(This is from http://infodump.thefifthimperium.com/en ... gton/286/1)At some point, navies have to strike a balance between survivability and numbers of deployable platforms. Manticore's preference has always been to err on the side of survivability when possible, which is one reason the jeune ecole's "pragmatic" willingness to accept attritional tactics (and the casualties which went with them) was anathema to the historical school. If you look at current Manticoran designs and doctrine, you'll see the merger of the two positions, with the original proponents of the jeune ecole continuing to lead in technological radicalism but with the historical school tempering their enthusiasm and generally knocking the "panacea-merchants" on the head at every opportunity. The BC(L) design will undoubtedly be further refined as defensive systems and doctrine mature and change, but that "step" on the operational (and tonnage) ladder will undoubtedly remain. The tonnage of the BC(L) is higher than the Admiralty would like to see, but it is probably the lowest tonnage range which will permit the balance between numbers and survivability Manticore is looking for. And it should also be pointed out, I suppose, that over the operational lifetime of a warship (particularly assuming that the Manties can revert to more of a peacetime stance), operational costs are going to enormously outweigh construction costs. The reason I make this point is that there is actually very little difference between the operational costs of a Nike and a Saganami-C. Oh, the heavy cruiser has some edge in the "affordability" department, but nowhere near as much of an edge as it has in the construction cost competition. This means that the economic advantages of the smaller, less capable type are nowhere near as pronounced as one might think. Procurement cost does have to be factored in when it comes to contemplating force mixes, of course, however, and that is where the Nike becomes more desirable than, say, a 4,000,000-ton design which would provide even more tonnage for survivability features and, possibly, permit an all-up MDM armament. The thing is that the Admiralty doesn't want an all-up MDM armament specifically because of the way it would drive up platform sizes (and costs) beyond those necessary for the mission in envisioned for the Nikes and their follow-on designs. (See the paragraph below.)
All of which also leads into your second point about the ammunition capacity of the BC(L). Ammo capacity is a part of the BC(L) design philosophy. A significant part, to be sure, but only a part. The BC(L) is intended to dominate in the face of anything below the wall, and with the increase in defensive capabilities and general all-around toughness, it's going to take something with all-up MDM capability and Manticoran-style laser heads to seriously challenge it. The type is intended for long distance, independent deployment, where ammunition resupply can become a problem; it's intended to stack quite large salvos, despite its limited (compared to a pod-layer design, at any rate) number of launchers, so it can get in a heavy initial salvo if it needs to; it already has Keyhole capability, and Keyhole is a major factor in defensibility; and it's designed for possibly running engagements with large numbers of individually smaller and less capable opponents (dealing with a LAC group, for example, or laying down the law to a "navy" of primarily light units which has crossed the line, like some of the Silesian systems were wont to do). The Saganami-C is actually more likely to disappear than the Nike, to be honest, because the Nike has more endurance and more toughness than the Saganami-C. That doesn't mean by any stretch of the imagination that the Saganami-C is going to simply vanish in the next six weeks, or the next six years, or possibly even the next sixteen years, but it means that the type will find itself being relegated more and more to secondary duties as the opposition's offensive capabilities improve.
From this forum (viewtopic.php?f=1&t=4892&p=121140&hilit=Saganami#p121140):
I should perhaps have said that something evolved from the Saganami-C would become the new CL equivalent. This is an area where thoughts are still evolving --- in my own thinking, as well as the RMN's --- so it would be a mistake to think that anything I've said above is the cast in stone word of God about How Things Will Be. My comments are more an analysis of how the situation is evolving and what the designers' constraints and options are likely to be/revolve around. I have some very definite idea of where the technology itself is going, but that doesn't automatically equate into what will prove to be the best way to implement that tech. To a large extent, that sort of thinking works its way out as I work on the books.
So, yes, the Sag-C is a transition type, but what it transitions into is likely to become the standard CL of the RMN. The "notional" 300,000-tonner may never go into production at all. On thing you can be pretty confident of is that warships aren't going to get a lot smaller. Assuming that you take DD tonnage as lying somewhere in the 100,000-120,000 ton range and you assume the same proportionate growth as that between a WW II Fletcher class DD and a Flight III Arleigh Burke class DD, your Honorverse DD would grow to 500,000-600,000 tons, which is moving you up towards something bigger than a Sag-C even for a DDD.
Frankly, I haven't made my mind entirely up, but I'm thinking the classic DD role/mission no longer applies and we'll be looking at simply deleting that class and going with a single cruiser niche below the Nike. I'm not saying that's the way things will happen, but the truth is that most of the DD/CL/CA screening roles for the battle fleet are nonstarters in an MDM/DDM universe. What is going to be needed is a platform that can be built in sufficient numbers to deploy everywhere you need it (which implies as cheap and small as possible) and yet remain survivable enough to do its job in peacetime and wartime alike (which implies not-cheap and not-small). As always, the designer's unenviable challenge will be to somehow reconcile those conflicting requirements.
