They were not crewed by Argentines all the way nor was it a mission of that Government
Are you talking about 30 day range of stores onboard? That is easy to replenish along the way
A she is designed o go 12KNM on a single tank of fuel, and only 8 Knots on top
Look up WW2 subs on the surface, I am sure her specs are better than that, underwater I can see that
Speed:
15 knots (28 km/h) surfaced
25 knots (46 km/h) submerged