Ship Design & Construction

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Ship Design & Construction

The International Convention for the Safety of Life at Sea (SOLAS), in its successive forms is generally regarded as the most important of all international treaties concerning the safety of merchant ships. The first version was adopted in 1914, in response to the Titanic disaster, the second in 1929, the third in 1948, and the fourth in 1960. Beginning in 1974, the International Maritime Organization adopted significant amendments to the Convention that regulated the basic minimum standards for the construction, equipment and operation of ships, compatible with their safety. Countries are responsible for ensuring that ships under their “flag” comply with its requirements, and a number of certificates are prescribed in the Convention as proof that this has been done. Control provisions also allow countries to inspect ships of other countries if there are clear grounds for believing that the ship and its equipment do not substantially comply with the requirements of the Convention – this procedure is known as port State control. In Canada, Transport Canada is accountable for the delivery of the Port State Control program.

The building of a ship is extremely complex and costly, especially as the asset may be operated for multiple decades in an evolving marketplace and regulatory environment. Its design must consider its purpose, its anticipated area of operation, and also anticipate the likely long-term regulatory environment. Increasingly, the design of ships is heavily focused on environmental performance to reduce its footprint, especially with respect to reducing Greenhouse Gas emissions. Autonomous ships are also being explored, and several pilot projects are already in the early stages of implementation.

Types and Sizes of Ships

The size of a ship is generally referred to in relation to its cargo capacity, or deadweight tonnage (DWT). DWT is a measure of a vessel’s weight carrying capacity and does not include the weight of the ship itself.


Ships carrying bulk cargo such as grain, potash, or coal, can also be classified according to their size. Some common terms include:

  • Handysize bulker: 15k – 39k DWT
  • Handymax bulker: 40k – 50k
  • Supramax bulker: 50k – 60k
  • Panamax bulker: 60k – 80k
  • Post Panamax bulker: 80k – 110,000 DWT
  • Capesize bulker: 160k – 210k DWT


Ships carrying bulk liquid cargo can also be classified according to their size but also by the type of product that they carry. This includes:

  • Product Tankers: This type of tanker generally carries refined products and is constructed so that it can carry many different refined products, such as gasoline, kerosene, gasoil, etc. Product tankers can be as large as 160k DWT.
  • Crude Carriers: Crude carriers are used for the carriage of crude oil from oil producing countries to refineries. Their size ranges from about 50k DWT deadweight to more than 500k DWT deadweight, which is the size of a modern Ultra Large Crude Carrier (ULCC). These vessels can load one or up to two grades of unrefined crude oil and their pumping and pipeline systems are relatively simple as opposed to Product Tankers.
  • Chemical Tankers: They are also called Parcel Tankers and vary in size from about 5k DWT to 40k DWT. Chemical tankers are mainly used to transport chemical products both organic and inorganic (toxic and/or hazardous) and at various levels of flammability. Many edible/vegetable oils including bio-fuels as well as very clean oil products are also within the carriage limitations of these ships. The are  usually required to conform to high specification requirements with extensive cleaning capabilities and carriage parameters including tank atmospheric (nitrogen), heating and cooling systems for cargo care and control.

Container Ships

These vessels are constructed to load containers only. Their holds are cellular, with vertical frames or guides where the containers are slotted. Their size is usually stated by the number of 20-foot containers a ship could carry, referred to as twenty-foot equivalent units (TEU). Container vessels range in size from as small as those with a capacity of about 500 TEU and as large as those with a capacity of about 22k TEU.

Asia Dominates Ship Construction

South Korea is the world’s largest shipbuilder, followed by China. South Korea’s “big three” shipbuilders, Hyundai Heavy Industries, Samsung Heavy Industries, and Daewoo Shipbuilding & Marine Engineering, dominate the global market for large container ships. The market share of European ship builders began to decline in the 1960s as they lost work to Japan in the same way Japan most recently lost their work to China and South Korea. Modern shipbuilding makes considerable use of prefabricated sections. Entire multi-deck segments of the hull or superstructure will be built elsewhere in the yard, transported to the building dock or slipway, then lifted into place. This is known as “block construction.” The most modern shipyards pre-install equipment, pipes, electrical cables, and any other components within the blocks, to minimize the effort needed to assemble or install components deep within the hull once it is welded together.