SC 239 was commissioned at New York on 20 March, 1918, and served in the 5th Naval District (Norfolk).
First photo: SC 239 on the ways, most likely a war time photo. Note the presence of the bearing indicator on the flying bridge, and what appears to be a Hotchkiss gun on deck. T. Woofenden Collection.
Second photo: Sea plane marked A-1686 next to SC 239. Tom Ruprecht tells me that this is a Curtiss HS-2L. Note that the chaser and others in the background have celebration flags flying. Also, the forward deck gun has been removed, and there's no bearing indicator on the flying bridge. This tells me this is probably a post-war photo, on a holiday. The men in tee shirts say summer, so I'm going to take a wild guess and say, July 4, 1919 at Hampton Roads, VA. Thanks to Donna Rutterbush, whose great uncle, Harry Daniel Hockman, served in the USN in WWI, for submitting the photo to The Subchaser Archives.