Majority of the following text and photo i.d. courtesy of Dave Johnston (USNR).
Text accompanying this photo reads "Enlisted men repair and check instruments aboard a submarine just returned to Pearl Harbor, Hawaii. May 1945."
Note: Many of the captions of Bristol's photography are lacking in details and some have the wrong dates, places and locations.
The "23" boat in question in this photo is definitely NOT the S-23 (SS-128). It is beyond a doubt a Salmon or Gato/Balao class fleet boat, and I would lean toward a Balao. The date of the photo is probably early to mid 1944.
The boat in question has the characteristicly fat, twin periscope shears and long, wide flat "cigarette" deck of a Balao. Directly above the head of the sailor who is working at the base of the aft scope is a radar mast. The sailor behind him is standing at and looking through the aft Target Bearing Transmitter (TBT). Barely visible on the far left of the photo is what I believe to be part of a 20 mm gun mount.
None of these features were ever present on any of the S-boats, even the later 40 series that were heavily modified (i.e. S-45 (SS-156) ) towards the end of the war. The whole conning tower fairwater on the boat in question is simply too large for a S-boat.
As for the "23" on the fairwater, I have seen wartime photos of fleet boats displaying mysterious one and two digit numbers that do not correspond to their hull number (see the Guardfish (SS-217) and Peto (SS-265) pages for examples). Despite a lot of research, I have not turned up an official explanation for these strange numbers. One source said that they were squadron or flotilla identifiers, but I can't back this up officially. It is possible that they were temporary numbers assigned while the boats were in home waters, maybe to cut down on friendly fire incidents. Strangely enough, these numbers also seemed to have been used briefly during WWI, as I have seen them on D, E, F, G, and H-class boats.
It is also entirely possible that these numbers are part of an official disinformation program designed to obscure the identities of the boats while allowing a wide distribution of photos to an information hungry wartime public. That would also account for the information inaccuracies attributed to otherwise highly thought of photographers.
Riveted construction on the conning tower fairwaters of the fleet boats was far more common than I previously thought. It seems that the fairwater plating was riveted to the supporting structure underneath during construction on virtually all of the fleet boats, no matter who built it. This was possible due to the fact that the fairwater was non-watertight and merely provided for a smooth flow of water around the conning tower and lower periscope shears.
Riveting was a long practiced and well known construction method, while welding was still relatively new and there was a fairly low number of skilled and experienced welders, and they had to be parceled out carefully depending on priority. All of the pressure resisting elements such as the conning tower and the main pressure hull were welded. The last fleet boat to have a riveted pressure hull was the Pompano (SS-181) in 1937. These original riveted fairwaters were retained until the end of the war, unless the boat had major rework of the fairwater performed (like most of the Gato's), or if the boat suffered battle damage. The rework jobs seemed to have been mostly welded.
I would lay money on it being a Manitowoc built Balao class and I will stick with the early to mid 1944 date.