Answering the Old Question How Fast Were NOVEMBER Class Soviet SSNs Dont Miss the Link
By Bruce Rule - Jul 26, 2015
Russian open sources provide detailed design and performance characteristics that answer the long-standing question: “How fast were the NOVEMBER Class Soviet SSNs?”
The lead hull of the NOVEMBER Class, the LENINSKY KOMSOMOL (K-3), Project 627 – laid down on 24 Sep 1955 and underway on nuclear power on 4 July 1958 - had a maximum speed of 30 knots. The next 14 NOVEMBERs, Project 627A, with modified hull forms that significantly increased drag, had maximum speeds of 28 knots. One NOVEMBER, Project 645, was a test-bed for the Liquid Metal Cooled (LMC) nuclear reactor used by the ALFA Class SSN. All other NOVEMBERS had two Pressurized Water Reactors (PWRs). An improved (more hydrodynamically efficient) “cone-shaped” bow allowed the Project 645 NOVEMBER to achieve 30.2 knots.
Between 1958 and 1964, the Soviet Navy commissioned a total of 16 NOVEMBER Class SSNs: one Project 627 with two VM-A PWRs, 14 Project 627A hulls, also with two VM-A PWRs, and one Project 645 hull with two VT-1 LMC reactors.
Each VM-A PWR, rated at 70 MW, delivered 17,500 shaft horsepower (shp) to a 60-D (GTZA-601) “turbo-gear assembly” and also powered a GPM-21 dc turbo-generator rated at 1,875 hp for a total propulsion capability of 35,000 hp plus a total electrical output of 3,750 hp for both Project 627 and 627A hulls. These values equate to a conversion (efficiency) of 20.7 percent of the reactor output to useful power, most of the rest, nearly 80 percent, was lost in the primary-secondary steam loop heat exchangers.
Each VT-1 LMC (lead-bismuth eutectic) reactor rated at 73 MW, delivered an estimated 18,000 shp to a 60-D turbo-gear assembly and also powered am ATG-610 turbo-generator rated at 2145 hp. (One source states: the Project 645 “added ship-service turbo-generators, like those of Western nuclear submarines;” hence, the 645 was the only NOVEMBER Class unit whose primary electrical system was ac. All other NOVEMBERs used dc power. Collateral data supports this Project 645 assessment.
The hull-form modification to the 14 Project 627A NOVEMBERs that resulted in the loss of two knots involved the addition of a bow-area sonar dome – a “chin-mount” – that significantly increased the cross-sectional area of those submarines and the resulting drag. Project 627A hulls also were lengthened by eight feet to 360 feet.
It is assessed that an even more extreme bow-area modification of the NOVEMBER Class hull that attempted to intercept the USS ENTERPRISE (CVAN 65) in January 1969 reduced the speed during its 37.4 hour flank-speed run to 25-26 knots. Conjectures that this NOVEMBER operated at speeds as high as 31 knots were not supported by detailed collateral data.
All NOVEMBERs also had a turbo-electric propulsion mode that involved the use of shaft-mounted 450 hp PG-116 dc motors for an estimated maximum speed in that mode of about eight knots. Note: all NOVEMBERs except the Project 645 unit, had two DG-400, 460 hp diesel generators. The Project 645 hull did not have diesel-generators. This probably was a space issue.
See linked site to learn how the “USSR's first-ever nuclear (the LENINSKY KOMSOMOL) sub was destroyed by beer bottle cap.”
Also see the writers' archived article entitled “Unconventional Soviet Submarines” for discussions of the long-delayed USN decision to acknowledge the Soviets had operational nuclear submarines. It was System data that finally moved the Navy to make that admission about 1966, eight years after the NOVEMBER had become “more or less” operational.
Several Russian sources refer to use by NOVEMBERs of “low-vibration, silent propellers.” The Walker data inforned them otherwise.