Commercial maritime fleets utilize seven primary vessel classifications engineered for specific freight categories: Container Ships (for standardized intermodal boxes), Bulk Carriers (for unpackaged dry goods like ores and grains), Tankers (for crude oil and liquid chemicals), General Cargo Ships (for break-bulk and miscellaneous items), Roll-on/Roll-off (RoRo) Ships (for wheeled vehicles and machinery), Refrigerated (Reefer) Ships (for temperature-sensitive perishables), and Gas Carriers (for liquefied natural or petroleum gas transport).