00X/004 future nuclear CATOBAR carrier thread
- Thread starter AETHER
- Start date
That entirely depends on how much more capable the CVN will be than 003.
If they want to add another catapult, lengthen the overall hull for another 15-20m, move and redesign the island to be smaller, add another elevator, widen the flight deck in parts... All while replacing the steam propulsion with nuclear (and the requisite changes in internal piping, fuel and stores storage etc)... That is basically a whole new design.
Not quite fully clean sheet, but pretty close. 3-4 years is pretty reasonable given that.
If they were designing a clean sheet carrier without 003 to work from, they'd probably need more like 5-6 years.
3-4 years of design work would be going from 003 to 004 CVN.
Going from "zero" would likely require 5-6 years or even more, of design work.
From what I have experienced, no, no and no. Its a recipe for disaster going this way. If you haven't got the reactor section locked down, and especially if you don't have any previous experience, then usually everything that can go wrong will go wrong. Your heat and mass balance, utility and electric load etc will cause extensive modifications that will take even more time. This is not mentioning all the unknown unknowns that tend to creep in. This is why nearly all fast tracked engineering of this type fails.
Plus the modular ship building works better the more mature the design. You can have a concept on how many modules etc, but everything inside that module at that stage is just a white box. Only after you get to 30 or 60% review then you lock down your module configuration and interface points, and it becomes something tangible to plan and build.
To be sure, there is definitely time and cost savings in there because the other subsystems are mature, and kind of already there, but it won't be nearly as much as people think if the key piece is being designed concurrently and any major change in it will cause significant knock on effects.
lcloo
Captain
If I remember correctly, the redesign of 003 from the original steam catapult to EMALS catapult took more than 1 year, refering to slayerhuahua in CJDBY. Thus for a complete ship design work, 3 to 5 years would be quite normal. I would not be surprise if work for 004 starts in 2016 or 2017, steel cutting in 2021 or 2022, and recognisable modules appearing in 2023 or 2024.
I highly doubt that IF though. The difference between a CVN and conventional CV is the reactor compartment and how you run the steam pipes to the turbine room. The hull structure will be designed around the pre-determined dimension of that reactor compartment. The impact to rest of the hull is not a big deal IMO.
This means that PLAN could have been designing their CVN in parallel to 003 many years ago.
Your assumption is that the dimension of the reactor is not settled. That is only if you don't determine the dimension from the very beginning. However, my thought is that the dimension of the reactor is a design specification of the reactor which is not allowed to be changed (enlarged), nor physically possible to enlarge. It is locked in the beginning and not allowed to be changed afterwards.
It is like I ask the engineers to design a sedan, the size of the engine is therefor determined. The guy will design the chassis and engine compartment in the fix size, the engine guy will do whatever necessary to fit the engine in it. Even if the engine guy has some difficulty, it is not the chassis to be changed.
Only about the bold texts.
It is a different story. Steam catapult runs its pipes through the whole ship from the boiler room at the bottom of the ship to the steam reservoir then to the top deck. EMALS only run cables. The switch demands changes to a very large part of the interior of the ship.
The reactor is replacing the conventional boiler almost in the same place, running similar number of pipes if not less around the same structure. The change doesn't go further than the compartment.
The extra work for switching to nuclear is therefor less. And this is still assuming a switch instead of parallel design of CVN.
Intrepid
Major
I expect that 003 and the future nuclear aircraft carrier were designed at the same time and the plans were drawn in parallel. I wouldn't be surprised if the future nuclear aircraft carrier was also initially designed for steam catapults and the design was changed to EMALS along with 003.
I think the nuclear reactors would certainly have been ordered 10 years ago.
I think the nuclear reactors would certainly have been ordered 10 years ago.
So, my view is that I think the PLAN had likely began designing their CVN a number of years ago, derived from the 003 design. Keep in mind the design of 003 would've been already largely set in stone years ago now, probably sometime after 2015, with only the minor redesign for the EM catapults.
In the case of the CVN, they could've started its design work (derived from 003) anytime in the mid to late 2010s.
I suspect the design of the CVN at this point, as of mid 2022, is likely nearly complete, if not complete.
.... However, I believe the design work for the CVN (again, as derived from 003) would've likely still taken a good 3-4 years.
Going from a conventional CV to a CVN is already a fairly significant difference, even if your hull was already designed around the dimensions of the reactor compartment. You'd still need to ensure that the rest of the hull's structure is adequately redesigned, such as ensuring you have sufficient berthing for how much crew your CVN now needs, ensuring that you can use up any new free space efficiently (such as more volume for aviation fuel, if any), slimming down the size of the island based on no need for an exhaust vent running through it given your ship is now nuclear... etc.
