MDM light cruiser - just a Saganami-C without armor?

Weird Harold wrote:
Thanks for the textev, Vince. More Than Honor is "pre Great Resizing" and the explanation has been refined over the years.

My understanding is that after the Great Resizing, Mass-as-density lost a lot of ground to Mass-as-Displacement in the importance of Compensator efficiency. The textev implies that has always been true with the statement, "the size of the field is of very nearly equal importance."

The minor detail that "Mass-as-Density" and "Mass-as-Displacement" use the same units causes confusion. BTW, "mass-as-density" is an inaccurate term, but the mind isn't working at full capacity, yet this morning. An 8MT Freighter doesn't "Weigh" eight million tons, it Displaces as much volume as 8MT of a specified liquid of known density. (I don't recall the number used for The Great Resizing.)

I'm sure MaxxQ or somebody else from Bu-9 will correct me or refine the explanation.

The agreed to density was .25.

Mass was the most often referenced ship descriptor in the books prior to the great resizing, so it was kept as the main definer of ship sizes. everything else is just a loose association.

The compensator field is based on the volume being compensated, not the mass inside the volume, so empty freighters accelerate just as swiftly as full freighters, and warships with empty magazines cannot tweak their acceleration because they lost 100,000 tons, nor are they slowed if they stuff 100,0000 tons of pods inside the field.

Also, there are "fat" ships in the Honorverse (CLACS) with intentionally wider beams than normal, accepting a slower accel because they have a wider compensator field. The current warship design uses a optimized size of the compensator - you can make the compensator field in different shapes, lengths, and widths but those shapes and size ratios are less efficient than the current cylinder shape and ratio.

Some in the past have suggested making a Mk 16 CL by making a shorter SAG-C, with the same beam to allow for the mk 16's launchers, but less length so it had fewer launchers and mass. Because the beam is the same in the 2 designs, the compensator field on the CL would not have the same ratios as normal, making the stubby design only marginally faster (if any advantage) over the normal Sag-C.

Theemile wrote:The agreed to density was .25.

0.25 of what? The number is meaningless without a reference.

Weird Harold wrote:

Theemile wrote:The agreed to density was .25.

0.25 of what? The number is meaningless without a reference.

sorry. 0.25 that of water or .25g/cm^3.

Theemile wrote:

Weird Harold wrote:0.25 of what? The number is meaningless without a reference.

sorry. 0.25 that of water or .25g/cm^3.

I thought that was probably what was meant, but ISTR a mention of using the standard density of Alcohol (ethanol) as the reference.

The main point is that after the Great Resizing, "Mass" in reference to starships is a measure of volume (displacement) rather than "weight" or "density."

Theemile wrote:
The compensator field is based on the volume being compensated, not the mass inside the volume, so empty freighters accelerate just as swiftly as full freighters, and warships with empty magazines cannot tweak their acceleration because they lost 100,000 tons, nor are they slowed if they stuff 100,0000 tons of pods inside the field.

Though I assume there's some break point where actual mass becomes the dominant factor.

Presumably, since freighters of a stated mass don't seem to be wildly out of proportions to a warship of that same mass, the 'displacement mass' calculations for them are also done on an average density of 0.25 tons/m^3. But unlike warships it would be very easy to pack them with cargo dense enough to wildly distort that average tonnage.

If an 8 mton freighter actually massed 8 million tons when full of cargo averaging 0.25 ton/m^3, and we assume that 1 million tons is empty ship tonnage, that implies it has 28,000,000 m^3 of cargo space.


Here's what that ship's actual tonnage would be if that volume of cargo was filled with some reasonably common materials: water (1.1 tons/m^3), iron (8.66), lead (12.47), or tungsten (21.18)

Water: 1 mton + 1.1 ton/m^3 * 28 million m^3 = 31.8 mtons
Iron: 1 mton + 8.66 ton/m^3 * 28 million m^3 = 243.5 mtons
Lead: 1 mton + 12.47 ton/m^3 * 28 million m^3 = 350.2 mtons
Tungsten: 1 mton + 19.25 ton/m^3 * 28 million m^3 = 596.0 mtons

At some point along that progression I have to think the acceleration would fall off. You might be able to get to water without accel impact but I seriously doubt you could get past 2 or 3 tons/m^2 before it started impacting accel. That would be 8-12 times the nominal density!

Weird Harold wrote:The main point is that after the Great Resizing, "Mass" in reference to starships is a measure of volume (displacement) rather than "weight" or "density."

Correct.

As to the earlier question of armor, a Star Knight CA has about 2-2.5 meters of armor at the centerline of the broadside, tapering to less than .5 meters at the upper and lower "corners". Dorsal and ventral surfaces have about 10-15cm of armor.

