All of us will have come across liquid bulk cargoes in everyday life in one from or another. From gasoline to fuel our cars, to fruit juices and cooking oil for consumption in the home, it’s difficult to live the lives we live today without them.
These free-flowing liquid cargoes, which also include crude oil, liquefied natural gas and chemicals, are not boxed, bagged or hand stowed. Instead, they are poured into and sucked out of large tank spaces, known as the holds, of a tanker.
This section of the industry has attracted more than its fair share of public attention over the years, as a result of high-profile incidents where crude oil has leak from tankers and polluted our seas and coastlines. But there has been much legislation passed and increasing commitment from those that carry oil cargoes to further improve this section of the industry. And importantly, there has been a substantial reduction in marine pollution over the last 15 years, especially in the amount of oil spilled into the sea, despite a massive increase in world seaborne trade.
Dry Bulk Cargo
From grains to coal and from sugar to cocoa, dry bulk cargoes cover a range of produce and raw materials that have two features in common: they are unpacked and are homogeneous. These two properties make it easier for dry bulk cargoes to be dropped or poured into the hold of a bulk carrier.
Without the estimated 3,000 m dwt of dry bulk shipping transported by sea annually, life today would be altered dramatically. Just having breakfast would be a very different event, with the ingredients of bread and cereal coming from dry bulks, as well as coffee and the sugar to sweeten it. Even the metal elements of your toaster and kettle come by sea and the coal to generate the electricity supply to power both appliances is likewise shipped in. Other dry bulk cargoes include iron ore, alumina fertilisers, scrap, sulphur and cement, as well as a large number of agricultural products for the human and animal food industry, such as rice and corn.
As the name suggests, dry bulk cargoes need to be kept dry, any moisture that finds its way into the cargo could ruin the entire load, at considerable cost to the ship owner. It may also be surprising to learn that many dry bulk cargoes are classified as ‘Dangerous Goods’ requiring special attention during loading, transportation and discharge, as they could shift during shipment, causing ship instability.