Shipbucket

ah, you can't actually directly use the design for the layered satcom antenna for radar as they're using a passive array w/ no phase steering (ie. mainlobe is along antenna boresight axis) since they are using a layer of common feed lines to the crossed loop/dipole quadrants to minimize blockage... to get beam steering by phase variation you'ld need an independent feed to each crossed/loop dipole radiating element w/c would increase blockage by the transmission/feed layer... w/o the phase variation for steering you'ld be effectively limited to a pencil beam cone w/ mechanical steering...

(and apologies for the tech OT)

OK, that is what I feared, an independent feed to each array is not feasible within such a volume. But thanks a bunch for confirming it and explaining it more clearly than I ever could.
We can cut the OT for now then.

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Soviet Century/Cold War 2020 Alternate Universe: Soviet and other Cold War designs 1990-2020.
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As far as I am concerned, no sort of tech talk is ever off-topic in my drawing threads!

As usual, pretty minor changes. Artistic revision, mostly.

A list that is not necessarily all-inclusive, and definitely is in no real order:

• Slight bow revision. Moved the line-handling spaces down and back slightly, and more importantly went to two beam anchors rather than one beam and one bow.
• Redrew the Furuno nav sets, relocating them slightly.
• Redrew all of the minor air intakes, for maximum angleness.
• Replaced the small AMDR-X on the after superstructure with 6' AMDR-S arrays. Removed the aft-facing small AMDR-X. This is better for search, and now all S-band arrays are 120deg configuration, and all X-band arrays are 90deg. ESSM is going to be all-active at some point in the near future, so I'm not too worried about losing illumination capability aft.
• The HF whip right aft has been replaced with a third OE-538. These are specifically for subs, so why not use a submarine-like retracting antenna at the back end of the flight deck?
• Woooo we have a ship's bell now! Figure it'd be relocated into the mast while underway.
• This is a bigger one -- we probably have VLS UNREP capability now. There's space for a hangar under the forward satcom for an IC-40 crane with a 4.5 ton lift, which theoretically is borderline maybe enough for full Mk 57 canister lift. If not, it's definitely enough to lift anything up to and including Tomahawk/SM-ER. This is sort of a big deal. I presume the actual crane used would be compressed as much as possible, and would run a winch-cable down to a padeye on the deck when lifting. Ships are wobbly. If we actually carry cranes, we need to carry two. I don't see any way for one to get from the forecastle to the flight deck.
• Is the inflatable decoy the right size? I have no fucking idea! I handwaved about a 5m side length based on some shots of it being pulled by a 7m RHIB. I scoured the net for anything better, to no avail. I'd be curious if anyone knows how big they actually are. Apparently the USN tested a variant that was basically Mk-46-sized, so I'm just using an additional pair of Mk 32 to handle these.

And here's another bigger deal! For those who want to hate on the magical power of magic fusion, we've finally got a dino-burning version. Three LM-2500+G4 in the forward machinery space, two on the keel and one on the main deck level. The two RR4500 stay forward, for about 98MWe total (cf about 80MW for Zumwalt). The big penalty, aside from range, is that we can't carry four big helos anymore. We can carry two AW101-size helos and four TEU per side, or an 11m RHIB, or something on that order. This is still pretty great, just not nearly as awesome as the fusion monster.

Neat. They're getting more and more refined each time!

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AU Projects: | Federal Monarchy of Tír Glas| Other Ivernic Nations | Artemis Group |
Blood and Fire

Still looking awesome, as if that needed to be said

Couple of questions/thoughts about your two big deals:
1) I understand that your reload crane would be located beneath/before the forward satcom dome, i.e. just aft of the gun turret. Does it somehow have enough span to cover the full VLS array? Or are only the rearmost half of the VLS packs considered reloadable underway (still better than nothing)? Is the yellow ladder forward of the main gun a retractable UNREP post, and if so, dies it help in the operation? Also, do you plan your aft VLS cells to be reloadable as well? If so, you probably just need some kind of telescopic overhead crane that can also assist in container loading and helo maintenance.

2) Wasn't the fusion plant supposed to be extra compact in the first place, and if so, what did you move around to fit the turbines, the fuel and the stack? Or have the further redundancies and accessories tacked on along the way taken enough space that you can just swap power packs around?