Quite some time ago (I don't remember where exactly) there was mention of a 'notional 300kt light cruiser' as the hypothetical new vessel to, in the age of the MDM, fulfill the 'light cruiser' ship bracket - that is, a ship with not just more firepower and defenses than a destroyer, but more importantly more endurance and versatility.

I don't think it would be based on a scaled-down sag-c, though. It was stated in Shadow of Saganami that "Nothing smaller (or older) than a Saganami-C-class ship would ever be able to handle" mk16 DDMs - the Roland gets around that with the hammerhead cluster arrangement, but I think it's safe to say that a sag-c probably represents the smallest ship that can handle them as *broadside* armament. And as noted, a lighter ship with the same beam as a sag-c would not be any faster than a sag-c, so it wouldn't make for a very good CL.

Rather, I think a hypothetical ~300kt mk16-armed CL (an 'Avalon-B', for lack of a better term) would probably be based on a scaled up Roland (188kt). You could scale up the armament a bit (8 tube clusters instead of 6?), but most of the extra tonnage would probably go into defenses, ammo, and crew space for a marine complement - i.e. the places where a Roland's laser-focused 'smallest viable mk16 platform' design leaves it lacking. I had somewhat of a discussion on this topic with a few others in a thread last year.

MaxxQ wrote:As to the earlier question of armor, a Star Knight CA has about 2-2.5 meters of armor at the centerline of the broadside, tapering to less than .5 meters at the upper and lower "corners". Dorsal and ventral surfaces have about 10-15cm of armor.

On a completely unrelated topic - am I allowed to ask for length/diameter dimensions on the various missile types you've rendered, or is that info you can't give out?

Another way to look at mass of SAG-C

480,000tons
1200 MK16(30 salvos from 40 tubes)
MK-16 = 94ton
~~~ 25% of the mass of a SAG-C is missiles.

Does not count the ammo storage launch tubes etc even before we begin to talk defensive systems or power systems.

Armor? Primary Armor in the HV are its SIDEWALLS people. Its physical ablative, and crush zones are secondary and tertiary armor. So, in essence, when you say "remove" SAG-C armor(we don't know how massive/redundant) Sidewall generators are(actually I think we do know the redundancy factor), we are actually describing removing sidewall strength/redundancy, not necessarily as much physical armor. After all we still need the ships hull to be structurally redundant due to the simple fact this is space and we need air tight compartments for human survival.

Somewhere over at thefifthimperium.com you can find a very crude ditty of DW's stating that each impeller end including W-sails, hypergenerator, compensator equal ~15% Volume(and tonnage) each end.

So, we start with a rough 30% JUST for propulsion. Then add living quarters, fuel, boat bays, drones etc and we are talking 40~50%.

So, you might noticed where I slyly went... If Offensive tonnage requires ~25%, and basic "ship" functions require 50%.... That leaves 25% for defensive functions be it CM's, ECM drones, PDLC, GRASERS(which I consider defensive in an MDM universe) or armor in all of its 3 forms.

So, offhand if you "only" removed SAG-C's armor, then it will lose 10-->15% of its tonnage volume. Of course even a DD has sidewalls so.....

Great, your MDM CL(all things being equal to SAG-C offensively) will mass around 400k-->430k tons.

Why bother?

MuonNeutrino wrote:On a completely unrelated topic - am I allowed to ask for length/diameter dimensions on the various missile types you've rendered, or is that info you can't give out?

Sure, you're allowed to ask...

Seriously, though, I think this question has been asked before, and my answer then was that the scale comparison figure I include in all my renders is 180cm tall. Knowing that, and accounting for perspective distortion, someone (I forget who) calculated the rough dimensions of a couple of the missiles.

Sorry I can't be more detailed than that.

Weird Harold wrote:
DDMs (Mk-16Gs) are still a lot better than the ERMs/LERMs of the Avalon class.

pappilon wrote:
IMHO, The CL is going the way of the frigate.Between the Roland class DDs and the Saganami "C" CAs here is no mission parameter for the CL, it is squeezed out.

Dauntless wrote:I'm not so sure that the CL as a platform is gone.

the main difference as i recall between a DD and a CL has always been rather small. the CL was a basically a slightly bigger DD, with a slightly bigger weapons load (8 tube broadside to a DD's six and graser in place of laser mounts) and more importantly combat endurance. basically the extra mass tended to used for deeper magazines and a biger marine detachment.

personally I believe a roland stretched out to 250/300K with the same sort of armament layout of maybe 8/10 tubes as chase weapons, 5 grasers in the broadside and more life support for the marines would work just fine for a DDM CL. call it the Fearless class of CL

it could be argued that in peacetime the Roland doesn't do enough as it will struggle with the anti piracy that was (and in all likelihood will be) that was a bit part of a DDs duties pre war due to its lack of marines and small magazines.

I suppose, in the era of BF running commerce raids, a task group of 3 Rolands and a CL wold work for convoy protection. And if one was into a bit of privateering the Cl would work wonders.