I found this article on Google (unfortunately in Italian): http://www.regiamarina.it/somm.htm
The gist is that the Italian submarines at the start of WW2 were modern enough, but had a number of bad features that made their technical performance inferior to the German U-boats:
Most of these handicaps were corrected and modified during the first two years of the war. It's quite obvious that the italian U-boats performance would have been much better if they had been better prepared by June 1940 (which might be one of the minor PODs ITTL). The adoption of German tactics (wolves pack) can be happen pretty quickly.
The gist is that the Italian submarines at the start of WW2 were modern enough, but had a number of bad features that made their technical performance inferior to the German U-boats:
- significant time required for immersion/emersion
- superstructures too cumbersome, which affected capacity of maneuvering quickly
- lack of echo-goniometers
- lack of a centralised computing facility to aim and launch torpedoes
- torpedoes launched by compressed air, which often gave away the U-boat position
Most of these handicaps were corrected and modified during the first two years of the war. It's quite obvious that the italian U-boats performance would have been much better if they had been better prepared by June 1940 (which might be one of the minor PODs ITTL). The adoption of German tactics (wolves pack) can be happen pretty quickly.