Those modern "old technology" subs are a nightmare for ASW units because they emit a lot less noise than a nuclear sub does.
While doing ASW drills together with US carrier groups, the german diesel electric subs regularly managed to sneak up on the carriers and hunter subs unnoticed.

Thanx for that info rarcand. I have another photo of it from a slightly different angle but as they were taken through the window of a coach I don't think they are eligible for inclusion into the site unless I can try some Photoshop wizardry. I thought all Russian subs were nuclear now. Didn't realise some still operated on the old technology.

It looks like a Kilo class diesel electric sub. Since Russia has 26 of these (22 original design and 4 of an improved one), the name of this ship will not be easy to find.