Mason was not alone

It is my understanding that the USS MASON was not alone in having a black enlisted crew during World War Two. There were at least two (and only two to the best of my knowledge) other ships which had black crews. The USS PC1124 (leastwise that's the number I remember) was the only one of the three which had an all black enlisted crew, since the USS MASON retained its white Chief Petty Officers, whereas onboards the PC1124, all of the enlisted crew were black. The PC1124 was also notable for having the first, or one of the first, black officers, Mathew Gravey join the crew; he later became the first black Admiral in the US Navy. The story of the USS PC1124 can be found in the book "Black Company" which can be found in libraries, and through the Interlibrary Loan. Another ship with a partly black crew was the Coast Guard's CGC SEA CLOUD which had a mixed race (both black and white) crew, though what the history of that ship was, I don't know.

And yes, the U.S.Navy was horribly slow in integrating. While President Truman ordered the U.S. Military to integrate in 1948, it was not until the later years of the Vietnam War (late 1960's or early 1970's) that the U.S.Navy really began integrating in a big way. Between 1948 and the late 1960's most blacks in the Navy remained in the Steward's Branch, though small numbers were allowed to enter the other branches of the Navy, but with great difficulty. According to one of my former Army NCO's, when his unit was ordered to integrate in the early 1950's (1951 or 1952 I believe), some 90% of the members of the unit were transfered out to other units, which in turn supplied members of their own units to bring the former all black Regiment back up to full strength.