Types of Merchant Ships Merchant ships of nations engaged in commerce exist in great and growing variety. They may, however, be classified according to the type of material they carry. The main types are Oil Tankers , ore and bulk carriers, bulk and oil carriers, container ships , general cargo ships, ferries and passenger ships , and miscellaneous vessels. Tankers, carriers, and other ships. In 1986 the world merchant fleet stood at 75,266 ships totaling 404,910,267 gross tons.
Crude oil is carried in oil tankers or in bulk and oil carriers.
The hull of an oil tanker is divided into tanks that are loaded and unloaded by pumps. The size of both oil tankers and bulk carriers has increased spectacularly. In the early 1950s maximum sizes were about 46,000 deadweight tons and 25,000 deadweight tons, respectively. Today the largest tanker is about 555,000 deadweight tons, and the largest bulk carrier is just over 364,000 deadweight tons. To lessen the danger of oil spills from these tankers, the International Maritime Organization and the United States Coast Guard require that tankers be fitted with segregated ballast tanks, crude-oil washing facilities, inert gas systems, and dedicated clean ballast tanks.