The Russians Are Resurrecting the LADA Class Diesel Time to Review What We Know From Open Sources
By Bruce Rule - May 18, 2015
The seriously flawed lead ship of the Project 677 LADA Class SS, the ST PETERSBURG, was never accepted by the Russian Navy. The second unit of the class, the KRONSHTADT has been extensively modified to correct power and sensor deficiencies identified during testing of the ST PETERSBURG to the extent that, as discussed by a senior Russian construction engineer, it “isn't being built but rather created,“ i.e., basically the KROSHTADT is the lead ship of a new class, Project 677M.
Transfer of the KRONSHTADT to the Russian Navy is scheduled for 2017.
Construction of the lead LADA unit, the 2700t submerged displacement ST PETERSBURG, started in December 1997; it was launched in October 2004 and, although commissioned in May 2010, the Russian Navy did not, after eight years of trials, accept the unit because the submarine's propulsion and sonar systems were “inadequate.” (The main propulsion diesel(s) was reported to have been a “crude engine which proved unable to develop more than half of the given project power.”)
Russian Navy support of the program was terminated. Production of the AMUR 1650 Class, the export version of the LADA, also was suspended.
The ST PETERSBURG design used two constant speed (1,000 rpm) D49 diesel engines (V8 design) operated as diesel-generators: a diesel-electric propulsion system. A candidate engine was the V8 configured ED-2, a D49 (ChN26/26) engine (bore of 260mm and a stroke of 260mm). The ED-2 operates at 1,000 rpm to drive a six-pole generator to produce 50 Hz power which can be converted to dc power for propulsion reported to have been provided by a 2700 hp motor which compares to 5575 hp PG-141 motor for 3950t submerged displacement Project 636 KILO Class units.
The Power Factor for the Kolomna D49 ED2 diesel-generator, rated at 1750 hp at 1000 rpm, is 0.80 which equates to an electrical output of 1045 kW.
The “footprint' – required deck space – of the ED-2 is about 50 square feet which compares to a footprint of about 90 square feet for a 1720 hp 1DL42 (ChN 30/38) engine plus generator system which is similar to the diesel-generator used in Project 877 KILO Class submarines. Thus, use of a 1,000 rpm V8 diesel-(ac) generator in LADA/AMUR hulls instead of an in-line, 6-cylinder 700 rpm diesel-(dc) generator reduced the required deck area by nearly half and increased available electrical power by about five percent. The displacement of the V8 D49 engine with bore and stroke of 260mm is 31.5 percent less than the displacement of an in-line, 6-cylinder D42 engine with a bore of 300mm and a stroke of 380mm.
All well and good if the ED-2 produced its rated power which appears not to have been the case.
MODIFICATIONS MADE TO THE KRONSHTADT USING A “CORRECTED TECHNICAL DESIGN”
A new bow module to accommodate unidentified changes to the sonar system.
A new stern module joined at the aft end of the fourth compartment with “upgrades to the end of the stern section” that include adjustments in the design of the shaft line as per directions from the Rubin Central Design Bureau of Naval Technology.
The layout of the fourth and fifth compartments where the diesel generators and electric propulsion motor are located was changed.
All open sources are consistent with the conclusion that the ST PETERSBURG, the lead hull of the LADA class, could not develop the designed submerged speed of 21 knots. This suggests the 2700 hp main propulsion motor has been replaced with a more powerful system which required modification of the fifth compartment and the propeller shaft line.
It also is possible the reportedly underpowered ED-2 diesel generators have been replaced. If that replacement involved the KILO Class 1DL42 diesel-generators or a more powerful variant of that engine, a lengthening of the hull may have been required.