Russia inherited a vast, if not bloated, catalog of Soviet submarines built in the decades following the Cuban Missile Crisis. Many of these fell into disrepair over the 1990’s due to insufficient maintenance. Others were simply not needed in the context of Russia’s new geostrategic goals, at least not the massive quantities typical to Soviet submarine production.

Over the early 2000s, Russia’s submarine modernization program was primarily concerned with the problem of what to with these Soviet vessels; which should be refitted, and which should be decommissioned? How “deep” can a refit be-- that is, how many core components need to be swapped out-- before it stops being cost-efficient?

But in the present day, these questions have been asked and answered. With the fate of most Soviet-era submarines now clear in one way or another, the Kremlin is eyeing the next generation of Russian submarines. By far the most anticipated of these is the Borei and Yasen classes; the former is a ballistic-missile submarine meant to replace the aging Delta and Typhoon lines in Russia’s nuclear triad, while the latter is to be Russia’s flagship cruise-missile attack submarine. Yasen’s current incarnation is Yasen-M, an iterative upgrade meant to account for the sixteen-year window between the first commissioned Yasen vessel and the upcoming Kazan submarine.

Whereas Borei development and production has been moving along at a slow but steady pace, the Yasen-M project continues to face delays. According to a statement made by a Russian defense insider to the TASS state news agency, Kazan will not be delivered to the Russian in 2019: "Following the results of dockside trials, and also the winter stage of shipbuilders’ trials [which ended in January], it has been established that some of the ship’s auxiliary sub-assemblies and mechanisms do not meet the requirements of the specifications set by the Defense Ministry, including reliability characteristics, and require finalizing in the Sevmash dock."

The scale of development work on these “auxiliary” systems is so great that Yasen stands to be delayed by an entire two years: "It is absolutely unrealistic to accomplish all this by the end of the year. It is not ruled out that the entire year 2020 will be required and the Sevmash Shipyard will be able to deliver the sub to the Fleet only in 2021."

Seemingly corroborating TASS’ anonymous source, United Shipbuilding Corporation (UAC) chief Alexey Rakhmanov complained to RIA News--another state media outlet-- that “testing submarines is not easy. we are talking about how the control systems, which were used for the first time on this submarine, work. Besides, I won't lie, a number of design flaws were discovered."

It remains unclear precisely what these “design flaws” consist of. Not counting the sixteen-year hiatus between Yasen and Yasen-M, Kazan was already once delayed after being scheduled for a 2017 delivery. The reasons for that delay remain equally as murky as this one, though Russian industry sources suggested that logistical-industrial and financial issues were to blame. By comparison, Kazan’s current problems appear to be of a decidedly more technical nature.

Nonetheless, monetary concerns will continue to figure prominently into Yasen-M’s fate. Given the strain of producing two new submarine classes at once, pushing back Kazan’s launch could offer the Russian military-industrial complex much-needed breathing room to push out the Knyaz Oleg and Generalissimus Suvorov Borei-line submarines over the coming year before turning their resources back to the Yasen project.

Mark Episkopos is a frequent contributor to The National Interest and serves as research assistant at the Center for the National Interest. Mark is also a PhD student in History at American University.