Project 20836 Derzkiy-class modular Corvette

PapaDragon wrote:
Ah so it is CODAG plus electric

Definitely drastic improvement over what is now standard

It makes perfect sense​ then for this ship is so lightly equiped, it is a testbed for engine and hull

No need to install expensive weapons, sonars and radars on such an unproven vessel until you know for certain that core components actually work

COGAG (combined Gas and Gas), since they are 2 gas turbines.

CODAG means combined Diesel And Gas, like Admiral Gorshkov Frigate.

Furthermore it is not fully clear to me how does it work for the electric part... apparently it is only a partial electric propulsion with electric engines whose power is one order of magnitude smaller than the gas turbines.

Corvettes of project 20386 have a gas turbine power plant with partial electric propulsion. It has two M90FR engines produced by Saturn of 27500 HP each and two electric engines of 2200 HP each. Reducers and the gear of the 6RP unit are produced by Zvezda enterprise in St. Petersburg

Electric has enormous potential for the future... for a very long time the very idea that an electric motor in a car was the future was laughed at and derided by the majority, but the technology gets better and smaller and lighter and cheaper and pretty soon the fastest accelerating car will be electric if it isn't already...

Power and efficiency will improve and things like EMALS technology will drive things further too with better magnetics and power generation and storage and shifting electric power around a vessel like a star ship in Star Trek...

I should point out that a conventional motor needs gears and transmission shafts to redirect the mechanical rotation of the motor to the wheels that requires direct linkages.... on very big ships like aircraft carriers those shafts can be enormous and very very heavy and it dictates where the propulsion system has to be to turn the shafts to move the ship. You can run a diesel engine backwards though you usually have to stop it first, but some more complex transmission systems can reverse the shaft direction without having to reverse the motor driving it... with an electric motor you just change the polarity of the current.

Instead of big heavy propellers on enormous long heavy shafts you can have propeller pods that can rotate 360 degrees to make any size boat so manouverable tugboats become irrelevant... no gearing... no transmission, no drive shafts... the propeller pods contain the motors and the propulsion power generation system can be placed anywhere you like on the vessel... in fact you could have half a dozen different smaller power plants all over the place... a carrier could have the entire deck covered in solar panels if you wanted... with battery packs all over the place in empty spaces that nothing else fits in....

I assume that the red engines are diesels but they don't seem to be connected to the drive system. Are they auxiliary electricity generators?

Just looking at the photo at the top of this page the pinky red things are the diesel engines, which I assume just generate electric power, the orange are the gas turbines which are directly connected to the transmission which is blue, and the green are the electric motors which are also connected to the transmission, so the diesels would just be there to generate electricity to run the electric motors, while the gas turbines power the propellers through the transmission but I would assume could also turn the electric motors to generate electricity on board to run the electrics. The electric motors can turn the transmission to run the props but would get electrical power from the diesels to do so... I don't think there would be a run silent mode where only the electric motors run... you would either be diesel electric like a train or gas turbine like a helicopter... the diesels are fuel efficient but generally scalable power... the fact that there are three diesel engines shows they can have three cruise speed options... low speed standard speed and high speed with one, two or three diesels running at the same time, but generally the gas turbines generate the most direct power and are for high speed operations... often together with the diesels at the same time for max performance.

Awesome...

So would I be right in assuming that if they had the electric motors directly attached to the shafts they would not need gears or a transmission.... and in fact they could attach the propellers to the electric motors like the electric generators are directly attached to the diesels so the electric engines and propellers could be in pods hung below the keel that could be rotated 360 degrees so no need for rudders at all.

I remember seeing one of their icebreakers that was designed so it could reverse into really thick ice with its propeller pods running backwards so the enormous blades chopped up the ice to make it easier for the ship to operate in heavier ice packs...

Transmissions and gears are needed for internal combustion engines because the speed they run at (ie RPM) cannot equate to the speed of the wheels ( on a car or truck or bus or train) or the screws (on a plane or ships or subs) most of the time. Gears and transmission boxes and shafts allow the speed of the wheels and screws to be more effectively managed no matter what the RPM of the "engine" whether petrol engine, diesel engine, or gas turbine engine.

Well the thing is that modularity and serial production is one thing, but sometimes conditions make certain features more desirable than others.

What I mean is that right now the Russian Army has decided on four vehicle families... Armata heavy tracked, Kurganets medium tracked, Boomerang medium wheeled, and Typhoon light wheeled and they are going to develop those families and expand them to pretty much replace all their existing vehicle types within reason... ie you wont see Yars on any of them as it is just too big, but they can replace all the MTLB based vehicles and BMP and BMD based vehicles and BTR based vehicles in their forces.

However for the arctic they have shown they prefer DT-10 and other two part articulated vehicles for that region because with the powered articulated joint that transfers power to the rear catapillar tracks it means they can self recover if they fall through the ice into the sea water which single hulled vehicles can't do generally...

That means basing APCs or IFV or even artillery vehicles on the border with Georgia might be Armata or Kurganets or Boomerang or Typhoon... but in the far north it will be DT-30 based platform.

What I am saying is that the Steregoushchy might be the standard Corvette for most places in Russia, but the Mercury might be optimised... perhaps for shallow waters and rivers like the Caspian sea, or perhaps good in colder weather for the far north perhaps...

If they make an order for the Mercury boats for a specific location we might have an idea in that regard... maybe they want them in the Baltics or BlackSea/Med?

GarryB wrote:Well the thing is that modularity and serial production is one thing, but sometimes conditions make certain features more desirable than others.

What I mean is that right now the Russian Army has decided on four vehicle families... Armata heavy tracked, Kurganets medium tracked, Boomerang medium wheeled, and Typhoon light wheeled and they are going to develop those families and expand them to pretty much replace all their existing vehicle types within reason... ie you wont see Yars on any of them as it is just too big, but they can replace all the MTLB based vehicles and BMP and BMD based vehicles and BTR based vehicles in their forces.

However for the arctic they have shown they prefer DT-10 and other two part articulated vehicles for that region because with the powered articulated joint that transfers power to the rear catapillar tracks it means they can self recover if they fall through the ice into the sea water which single hulled vehicles can't do generally...

That means basing APCs or IFV or even artillery vehicles on the border with Georgia might be Armata or Kurganets or Boomerang or Typhoon... but in the far north it will be DT-30 based platform.

What I am saying is that the Steregoushchy might be the standard Corvette for most places in Russia, but the Mercury might be optimised... perhaps for shallow waters and rivers like the Caspian sea, or perhaps good in colder weather for the far north perhaps...

If they make an order for the Mercury boats for a specific location we might have an idea in that regard... maybe they want them in the Baltics or BlackSea/Med?

actually i believe having seen a diagramma that shows that the Mercury has better rough sea capability and can operate in worst conditions than the 20380/20385, making it more apt for occasional blue sea operations than its smaller older cousins