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1) Oh goodness lol. I did not communicate well. When I say a hangar for a crane, I mean literally there is space for a commercially available crane that would drive out and plant itself next to whatever cell is to be reloaded, winch down for positive deck contact and then reload the cell, moving down the deck as needed. This is a larger variant in the mfg's series, but it's illustrative.

In practice, I suspect you'd go with a bespoke solution that would look halfway between this unit and something that would glide down the prominent deck rails on legacy Soviet hulls. The ladder-looking thing is for forward UNREP of VLS, yes.

I figure you'd at least have the capability to carry a second crane in the main mission bay to reload the aft VLS cells. It's not like we don't have the volume to spare. Probably a fitted-for-not-with situation in practice, I guess if you were really desperate you could probably have the comical solution of using a Merlin to move the crane from the forecastle to the flight deck.


2) There are four answers here, given in approximate order of nuance.

• We lost about a third of the mission bay to uptakes and to the main deck level LM2500.
• The fusion variant is hilariously overpowered, more than double the generating capacity of the dino-powered version. At some point I saw promotional materials from Lockheed saying 100MWe on the back of a semi (hence going with a 40' TEU to indicate the plant), but it's not obvious that you can necessarily shrink the plant further than this. I'd absolutely love to have a pair of 50MW reactors in 10m compartments rather than 100MWe in 15m, but I'm not sure what Lockheed engineers might think the lower limit would be on practical plant size. I stuck with what they gave me.
  
  (yeah, they might have meant a 53' oversize unit, but I can drop two 40' units side by side and feel just fine)
• The fusion variant has way more conventional power generation than any nuclear ship the USN ever built. The reason for this is that a fission plant is always itching to get up and go. Withdraw some control rods and the thing is basically self-starting. It has well-known and well-understood shock resistance. Finally, the minimum power output from the reactor is very low.
  
  None of these things is necessarily true of the fusion plant. It must surely require some sort of active power input to get the EM field structure in place, and I worry that the ~8MWe (plus whatever batteries for transient load) from the two RR4500s might not be enough to get the thing started. Its shock characteristics are completely unknown. Finally, it's not obvious how low a power setting you can run at. We might need to run on gas turbine generators when transiting ports and the like, lest we need huge power resistors into which we can dump a bunch of excess heat into seawater when we want to go slow. We might need to do both, it wouldn't shock me if these fusion plants were unable to operate at less than, say, 30MWe.
  
  So we end up losing some of that compactness to the fact that this is really a COGAF plant (let's not write it the other way around).
• "Compact" was always issued in the context of land power generation, which obviously has hugely relaxed volume requirements. This is Kawasaki's 30MWe industrial gas turbine, roughly comparable to the LM2500+G4, and it's clearly a much bulkier creature.
  
  Might the "compact" fusion plant be something that could be made even smaller (or at least less long and skinny) for shipboard use? I'm almost certain it could, but what are the internal dimensional drivers? I have no idea.

OK, thanks a lot for the details.

1) My bad, didn't cross my mind to check the reference of the crane. I guess my mind went straight from "VLS UNREP reload" to "strikedown crane" and skipped straight over the idea of having a carrier-deck vehicle tooling around on the fore deck of a destroyer.
The idea of a countersunk rail track for the crane is alluring, and might even lead to a tramway-like rail power feed that would reduce the mobile weight of the crane.
Just to make things more difficult: wouldn't it make sense to carve out a crane-size gangway between said hangar and the mission bay? How would that impact the bridge layout?

2) That matches more or less my view of the situation, except obviously much, much better researched.
So, to summarize my newly enlightened understanding :
- Yes, the CODAG propulsion takes more space than the fusion one, if only from the stack
- No, the fully equipped COFOG (works too, right?) propulsion system isn't that compact once you add all things safety- and backup-related and as long as you stick to the originally proposed fusion plant without a major redesign
Did I get that right?

