The young can get away with so much, can't they?
The description for this photo, originally published in the Rochester Herald on September 22nd, 1918, reads:
"Russell Dean of the U. S. Navy is the winner of the 100-yard swim in the city swim meet. He wears a garter-stitch knit sleeveless top in this waist-length portrait."
Credits: From the Albert R. Stone Negative Collection, Rochester Museum & Science Center Rochester, N.Y.
You gotta love libraries!
If you click on the image, you can see the knitting better. Wonder if he knit it himself?