Aircraft Carriers II (Closed to posting)

bd popeye said:

Correct.



Well that was back in 1961 when the Big E keel was commissioned and the keel was laid in 1957 I think. So the technology at that time probably had something to do with it. That's my guess..but..

I read this on line. I do not like the source.



We have a member named Ambivalent.. he has some knowledge of nuclear propulsion. Perhaps he can give an answer to your whole question..

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A smaller, lighter reactor space allowed for a better internal arrangement of machinery, improved compartmentation for resistance to battle damage and more magazine space.

bd popeye said:

Thanks for posting..but I'm going to move this post to the carrier thread.

I honestly did not think the USN could make this work in such short order. Look for EMAL catapults to be in service on CVN-78 class CVNs.

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Some very high ranking heads were going to roll if they failed. I'm sure some rectums unclenched in the Royal Navy too, lol.

You know, as interesting as the new Ford class will be, I'm actually even more excited to see the Royal Navy getting back in the business of tail-hooking again.

I'm really interested in why there are two reactors rather then just one. Are the reactors so unreliable, that you need two to remain operational between regular yard visits? Surely spending more on reliability would then save money?

^^Have you ever heard of an USN CVN not making a commitment because of reactor failure? I have not.

Neither have I. So why spend money on two reactors, when one would do?

Well delft everything in the US military is done with overkill in mind. A back up is always engineered in the design.

Ambivalent more than likely has the answer to that question. I'm guessing that it has to do with the power needed to move the ship and all it's auxiliaries i.ee machinerty, electrical, pumps electronics ...

delft said:

I'm really interested in why there are two reactors rather then just one. Are the reactors so unreliable, that you need two to remain operational between regular yard visits? Surely spending more on reliability would then save money?

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It has to do with optimizing the internal layout of the ship. Won't say more than that. Those reactors are very reliable but combat ships must be able to sustain damage. You also have packaging constraints that makes a big, single reactor, or eight smaller ones, less than ideal in terms of what other purposes the space taken could be used for.
All good engineering is about optimizing the compromises. The layout of the Nimitz class has proven in use to be very good. The ships last fifty years with only one complex mid life overhaul! Only the advent of AC electric propulsion, electromagnet catapults and A-gear, and soon the advent of directed energy weapons necessitating large amounts of electric current, has necessitated a serious deviation from the Nimitz orthodoxy. Think how long the Nimitz has been in production, how many were built and how little the design has changed over the decades.

But how likely is it, that a CVN after sustaining damage that knocks out one of its reactors, will be able to launch or receive aircraft without a visit to a repair yard lasting many months?

delft said:

But how likely is it, that a CVN after sustaining damage that knocks out one of its reactors, will be able to launch or receive aircraft without a visit to a repair yard lasting many months?

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Can't answer that unless I know what caused the damage. Torpedo, bombs, missiles. A torp could damage the ship underwater but leave the flight deck unscathed. USS Tripoli carried out her minesweeping mission during the Gulf War after hitting a mine ( I shake my head ). It put a seven by ten meter hold in the hull! The necessary compartments were sealed, the boiler re-lit ( the shock of the explosion blew the fires out! ) and the ship carried out the mission. Don't always assume a ship taking a hit immediately send that ship back to port for repairs. Study the history of the USS Enterprise during the Guadalcanal campaign as a lesson.
At least with two reactors the ship sails home under it's own power. Maybe not so fast as with two reactors but it's not immobilized. The cats use their own steam generators and operate at a higher steam pressure than the power plant does.

Ambivalent said:

Can't answer that unless I know what caused the damage. Torpedo, bombs, missiles. A torp could damage the ship underwater but leave the flight deck unscathed. USS Tripoli carried out her minesweeping mission during the Gulf War after hitting a mine ( I shake my head ). It put a seven by ten meter hold in the hull! The necessary compartments were sealed, the boiler re-lit ( the shock of the explosion blew the fires out! ) and the ship carried out the mission. Don't always assume a ship taking a hit immediately send that ship back to port for repairs. Study the history of the USS Enterprise during the Guadalcanal campaign as a lesson.
At least with two reactors the ship sails home under it's own power. Maybe not so fast as with two reactors but it's not immobilized. The cats use their own steam generators and operate at a higher steam pressure than the power plant does.

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Thank you. As an engineer I would want to estimate what it would cost to provide air power at sea, at what reliability, using aircraft carriers with two reactors or with one reactor and GT get home power. Would a carrier with half its power lost still be able to achieve the speed necessary to launch and recover aircraft?
What you said about a higher pressure steam system for the cats makes using EM cats seem even more attractive.