But we aren't just talking about going from a "conventional CV" to a "CVN". It is more accurate to say that they are going from "conventionally powered 003" to "nuclear powered 004".
That is to say, I think we should all expect 004 to have some significant differences and improvements over 003 (even if 004 is derived from 003), which would require substantial time for redesign/expansion:
- adding another catapult on the waist (for 4 catapults rather than 3)
- slimming down the size of the island and perhaps repositioning it to the rear
- redesigned flight deck including lengthening of the overall flight deck and ship length (which requires lengthening of the overall hull), and widening parts of the flight deck too, for better deck handling
- likely adding another elevator to the ship, namely on the port/aft position
And of course, all of the modifications in relation to adding nuclear propulsion:
- replacing the conventional steam turbines with nuclear propulsion
- electrical generation overhaul associated with said nuclear propulsion
- vents and piping modifications/removals
- redesign (or expansion) of ship's aviation fuel capacity
.... all of the above, for a notional 004 derived from 003, is not something that I can see take less than 3-4 years.
Reactor dimension is just 1 part of the puzzle. Once the dimension and layout is locked, there is the problem that more of the work is in the changing utilities / cooling / E&I demand, as well as the new pipe / cable tray runs etc. E.g. if you design asked for 150mm tray, so you allowed for 200mm tray, but the mature design needed 250mm tray cause you have a few more cables to run, then its not as simple as just bumping it to 250, you got run the clash checks through the whole lot, and reroute if needed. Now do that for every subsystem. (Maybe ~10,000 which any link to the reactor)
Using your example, you are designing 1 for a 100kw IC sedan, but now you want a 100kw electric / hybrid sedan, its a totally different story. Where are you going to put the fly wheel & the extra batteries that wasn't on the IC sedan?
My point is that even if there is 003 as template, changing it to a CVN design without the reactor component frozen is not going to be an ideal engineering scenario. It is pretty much the same as designing from scratch, except you can take the other mature subsystems like they are off the shelf to make those portions quicker. It still won't reduce much time as most of the time they are done concurrently and the reactor section is always gonna be on your critical path affecting your cost and schedule.
Just wanted to ask why you reckon these two in particular would potentially be in the cards for the eventual CVN, when these features aren't -
1) exclusive to whether the boat is nuclear or not, of course; and
2) necessarily beneficial to the PLAN's particular modus operandi on carrier operations, in contrast to that of the USN, esp. when the PLAN could've likewise opted for 4 cats and 3 lifts on 003 in the first place yet they had elected not to anyway?
I would say a better question is -- do we think that the configuration of 003 (leaving aside propulsion) represents the exact "final endgoal configuration" that the PLAN would be content with mass producing for the next few decades, or whether there are aspects of 003's configuration that was limited by certain factors (such as propulsion system type, the limitations of the conventional propulsion system that they are capable of designing and adapting to 003, power generation for catapults, and risk reduction)?
To answer your question:
No, of course those factors are not exclusive to whether a carrier is nuclear powered or not (given Kitty Hawk class and Forrestal class has those features in one way or another despite being conventionally powered), however in the case of 003, various factors such as technological limitations (risk reduction from both design and technological pov as well as limitations of power generation for EM catapults) are likely reasons for why they didn't go for a 100,000 ton carrier with 4 catapults and 3-4 elevators.
The reason they "didn't elect to pursue such a ship for 003", I suspect was partly out of choice and partly out of necessity/conservatism.
Pursuing such a large ship as their first wholly indigenous CATOBAR carrier would not only have been more technologically challenging and accordingly more complex and more ambitious, but it would have also placed higher demands on the conventional propulsion train (which they may not have been able to fulfill).
In contrast, for their inevitable CVN class, it would make sense to use the opportunity to realize a more optimized carrier design with substantially less compromises -- one that is worthy of mass production with a potential double digit production run in the long term.
The alternative, is that they decide to be even more cautious and iterative, and literally pursue a nuclear powered carrier based off 003's configuration, and then only pursue a larger and more optimized design after building one or two CVNs based off 003's exact configuration.
But if you're asking me whether the 003 configuration is one that is ideal for the PLAN? Certainly not. There remain a significant number of compromises. 003 is a massive advancement from CV-16/17, and puts it in spitting distance of the configuration of USN CVNs yes -- but there remains obvious changes and additions that can produce meaningful improvements.
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