Triangular aerial recognition roundel on subchaser SC 208, and on SC 323 Roundel on subchaser SC 208: 
Photograph of SC 208, courtesy of Bobbie Miller, daughter-in-law of SC 208 crewman Henry Miller. Roundel on SC 323. Photo caption: "The USS 323 in rough weather off Holyhead."
Photograph of SC 323. T. Woofenden Collection. Known examples of this roundel style: SC 208 (served at Plymouth and Queenstown, shown above in unidentified location.) SC 323 (served at Plymouth and Queenstown, shown above near Holyhead, Wales)
Another example of the triangular version, from a set of photographs in the collection of an SC 248 crewman, courtesy of Don Peteya:
