A lot of misconceptions and plain mistakes circulate around both Pr. 677 "Lada" class and its latest export version "Amur-1650",i think it will be useful to delete them one time for all.
Russian MoD and Navy's Command WILL NOT accept Saint Petersburg , the lead ship of the class on two main basis : underperforming propulsion at high regimes and inconstant/somewhat insufficient energy supply to some key components (among which main sonar).
The Saint Petersburg has been already used as a tests specimen to validate the functions and sort-out all the problems related to any other system of the Lada class (in particular Lira main sonar showing performance's parameters by a good margin superior to those of any other passive and active sonar mounted on non-nuclear submarine worldwide) but NOT those related to energy storage and propulsion.
The reason is very simple, "Saint Petersburg" was designed and constructed MUCH BEFORE the achievement and validation of two recent technological breakthrough in those segments :
A new generation of Lithium-ion battery with energy capacity to volume/weight ratio several times greater than the best lead-acid mounted on foreign SSKs
An almost revolutionary AIP ,based on hydrogen reforming from common diesel fuel aboard, much more silent, compact and safe than the competitor hydrogen-store based systems and capable to produce over 400 Kw against the 180 maximum of the best foreign competitor !!!
Those two new systems will be mounted ,respectively, on the second ship and third ships (the construction of which was purposely frozen waiting for the completion and validation tests of those two systems).
Kronshtadt will mount the Lithium-ion batteries while Sevastopol will mount both the Lithium-ion batteries and the AIP
Amur-1650 will integrate the export version of BOTH of those two systems ,therefore if today it already vastly surpass all its competitors in the fire power, main sonar and acoustic/magnetic signature suppression department ,within 4-5 years ,with theirs integration, it will occupy a true league of its-own in the SSK market's sector.
I rather doubt the western alternative subs are perfect either and will have problems too.
Absolutely true GarryB Not only they will have.... them had already had problems.
Terrible experience of the Type-214 in Hellenic and Korean Navy service anyone ?