a bulk-dry-cargo ship for transporting coal. Self-propelled oceangoing coal carriers were developed in the mid-19th century to help supply the large amounts of coal needed for industry, power generation, and transportation.
A collier is a single-deck ship with a small freeboard. The engine room and sleeping quarters are located in the stern. Colliers are provided with equipment for the intensive ventilation of the cargo compartments, for testing the air temperature in the cargo compartments, for fire protection, and for protection against the gases released by the cargo. The size of the cargo hatches and the strength of the hull structures are calculated for the use of grab buckets in unloading. As of 1976, the deadweight tonnage of most oceangoing colliers was 2,000–20,000 tons, and the speed was 20–26 km/hour. In some self-unloading colliers, the cargo compartments are shaped like funnels, and belt conveyors located under the compartments carry the coal to a station on the deck, from which the coal is transferred to the shore.