While these aren't from the same time and may represent an evolution of ideas, I take it that a reconciliation is possible supposing that there will be (probably) one hyper-capable warship class smaller than the battlecruiser in regular service, that it's more likely more like a Saganami-C than anything else, but that the role and expectations of it will be more of a light cruiser than a heavy cruiser - more a scout and picket than a BC writ small.
The key changes, I think, will be the use of some successor of Keyhole I (specifically NOT Keyhole II) small enough for a 300-500 kton vessel to use effectively, and something to reduce operating costs particularly so that they are much less than the Nike's. But the role isn't going to be something to slug it out like a battlecruiser or heavy cruiser: it's going to be effectively what the light cruiser's role has been. It's something for commerce raiding, commerce protection, reconnaissance and system picketing, all with an emphasis on long-range operations, long-term deployment, and flexibility over sheer combat power.
Put another way: it's going to be all they're happy about with the Avalon now, but big enough to use Mk 16 DDM's easily and with fairly deep magazines and some smaller version of Keyhole I. Or a third way: it's going to be the smallest, least expensive, but genuinely effective long-range independent warship for the remainder of the 20th century PD.
So - what makes a Nike not much more expensive to operate than a Saganami-C? Sheer tonnage doesn't seem a critical factor: the Nike is five times the size but supposedly similar in operating cost. If sheer tonnage is no good indicator, I suspect crew complement would be the best with weaponry as a fair substitute. I don't have a crew figure for the Nike, but the weaponry count is close enough between the Nike and Saganami-C that I do think the operating cost may track weaponry pretty well. The Nike has 50 missile launchers, 64 counter-missile launchers, 84 PD clusters. The Saganami-C has 40 missile launchers, 20 grasers, 6 lasers, 40 counter-missile launchers, and 64 point-defense clusters. So while some of that five-fold increase in tonnage is going to weaponry and a little maybe to deeper magazines, almost all of it is going to sheer armor and sidewalls and the Keyhole system, plus possibly proportionately greater EW capabilities. At any rate, mostly it's built so much larger to be so much tougher, and that toughness isn't increasing operating costs much though it may increase procurement cost plenty.
So if the new light cruiser is going to be much more plentiful and cheaper to operate than a Nike BC, and it need not be remotely as dangerous or as tough as one, it looks like the place to reduce operating costs is with the weaponry more than anything else. You can do that with less weaponry, with less operating cost per weapon, or with both.
I think they can go for both, given the cruiser mission. Just reducing missile throughput increases time it takes to empty magazines (which is taken as an unalloyed good when RFC compares the BC(L) to the BC(P) - not something I can agree with, but he's representing BuShips any which way), and being able to sustain fire over several battles may be more important for that mission than being able to swamp defenses with a lot at a time. So as a light cruiser, a Saganami-C successor could afford fewer missile tubes, and as a unit needed in quantity, it needs anything that saves money and crew commitment over time compatible with its mission.
So suppose it halves the missile tubes to 10 per broadside, exactly as the Avalon has - and is considered adequate now having, despite those missiles not being dual-drive, off-bore-fire-capable, or possessed of the G killer warheads. The Saganami-C successor is still going to be about as large as the -C, particularly about as wide, so that's going to free up not only a lot of crew but a lot of volume. Since armor and other such passive defenses seem to be cheap in terms of operating expenses, let's suppose a lot of that tonnage goes there, and into the smaller Keyhole I variant. If it can't fire (or fire and control) nearly so many missiles at a time, at least it can expect to keep being able to fire them for longer.
The other big operating cost reduction I have in mind is a lot more radical, but given the nature of the mission and evolving RMN practice, I think it's got a shot at acceptance. The idea is to eliminate on-mount weapon crews for the missile launchers and grasers at least. They're only back-ups in case damage eliminates the ability of those weapons to fire from central control. I submit that that is not essential to the mission of the smallest effective warship. You would lose some ability to take mediocre shots under some damage conditions, all of which usually obtain, if at all, only when you're losing badly already. If you don't have to provide for those crews, you can fit in even more armor and protective measures, all of which will, when you do get into heavy combat, reduce the likelihood that damage will compromise that central fire control anyway. And back-up links should be easy enough with that spare tonnage, though that's maybe one place where the 1980's vision of the future on which the series is based diverges from a 2015 vision of it.
As a cruiser, and with the cruiser mission firmly in mind, it's going to need and get a good Marine complement. It will have the space for it, after all, but crew conservation will mean that the Marines are likely doubling as ship crew for everything they can be made to do without specialized training that doesn't have them needed somewhere else when they need to be a Marine specifically. If they're not serving as the crew for weapon mounts anymore, they'll still be valuable - maybe moreso - for damage control particularly, but also things like cooking and some assistance in sick bay.
The result is intended to preserve all the relevant virtues of the Avalon as a light cruiser and the Saganami-C as a DDM platform, while avoiding the obsolescent missile launcher type of the Avalon and the too-high operating costs of the Saganami-C for the workhorse light cruiser role. Production costs are likely to be nearly as high as a Saganami-C's, which is unfortunate but it's probably a bullet that the RMN will have to bite and it's going to cause less damage to their metaphorical teeth than paying to keep up the equivalent of 400 Nike's for policing second- and third-tier systems and every Manticoran trade route through so much space.