Thanks guys.
This is DACE (SS-247) in May of 1945, at the start of the boat's seventh war patrol. She is camouflaged in Measure 32/3SS-B - the standard grey scheme with black pressure hull found to be very effective at defeating surface observation.
DACE shows a very typical late-war GATO class configuration, with SD and SJ-1 search radars on masts aft of the periscope shears. The two 40mm Bofors Mark 3 single mounts fitted to the fairwater proved their worth during the waning months of the war, as most of the enemy ships engaged by the submarines were mainly junks and sampans (too small to be hit with torpedoes). A 5"/25 deck gun is fitted aft. The most interesting feature of DACE during this period is the DBU radar countermeasures system fitted on either side of the fairwater (just visible as a series of receiver antennas immediately forward of the side lights). This was a slight improvement over the APR-1 system usually installed, and saw service on several boats.
DACE survived the war to serve in the postwar US Navy, before being transferred to Italy. Renamed LEONARDO DA VINCI (S-510), ex-DACE served in the Marina Militare Italiana until 1972, when the boat was returned to the US. It was sold for scrap in 1975.