Subchaser SC 208.
Henry Miller writes on the reverse: "Now don't tell me that a sub chaser will not dive, for this picture proves it. We were running with a long, rolling sea at twelve knots. Just the right speed to dive in."
As this photo so pointedly shows, the chasers were often very wet boats.
Photograph of SC 208, courtesy of Bobbie Miller, daughter-in-law of SC 208 crewman Henry Miller.