Answer:
Blockade runners were/are ships designed for clandestine tasks such as running the blockade- a legal ban on ship traffic which is laid down by Naval vessels ( in some cases the Coast Guard might assist in preventing blockade running) the were used widely in the Civil War by the Confederates. Blockade Runners were also used during the Diaspora following the Russian revolution and B/R traffic operated in both directions in the Russian Civil War ( which followed Revolution). There is some evidence a White Russian Blockade runner blew up in New York Harbor in the late twenties. three crewmen survived and they turned out to be Russian aliens. I do not know how the case was resolved after they recovered from their injuries. They may have applied for Political asylum. a Good action adventure movie could be done on the White Russian Blockade runners which may have included submarines and aircraft as well as conventional ships. Ship ahoy, Comrade, and mind that siphon manifold- Take her down- To siphon depth- Coast Guard cutters in visual range. ring ring. down we go.