Pollack underway in the Atlantic off the coast of Maine and New Hampshire, March 1937. This cruise was likely post-acceptance trials meant to work out any remaining issues with the boat prior to her first deployment. Her 3"/50 caliber Mk 17 gun is mounted aft. The third photo may have been taken at the conclusion of a test firing of the gun, as there are a number of crew topside around the gun and on the forward deck.
All photos from NARA via historylink101.com.
Pollack moored to a pier, possibly at Portsmouth Navy Yard in Kittery, Maine. The time frame has to be between September 4, 1937 and November 29, 1937 when she left for the west coast.
The motor launch to the left is full of sailors in dress blues making the dating definitely after September 1 when the uniform change went from summer whites to blues. The pier where the launch is coming into has benches for people waiting for a launch to sit.