In “A Night to Remember” (1956) the author suggests that some of the more than 100 stokers laboring in the bowels of the ship were black.
A stoker who survived recalled scrambling up the ladder and seeing a black stoker slumped against a bulkhead, empty of hope, and singing to himself,
“Way down upon de Swanee ribber, far, far away.....”
Stokers were black from coal dust after they’d been working awhile, no matter what color they were when they started.