Container ships play a crucial role in the economy and thus form a very necessary part of the shipping trade. In order to work efficiently on a container vessel and to understand container operations, it is important for deck officers and the deck crew to have a sound knowledge about containers, including container markings, their standard dimensions and the means to identify their stowed position. Every officer and crew working on the deck must be familiar with the Bay Plan, which helps in the easy identification of containers.
Dimensions: Containers loaded on-board ships are generally 20 feet or 40 feet in length; however some vessels can also load 45’ containers. 40’ containers are designated as group A while 20’ containers are designated as group C. The heights vary from 8 feet to 8 feet 6 inches.
High cube container has a height of 9 feet 6 inches. When a high cube container is stowed below the deck, it is important to make sure that there is enough clearance between the container and the hatch cover so that the hatch cover can be closed securely.
The width of all containers is standardised at 8 feet so that containers can be stacked over each other in tiers. The duty officers must ensure that 20 foot containers are not stowed over a 40 foot container. 45 feet containers can be stowed over a standard 40 foot container as containers longer than 40 feet usually have additional support points at the 40 foot position.
courtesy: https://www.marineinsight.com/guidelines/handling-containers-on-ships-dimensions-markings-and-bay-plan/