Appendix G
Project 614 Foxtrot propulsion detail
A former Red Navy submarine officer, Captain Third Rank Igor Kolosov has kindly supplied most of the data for this appendix.
Keith Allen sent E-Mailed extracts from Kuzin and Nikolskiy's "The Soviet Navy 1945 - 1991". In particular
Project 611 (Zulu) had a three-shaft plant, the same as on the early Foxtrots" - "For the first time in Soviet boats, 400-volt power was used, for powering the middle main motor in motor mode. For battery-charging, a circuit was installed with a voltage of 320 or less. This design was used to save weight and volume in the middle main motor and its controls.
Other data matched Captain Kolosov's first hand information.
The Soviet Project 614 Foxtrot (2400 tons submerged as were the USN Guppy Fleet Submarines and the RN P Class & O Class), had three direct drive shafts with engine and tail clutches and three 2000 bhp geared diesels. The three double armature motors were directly mounted on each of the three shafts. As was the single 'Creep" motor aft on the centre shaft. The propellers were 1.72 m for the two outer shafts and 1.68 m for the centre shaft.
The Foxtrot had 448 large cells (300 x 700 x 1200 mm) and maximum speed of 14 knots for over 2 hours, giving a better endurance to Guppy II submarines of similar displacement. The 1952 Project 611 Zulu is assumed to have similar propulsion as the later Foxtrot and apparently used again by the later and bigger Project 614B TANGO.
(Fig 9) is an entirely speculative sketch that rationalises the apparently contradictory reports that 200 or 400 volts were used with the three separate motor controllers with no obvious series/parallel battery grouping switches shown in the clear photographs of preserved vessels. (Fig 9) makes the assumption that the larger centre motor (2700 shp) was permanently supplied with 400 volt while the two smaller outer motors (1350 shp) were permanently supplied with 200 volts and also did all the battery charging - The reality might quite different - all comments welcome
Captain Kolosov advised his submarine could make 6 knots at 2 x 200 shp on the two outer main motor shafts. (Fig 9) and that 6-8 knots was the usual speed range submerged. with a maximum of 14 knots with a range of 30 miles (2.07 hours. At slow speeds this would translate into a very useful submerged endurance! Using the calculated results in Appendix B, the Guppy II could only manage 14.5 knots for one hour!
In the opinion of Jeff Tall, Royal Navy SSN and SSBN Commander,
The Foxtrot was a splendid class of 62 diesel-electric submarines - They highly successful and reliable and were deployed worldwide, bearing the brunt of Soviet foreign deployments. They were most numerous in the Mediterranean in the 1960s and 1970's Appendix I
As far as can be ascertained, the smaller submarines of the era, Project 611 Whiskey and later improvement, Project 633 Romeo, both with twin shafts, had direct drive propulsion very similar to the two outer shafts of the Zulu/Foxtrot, but with a creep motor on each shaft. The Romeo has been built in China for the Chinese navy in some numbers.
Pat Householder after reviewing the article, drew attention to the fact that the single "creep" motor in the Foxtrot class used a motor controller cubicle very similar to the three main motor units. In the Chinese twin shaft Romeo class, a smaller, quite different controller appears to have been used for the two smaller "Creep" motors, one for each shaft. A recent photograph is available of an extant boat in China, where, what seems likely to be a "creep" controller, can be seen.
It is reasonable to assume the Soviet Whiskey and Romeo used a similar arrangement in submarines that were substantially smaller than the Foxtrot.
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