I read news reports that this particular submarine was overhauled in a local shipyard, which is why they made such a big deal out of it when it happened. I think, if I got my facts straight, that the re-fitting operation taking place in Germany was actually a modernization of the sub's sensors and equipment, and not the aforementioned overhaul. I also heard a former head of the shipyard explaining how this sub's batteries were actually "recycled" and not replaced. There is a technical term for it but I don't know what it is, but basically if the outer shell of the batteries is deemed in good condition, then they just change the chemical components without actually removing and installing new batteries.
I just found
this video, which was actually published back when the actual overhaul was taking place. Below you'll find my attempt at translating what the narrator says:
After 2 years, Argentina regained a strategic capability, that of repairing submarines.An activity that was devastated during prior administrations.
Nowadays, in CINAR installations, the ARA San Juan’s state is being reverted. One of 3 active members of the Argentine navy submarine force, together with its twins, the ARA Santa Cruz and ARA Salta, The ARA San Juan sailed for the first time on June of 1983. Almost 2 years ago it arrived to our shops to begin what is known as “mid-life repairs”, a key maintenance effort which is the only time when the sub is cut in half, disassembled, fixed, and put together again through welding, the precision of which admits no errors.
The situation of the ship required this intervention to improve its navigation quality, deteriorated by hydrogen emissions from its batteries, which endangered its crew, and the submarine itself.
This event is a milestone for Argentina’s naval industry history. For this titanic task, CINAR joined forces with INTI
(don’t know what this is) and Argentine’s navy. Almost 2 years after being dry docked, the ARA San Juan is at a decisive stage, and all processes necessary for its final readiness are being accomplished. It marks the return of a giant of the seas which contributes to safeguard national sovereignty.
CINAR can confirm that Argentine Navy will be able to count again on one of its maritime insignias, and above all, ratify the national government’s decision of recovering Argentina’s naval industry.