Seems strange to find something in Italy that has something that has been keeped. Normally everything that is in iron is missing from fortifications.
As I know, Isola San Pietro e Isola San Paolo are still military even if there is a kind of contract between Taranto to use them for tourist. There is some beach facilities too, so now I think there is a lot of people moving on that isles.
Italian Navy anyway is not using them and all the costruction are abbandoned.
Fortifications on that isle were realized by Napoleon in XVIII century. After Italian unification, Taranto became an important Navy base and San Paolo e San Pietro were part of the defence of the port.
According to what I found, on San Paolo there was 4 guns 149mm, 2 big guns in tower (400 mm), 4 naval guns 152mm and 4 guns 57mm.
In San Pietro there was 6 guns 280mm.
As I know, Navy used them in defence of Taranto during IIWW.
Here there is video about the degraded situation of the structures...:
http://www.youtube.com/watch?v=uoo8XYkG ... r_embedded