A blockae runner is a term applied to any fast-sailing ship used to penetrate a naval blockade of a harbor or strait in order to transmit valuable cargo. Blockade-runners were typically the fastest ships available and their operation was quite risky since blockading fleets would not hesitate to fire on them. However, the potential profits from a successful blockade run were tremendous, so blockade-runners typically had excellent crews. Although having modus operandi similar to that of smugglers, blockade-runners were often operated by state's navies as part of the regular fleet. Notable users of blockade runners include the Confederate States of America and Nazi Germany.