While searching for information on Iranian submarines, I discovered this fascinating blog which provides open source intelligence on the world’s navies. It’s good reading to a former Navy spook such as myself!
Since before the Second World War, Italy has been a prolific designer and producer of small submarines. The CA and CB-class midget submarines and their operational histories are already well-known, but those produced post-WWII are much less known, poorly documented and the subjects of confusion and misinformation. Fincantieri, Maritalia and Cos.Mo.S. are all known to have produced viable small submarine designs, however only Cos.Mo.S. is known to have definitely produced actual small submarines, albeit all for export.
via Covert Naval Blog.