Also are there any drawing /images showing the Tuman and Amnok classes side by side, to make out clearly the differences between them, sizes, displacement, weapons fit etc.? To me it looks like on the www they are constantly mixing them up, and even say Tuman is a 3,000 ton Krivak hull.
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Amnok on the left, Tuman on the right.
They are actually the same size, although their original roles were not. Amnok was designed as a missile frigate, while Tuman was originally designed with a huge helicopter deck – presumably for the anti-submarine role.
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Apparently they realized that would be extremely inefficient so they converted it back into a missile frigate - essentially turning it into a "reinvented" Amnok, with a different forward superstructure.