Soviet Navy — Kvaker USO Program (Программа «Кваkeр»)

Throughout the 1970s, Soviet Navy submarines and surface vessels repeatedly detected anomalous underwater objects that emitted distinctive repetitive croaking sounds, earning them the unofficial designation 'kvakers' from Soviet naval personnel. Declassified Soviet Navy files compiled under the authority of Admiral Nikolay Smirnov documented contacts with objects tracked at underwater speeds that exceeded the maximum performance of any known submarine by a substantial margin, often pursuing Soviet submarines before departing.

The kvaker phenomenon was serious enough to warrant a formal Soviet Navy investigation program — the quasi-official 'Kquaker' program — that compiled sonar data, contact reports, and analysis from submarine crews across the Northern Fleet and Pacific Fleet over several years. The program's existence confirms that Soviet naval command treated the contacts as genuine operational concerns rather than sonar artifacts or natural phenomena. Admiral Smirnov's personal involvement in compiling the documentation gave the program a level of institutional seriousness consistent with a genuine threat assessment.

Tracked speeds for the underwater objects, as recorded in the Soviet naval files, ranged from estimates of 70 to over 100 knots submerged — compared to the maximum submerged speed of approximately 30–35 knots for the fastest nuclear submarines of the era. Several contacts showed the ability to transition between underwater and aerial modes of operation, behaving as transmedium vehicles capable of functioning in both the ocean and atmosphere. The transition capability, if accurately recorded, would describe a category of craft with no human-engineered equivalent.

The croaking sounds emitted by the objects were distinctive enough for sonar operators to recognize them as a consistent signature — not random biological noise or mechanical artifact but a repeating, characteristic acoustic pattern. This acoustic signature allowed Soviet crews to identify kvaker contacts consistently across different vessels and operational areas, suggesting a population of objects with consistent acoustic properties rather than isolated anomalous readings.

Soviet naval USO data was partially disclosed to Russian civilian researchers after the Soviet Union's dissolution, and Admiral Smirnov's documentation became a key resource in Russian UAP/USO research. The kvaker files represent the most systematically compiled body of military sonar USO data from any nation and parallel the U.S. Navy's 'Range Fouler' files in the Santa Catalina Channel as institutional documentation of anomalous underwater contacts.