Related to Ballaban’s article about the new Australian Navy Attack-class submarines, I was looking at other SSKs (diesel electric subs), and noted that the Russian navy had been working on a follow-on to their wildly successful Kilo-class subs, but due to “major deficiencies” with the lead boat, construction had been suspended. The Sankt Peterburg was found to be under-powered, with an inefficient sonar and was poorly built overall. 

The other two Lada-class subs being built at the time were left unfinished.