Sea freight accounts for around 90% of global trade. Ocean freight is a less expensive method of shipping goods, but the drawback is a longer transit time. Sea freight is used quite extensively for the movement of bulk commodities such as agricultural products (wheat, maize, soya, etc.), coal, iron ore or for wet bulk products such as crude oil and petroleum. Other goods are containerised for shipping by sea. Table 2 identifies the strengths and weaknesses of sea transportation.
| Strengths | Weaknesses |
|---|---|
| Cost-effective | Long transit times |
| Suitable for large volumes | Must be supported by other modes of transport particularly if collection point or delivery point is land-locked |
| Environmentally friendly | |
| Extensive coverage |
Table 2: The Strengths and Weaknesses of Sea Transportation
There are three types of shipping companies servicing ports:
- Liner operators – vessels that carry containers sailing on fixed dates and to predetermined ports
- Charter operators – vessels that are utilised for a specific voyage
- Tanker and dry bulk operators – vessels that carry bulk cargo such as oil and grains