Chinese Marine Propulsion

[BoraTas]

I stumbled upon a rather interesting paper by a Dutch guy which gives recommendations for the Dutch ASWF frigate

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It mainly talks about CODLAD, which is what was used for the ASWF.

It seems to say that even with CODLAD arrangement of 4 x MAN 16V28/33D (7.28MW each) + 2 x MV 560 (generating 2.6MW each for electric drive) for a total of 34.32 MW, max speed for a 6000 ton ship is only 28.4 knots.

Even if you increase power of the 4 main propulsion engines to MAN 20V28/33D with 9.1MW each for a total of 36.4MW, max speed is only 28.7 knots.

I think this tracks with what we've seen in the past, like Iver Huitfeldt class uses four 8.2MW diesel engines and is also limited to 28 knots. Generally seems like 28 knots is a limit for 4 x diesels, even with electric motors assisting. It also means 054B with 4 x CS16V27 (7.28MW each) is probably close to the size limit if they don't want speed to drop below 28 knots.


I think this is a bit of a headache for a proper 054B successor IF we assume the requirements for it are:
1. quiet enough for ASW
2. able to sustain over 30 knots to keep up with carriers
3. cheap enough to mass produce

To fulfil 1 you ideally want electric motors, so diesel electric + something
To fulfil 2, this paper says that CODLOD / CODLAD are eliminated because they just aren't fast enough. Unless you go with something ridiculous like 6 main diesels. So you're basically forced to go with a gas turbine. So a proper 054B replacement will probably need CGT-30 + diesel electric, which is a rather big change and rather expensive, so it contradicts 3.

CODELAG is pretty much the standard in new gen European frigates right now. It offers good sprint performance thanks to the gas turbine and the combiner gear which allows the diesels to still contribute. In lower speeds it allows great efficiency, plenty of electricity, and silence by running on diesels that use e-transmission (generator + e-motor). It can run on a single diesel in even lower speeds too. It can be considered a step below IEP for not using a e-transmission on the gas turbine. Going full IEP is expensive and uses a lot of volume because you need to add a huge generator and e-motor. All these make CODELAG a good compromise for frigates. IEP would be for DDGs, LHDs and CVs.

 

[sndef888]

CODELAG is pretty much the standard in new gen European frigates right now. It offers good sprint performance thanks to the gas turbine and the combiner gear which allows the diesels to still contribute. In lower speeds it allows great efficiency, plenty of electricity, and silence by running on diesels that use e-transmission (generator + e-motor). It can run on a single diesel in even lower speeds too. It can be considered a step below IEP for not using a e-transmission on the gas turbine. Going full IEP is expensive and uses a lot of volume because you need to add a huge generator and e-motor. All these make CODELAG a good compromise for frigates. IEP would be for DDGs, LHDs and CVs.

Yeah CODELAG is great, but I'm just concerned about the cost, switching from all diesels to diesel genset + GT + combining gear doesn't make sense for a cheap frigate.
At that point you might as well add in another GT and make a 9000 ton 052D successor

So just wondering, for a potential 054B successor, whether it'll be worth it to sacrifice 30+ knots speed, and just go with a CODELAD

 

[ACuriousPLAFan]

Excerpts from an academic paper, exploring and discussing the usage of light diesel oil (LDO) versus heavy fuel oil for steam-powered ships. Posted by SOYO on Weibo.

Combined with what 塔子 mentioned some months ago, it seems to indicate that the PLAN could be looking towards switching the oil type for their steam-powered warships, which would be hugely beneficial for their fuel logistics.

 

[tphuang]

https://twitter.com/i/web/status/2069489060276478240

Weichai JV producing eShipping battery packs. Pure battery electric boats that can operate peacefully and easily maintainable and rechargeable.

 

[AndrewS]

I stumbled upon a rather interesting paper by a Dutch guy which gives recommendations for the Dutch ASWF frigate

Please, Log in or Register to view URLs content!

It mainly talks about CODLAD, which is what was used for the ASWF.

It seems to say that even with CODLAD arrangement of 4 x MAN 16V28/33D (7.28MW each) + 2 x MV 560 (generating 2.6MW each for electric drive) for a total of 34.32 MW, max speed for a 6000 ton ship is only 28.4 knots.

Even if you increase power of the 4 main propulsion engines to MAN 20V28/33D with 9.1MW each for a total of 36.4MW, max speed is only 28.7 knots.

I think this tracks with what we've seen in the past, like Iver Huitfeldt class uses four 8.2MW diesel engines and is also limited to 28 knots. Generally seems like 28 knots is a limit for 4 x diesels, even with electric motors assisting. It also means 054B with 4 x CS16V27 (7.28MW each) is probably close to the size limit if they don't want speed to drop below 28 knots.


I think this is a bit of a headache for a proper 054B successor IF we assume the requirements for it are:
1. quiet enough for ASW
2. able to sustain over 30 knots to keep up with carriers
3. cheap enough to mass produce

To fulfil 1 you ideally want electric motors, so diesel electric + something
To fulfil 2, this paper says that CODLOD / CODLAD are eliminated because they just aren't fast enough. Unless you go with something ridiculous like 6 main diesels. So you're basically forced to go with a gas turbine. So a proper 054B replacement will probably need CGT-30 + diesel electric, which is a rather big change and rather expensive, so it contradicts 3.

Remember that the requirement for a Frigate to go over 30 knots only comes from escorting aircraft carriers, and even then, we're only looking at a single ASW Frigate per carrier group.

There's no point in developing such a Frigate design for only a few ships, at this time.

Better to just use a Type-052D destroyer instead, or develop a small specialised 1000 tonne ASW ship/boat which does have the speed to keep up with a carrier group.

Even if such a ship/boat is not part of a carrier group, the high speed will be useful in outrunning torpedoes because this is the ship you send for high risk ASW because it is the most expendable.