052C/052D Class Destroyers

Iron Man said:

Not necessarily. I'm not a naval engineer or anything but as far as I understand it, with mechanical transmission you have two sources of noise: the transmission, and the engine, both of which can be isolated from the hull by rafts even if they are connected to each other physically. In IEP, you also have two sources of noise: the electric motor, and the engine, both of which also can be isolated from the hull by rafts. I think which one is quieter in the end is whether the electric motor is quieter or the transmission is quieter rather than the fact that IEP has two separated sources of noise. I would amateur guess that an electric motor would be quieter compared to a mass of gears grinding each other along.

Click to expand...

charles18 said:

In a conventional ship you have an engine -> transmission-> drive shaft -> propeller
Even if the engine and transmission is placed on rubber dampeners to reduce noise the engine vibrations will still be transmitted to the ship's hull through the drive shaft. There's no way around it.
In an IEP system there is no drive shaft.
(maybe in the shipping world the proper term is propeller shaft not drive shaft but you get the idea)

Click to expand...

Iron Man said:

In an IEP system there is absolutely still a drive shaft. You must be thinking of rim drives ("rim-driven thrusters"), that's the only way I can see how your post makes sense. I have no doubt multiple countries are working on rim drive technology for main drive propulsion but AFAIK currently this technology is only in use for small propellor systems like the ones used for pier maneuvering or used as main drives on boats, rather than as main propulsion systems for large civilian or naval vessels. Probably this is coming down the road but we are not there yet.

By way of an example of IEP, here is Daring's propulsion system (notice the drive shafts):
View attachment 146665

Click to expand...

iBBz said:

I'm not an expert of marine engine configurations and don't know much about their firing orders either, but I'm thinking the benefit here could be that motors are smoother because they operate at higher frequencies than ICE engines, so that produces less vibrations. Am I correct in making this assumption?

Click to expand...