Official description: Six U.S. Navy submarines maneuvering in line abreast formation during exercises off Block Island, Rhode Island, in April 1947. The nearest submarine is USS Sarda (SS-488) while USS Torsk (SS-423) is next.
Note both Sarda and Torsk are in the late WWII “gunboat” configuration, i.e. fitted with 5-inch/25cal deck guns both fore and aft, augmented by two 40mm Bofors singles– quite a battery for a submarine. Such a layout was put to good use as, by 1944, most large Marus had been sent to the bottom already and targets worthy of a torpedo were increasingly rare– hence the prospect of easy dispatch via a 75-pound 5-inch shell. No fuss, no muss, no sending over a demo crew that could get hacked up with hatchets.
Of course, using such gunboat submarines in extended surface actions never proved ideal as they couldn’t carry enough rounds– which had to be passed up by hand chain-gang style from belowdecks– to make up for the fact that fire control from such a low-lying platform was a gamble at any range past point-blank, especially in any sort of sea state. See “Lattas Lancers” for a good lesson on that.
Plus, such an array of deck guns created drag and noise underwater, which was not ideal moving into the Cold War.
It was little wonder that, as part of the GUPPY program, the Navy soon stripped all the fixed guns from its subs.