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Soviet Century/Cold War 2020 Alternate Universe: Soviet and other Cold War designs 1990-2020.
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You know what, hell, we probably can have a ramp up to the forecastle from the hangar. That's pretty awesome and I ought to have considered it. Note this crane is a bit less than 7' tall and 6' wide, so something like 9x8 (which I can totally fit) allows seriously awesome access forward and aft. We can start thinking about crazy stuff like launching Scan Eagle forward while conducting flight ops aft, stuff like that. The crane can handle 24deg changes in concave slope and we can curve the convex edge, so as to fit the entire ramp within a single compartment.

I'll draw it properly later, maybe, but this is IC-40 to scale, with the ramp and whatnot. We could probably even fit an IC-80 without too much trouble, which has a 18klb capacity.

THIS, in turn, might open up some questions about how I want to arrange the cranes within the mission bay, doesn't it? And now we can reasonably have major VERTEP forward when we want to do so.... this is a huge win. Major improvement, thank you for the suggestion.



Regarding fusion stuff, yeah, that's basically as much as I know. I think we're probably nowhere near optimum, but whatever. It's just shipbucket

Also note I'm exploring 2x2 Wartsila 6L26 for about 2MWe each, the after pair conveniently in the same compartment as the aft azimuth thruster. I'm going to notionally claim that we can carry enough batteries (lead-acid for shielding and ballast, if nothing else!) in each reactor space for a cold-start. Thus I need less peak conventional generating capacity to get these started up, and I can split the plant. Critically, we are now survivable against a single hit that knocks both fusion plants offline and destroys the forward AMR, a weakness of the previous configuration. I also didn't like the prospect of exhausting a gas turbine onto the forecastle in heavy weather, although I know real ships do this. Same total auxiliary power generation capacity, but more survivable and more efficient. Louder, I'm sure, but you can't have everything.

We retain 2x2 Cat C18 at 550KWe for emergency use; I understand this to be the emergency diesel generator of the Zumwalts. These are right aft and in the forward azimuth thruster compartment. I've read too many horror stories of rarely-exercised diesel generators crapping out when called upon in an emergency, hence doubling up of all units. All diesels exhaust at the waterline, which isn't strictly optimal in bad weather but none of these should be regularly operating in bad weather.

That's cool, glad you like it
Honestly, I hadn't paid attention to the deck shift and the need for a ramp. If there is space for a gangway, I don't see a reason this can't work. You might even hard-build some enclosed parking space for three cranes to service both aft and fore decks at the same time. Missiles notwithstanding, they can probably help a lot with solids UNREP, moving palettes quickly away from the reception point. Hell, you can even imagine them carting around specialized equipment to pre-equipped plug-in stations. Say, specialized sensors (SLAR, ELINT...) or weapon stations (Griffin palettes, miniaturized RMS...) or whatever (UAV catapult) could be carried one at a time to reduce cost, and deployed in a specific corner of the deck when needed. Or is this starting to sound too LCS-y already?

Also, I mentioned before the idea of a bespoke rail-driven trolley replacing the wheeled crane. Though it certainly sounds dangerously un-American compared to the truck-based version it opens a different avenue for expansion where you would lead the rails to a holding bay where you could swap trolleys via overhead crane with a selection of crane (utility) and palette (cargo) trolleys which can then load one another with pre-packaged modules (see above) to then position then all around the ship on plugs or stick them on the rail circuit and feed them in place through the rails. With position sensors on the rail and optionally some COTS remote-sensing between trolleys, you can remote-control all that from a central console in the hangar.
In your VLS UNREP scenario, you would move a heavy-duty palette trolley and a crane trolley to the edge of the hangar bay. The crane picks up the VLS canisters, piles up as many as possible on the palette, then both follow the rail to the designated VLS module, where the crane unpacks the individual canisters and strikes them down in place, until the palette is depleted and both trolleys switch back to their storage station. For deployable systems, you load them on palette trolleys from an overhead crane directly at the trolley station or at a designated loading bay, and then drive the loaded palette to the designated plug station, which can consist in a rail derivation (so as not to clog the main circuit) where the palette sits snugly with its system on top and handles the power feed and diagnostic.

The possibilities are endless! And I really shouldn't get that excited about a glorified warehouse sorting system!
I'll give a stab at drawing this version at some point, but it is clearly time for me to turn in now.

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Soviet Century/Cold War 2020 Alternate Universe: Soviet and other Cold War designs 1990-2020.
My Worklist