Source: MarineTraffic, 2018. Note: Port time is defined as the difference between the time the ship enters the port limits (excluding anchorages) and the time that the ship exits those limits. Irrespective of whether the ship’s visit is related to cargo operations or other types of operations (e.g. bunkering, repair, maintenance), port time includes the time prior to berthing, the time spent at berth (dwell and working times), and the time spent undocking and transiting out of port limits.
The cargoes carried by maritime transportation come into several categories, each requiring the usage of specialized ships. The two main categories are general and bulk cargo. General cargo is unitized (carried in defined load units), while bulk cargo is loose (carried in any quantity). General cargo, which can be counted, can be subdivided into three categories:
- Break Bulk. Concerns cargo that is carried in drums, bags, pallets, or boxes. Such ships are typically geared.
- Neo Bulk. Concerns cargo where each pre-packaged unit is accountable such as lumber (bundles), paper (rolls), steel, and vehicles.
- Containerized. The growth of container shipping required creating a new general cargo category where the cargo is being carried in container load units.
Bulk cargo, which can be weighted, can be divided into two categories:
- Liquid bulk. The majority of the liquid bulk carried is petroleum LNG (Liquefied Natural Gas), representing an emerging segment. Liquid bulk ships are commonly referred to as tankers.
- Dry Bulk. Concerns a wide variety of materials such as coal, iron ore, grains, bauxite, and sand.