Ohio-Class Subs to Shift to Electric Drive

[Feuer Frei!]

The U.S. Navy’s future Ohio-class submarines will feature an electric propulsion system, making them even quieter and stealthier than today’s versions.

SOURCE

[Wolferz]

All of our subs are electric drive.

[Platapus]

Being a lubber of land, I am confused as to exactly what this means.

Does this mean there there will no longer be a steam turbine used?

[Jimbuna]

So the technology used in Red October has finally been assimilated

[Buddahaid]

I've already got one.

[Oberon]

It's not quite the same as the current engines, nor is it magneto hydrodynamic (caterpillar). It's a bit like a bigger version of the creep motors on boomers. Rather than two motors mechanically driving a screw shaft, it'll be an engine connected directly to the shaft, so there's no need for clutches or gearboxes for transmission which reduces the sound signature.
Like the article says, the Zumwalt will have a similar system, here's the wiki link for it:
http://en.wikipedia.org/wiki/Integra...ric_propulsion

The next big thing though is magnet related, the Permanent Magnet Motor, which should probably be very quiet indeed, whilst still maintaining a good level of horsepower.

[Jimbuna]

A bit like our Type 23's

[Oberon]

Originally Posted by Jimbuna

A bit like our Type 45's

Fixed that for you.

[ETR3(SS)]

Originally Posted by Wolferz

All of our subs are electric drive.

Not sure what you're getting at, but no they're not.

As for this new system I believe it was first tested on Tullibee with less than impressive results. My one concern with this is the electrical power required for propulsion. You need an electric motor that can generate 60k shp to keep up the current standard. And I fail to see how adding a large drain on the ships electrical grid will provide more power for other systems. Adding a more powerful reactor will do that.

But hey I'll wait and see how it turns out.

[Kazuaki Shimazaki II]

Originally Posted by ETR3(SS)

Not sure what you're getting at, but no they're not.

Based on his handle, I think Wolferz is German.

As for this new system I believe it was first tested on Tullibee with less than impressive results.

Well, it was too slow, but then technology did make some strides. Besides, a boomer arguably needs silence more than it needs speed.

My one concern with this is the electrical power required for propulsion. You need an electric motor that can generate 60k shp to keep up the current standard. And I fail to see how adding a large drain on the ships electrical grid will provide more power for other systems. Adding a more powerful reactor will do that.

Going to turbo-electric, there will be one big generator instead of a steam turbine and a few "service" generators with limited capacity, so the reactor's whole output can be diverted to electrical systems instead of a fraction.

[Stealhead]

Originally Posted by Kazuaki Shimazaki II

Based on his handle, I think Wolferz is German.

No he is an American from Ohio I think not sure what state but he is an American.Pretty sure he was in the US Army at one point.I recall him mentioning it at some point.

[Platapus]

So that long trailing wire coming from the stern is the extension cord?

[Wolferz]

Originally Posted by Platapus

So that long trailing wire coming from the stern is the extension cord?

It does double duty as an antenna and it can be used to catch tuna by adding a hook and some bait.

No I'm not German. I'm a mutt who currently resides in Pennsyltucky.

That's all I'm gonna say because you can't open the book of my life and just jump in the middle.

[ETR3(SS)]

Originally Posted by Kazuaki Shimazaki II

Going to turbo-electric, there will be one big generator instead of a steam turbine and a few "service" generators with limited capacity, so the reactor's whole output can be diverted to electrical systems instead of a fraction.

I understand what you're saying that by getting rid of the steam main engines you could divert that steam to generate electrical power. You still need to generate more power to supply the demand of the propulsion train now. So you got rid of the main engines to replace them with more turbine generators to supply the demand. But most of the power generated by a reactor goes to powering the reactor systems anyway. I'm lost on how they are going to accomplish this within the limited space of a submarine hull.

[Kazuaki Shimazaki II]

The difference is one of losing a "forced border". Take, oh, a Victor-class. The reactor is credited with 72MW thermal. The thermal efficiency of a PWR is only about 30% or so, so with the 72MW thermal, it can feed the shaft with about 31000 horsepower (~23MW) and it also has two little OK-2 turbogenerators with a total capacity of 4MW - total of ~27MW of work.

Thus, the Victor's electric systems (to include the coolant pumps, any other pumps, the lighting, the heating, the washing machine, the active sonar ... etc) cannot use more than 4MW.

If you change it with a turboelectric system, then you have about 27MW of electrical supply. Which you can freely apply to propulsion OR any electronic systems (such as a uber-high powered low frequency active sonar) you have. The latter is an important consideration with the increasing proliferation of advanced electronics on ships.