Self-discharging bulker (SD)

A self-discharging bulker carries an onboard conveyor-and-elevator system that discharges cargo through a boom without shore cranes or grabs, at rates of several thousand tonnes per hour. Cargo flows from hopper-shaped holds onto belt conveyors below the tank top, up an elevator or inclined belt, and out over a slewing boom to the quay or another vessel. The arrangement suits high-frequency aggregate, coal, gypsum, salt, and limestone trades where fast turnaround at minimally equipped terminals matters more than maximum deadweight. The conveyor machinery costs cargo cubic and capital, so self-dischargers are common in coastal and Great Lakes trades rather than long-haul deep-sea ore and grain runs.