The "Secretary" class of USCG high endurance cutters (named after Secretaries of the Treasury in recongition of the USCG's origin as the Revenue Marine under the Treasury Department) has a long and proud history. It originated as a Navy "Peace Cruiser" design. This was a small vessel of relatively limited military cpability intended to "show the flag" and perform mainly diplomatic and humanitarian missions in peacetime. The name-ship, USS Erie, was commissioned in 1936. She had a modest top speed of 20 knots with a hull form optimized for that, resulting in the characteristic spoon shaped rounded stern, a feature that was no longer used on Navy cruisers at this date. This same hull form gave her exceptional efficiency (8000 miles range at 12 knots) and favorable motions in high seas for a small ship of about 2500 tons. The Navy version had a substantial defensive armmament, including 6" guns and an armor belt at the waterline. However, somewhat inconsistently, the machinery installation with both turbines in the same room did not fulfill then-current Navy standards for survivability.

The Coast Guard version used essentially the same hull lines but differed internally and had, to begin with, 5" 51-cal. guns, normally a battleship secondary gun in the World War I era and obsolete by the time the first "Secretary" was commissioned, the same year as Erie. As can be seen in the photo, Duane has a 40-mm. Bofors "quad" in "A" position and a twin of the same type in "B". Postwar, she had a 5" 38-cal. dual purpose gun (a WW II-era destroyer weapon) in "A" position.

The Wikipedia article on Duane [http://en.wikipedia.org/wiki/USS_Duane] indicates she was rebuilt as an amphibious force flagship in 1944. This could have something to do with her presence in Italy at this stage of the war. However, she was not taken over by the Navy and continued in Coast Guard service into the 1980's, as many of the Secretaries did. The surviving sister, Taney, is in Baltimore today where she's serving as a museum. This class of ships were particularly well liked in USCG service and therefore led exceptionally long and active lives. Seven were built, and except for Hamilton, sunk in action in Jan. 1942, all were still in service in 1980 after more than 40 years.