Citadel-class Assault Ship design

[Major B]

I’m finishing a new design for an Imperial Navy Assault Ship. The full page craft profile is posted here and the design worksheets are posted here.

The idea was spurred by discussions in this forum about planetary invasions. What I set out to do with this design was to figure out what all needed to be packed into a ship to get a battalion of jump troops to where they were needed, put them on the surface, and support them while in action.

It was easier said than done, so I’m going to lay out some of the considerations and trade-offs that are part of the design in this thread. I hope it will assist others crazy enough to look at the complexities of a surface invasion.

And I’m working on deckplans now so I’ll appreciate any feedback that can make the final product better.

This is the MT-format UCP (short version):

[FONT=Calibri][B][I][U][FONT=Calibri]Citadel[/FONT][/U][/I][/B][B][U][FONT=Calibri]–class 7,900-ton Imperial Armored Assault Auxiliary TL15 version 1.01 [/FONT][/U][/B][/FONT]
[FONT=Calibri][FONT=Calibri]     [B][U]CraftID[/U][/B]:    Citadel-class Medium Auxiliary, Armored, Assault (MAA), [U]TL[/U] 15, [U]MCr[/U] 4,1[COLOR=red]71[/COLOR].[COLOR=red]140[/COLOR] [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       (MCr 5,7[COLOR=red]85[/COLOR].[COLOR=red]95[/COLOR] with carried craft and vehicles)[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]           [B][U]Hull[/U][/B]:    7,110/17,775; [U]Displacement[/U] 7,900 tons, [U]Configuration[/U] 4SL, [U]Armor[/U] 58G, [U]Loaded Wt.[/U] [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       143,[COLOR=red]257[/COLOR] tons, [U]Unloaded Wt.[/U] 109,[COLOR=red]78[/COLOR]8.[COLOR=red]6 [/COLOR]tons[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]      [B][U]Power[/U][/B]:    5[COLOR=red]18[/COLOR]/6[COLOR=red]90[/COLOR]; [U]Fusion[/U] [COLOR=red]92[/COLOR],[COLOR=red]892[/COLOR].8 Mw, [U]Duration[/U] 5.[COLOR=red]4[/COLOR]/16.[COLOR=red]2[/COLOR][/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]         [B][U]Loco[/U][/B]:    854/1,138; [U]Gravitic Thruster[/U], [U]Maneuver[/U] = 3; [U]Agility[/U] = 0[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       534/712; [U]Jump[/U] = 4[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       [U]Top Speed[/U] = 4,200 kph, [U]Cruise[/U] = 3,150 kph, [U]NOE[/U] = 190 kph[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]      [B][U]Comm[/U][/B]:    [U]Radio[/U] System (3), Far Orbit (3), [U]Laser[/U] System (2), Far Orbit (3), [U]Maser[/U] System (4), [/FONT][/FONT]
[FONT=Calibri]                       [FONT=Calibri]Far Orbit (5), [U]Radio Jammer[/U] Far Orbit (2)[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]    [B][U]Sensors[/U][/B]:    [U]EMS Active Array[/U] Far Orbit (4), [U]EMS Jammer[/U] Far Orbit (2), [U]EMS Passive Array[/U] [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Interstellar (6), [U]Low Penetration Densitometer[/U] 250 m (6), [U]Neutrino Sensor[/U] 10 kw (6); [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       [U]ActObjScan[/U] Routine, [U]ActObjPin[/U] Routine, [U]PassEnScan[/U] Simple, [U]PassEnPin[/U] Routine, [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       [U]PassObjScan[/U] Routine, [U]PassObjPin[/U] Routine[/FONT][/FONT]
[FONT=Calibri][B][FONT=Calibri]            [U]Off[/U][/FONT][/B][FONT=Calibri]:    [U]Meson Gun[/U] 04x, [U]Beam Laser[/U] xx7, [U]Missiles[/U] x06[COLOR=red], [U]Fusion Gun[/U] x05[/COLOR][/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Batteries        1                             3                      [COLOR=red]5                             6[/COLOR][/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Bearing           1                             3                      [COLOR=red]5                             6[/COLOR][/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       40 battery-rounds (BR) of HE missiles, 5 BR of nuclear missiles, battery round = [COLOR=red]90[/COLOR][/FONT][/FONT]
[FONT=Calibri][B][FONT=Calibri]           [U]Def[/U][/FONT][/B][FONT=Calibri]:    [U]Defensive DM[/U] +8, [U]Armor DM[/U] +6[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       [U]Sandcaster[/U] xx6[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Batteries        6[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Bearing           6[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       45 battery-rounds of sand canisters, battery round = 54[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]    [B][U]Control[/U][/B]:    [U]Computer[/U] model 8/fib with two backups, [U]Large Holodisplay[/U] 6,[U] Holo HUD[/U] 30, [U]Holo[/U][/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       [U]Linked Control Panels[/U] 36, [U]Electronic Circuit Protection[/U], Basic Environment, Basic Life[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Support, Extended Life Support, Artificial Gravity, Inertial Dampers, [U]Air Locks[/U] 22[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]      [B][U]Accom[/U][/B]:    [U]Crew[/U] 1[COLOR=red]49[/COLOR] (8 segments of 19), [U]Bridge[/U] 11, [U]Engineering[/U] 11, [U]Maintenance[/U] 2, [U]Gunnery[/U] [COLOR=red]29[/COLOR],[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       [U]Flight[/U] 56, [U]Ship’s Troops[/U] 21, [U]Command[/U] 12, [U]Stewards[/U] 4, [U]Medical[/U] 3, [U]Crew Staterooms[/U] [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Single Occupant Large = 2, Single Occupant Small = 14[COLOR=red]7[/COLOR], [U]Passenger Staterooms[/U] Single [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Occupant Large = 2, Double Occupant Small = 224, [U]Low Berths[/U] 45, [U]Subcraft[/U] 8 Pauldron[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       Fighters, 8 Limber Shuttles, 12 Fleet AFVs, 3 Swift APCs, 12 Prodromoi CRVs, 8 Dasher [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       GPUVs, 4 Titan AMRVs, and 1,155 Drop Capsules[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]       [B][U]Other[/U][/B]:    [U]Cargo[/U] 12,[COLOR=red]150[/COLOR] kl (9[COLOR=red]00[/COLOR] displacement tons), [U]Power Plant Fuel[/U] 6,0[COLOR=red]15[/COLOR].[COLOR=red]97[/COLOR] kl, [U]Jump Drive[/U][/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       [U]Fuel[/U] 32,684.3 kl, [U]Craft & Vehicle Fuel[/U] 691.8 kl, [U]Object Size[/U] Large, [U]Emission Level[/U] Faint[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri][B][U]Comments[/U][/B]:    Excerpt from the 1112 edition of [U]Jane’s Fighting Ships of Known Space[/U]: "The Citadel-[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]class assault ship combines the functions of a craft carrier, troop carrier, and fire support vessel and [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]is intended to spearhead planetary assaults. Despite their impressive armament, the vessels are not [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]classified as combatants. They are included in the ranks of the Imperial Naval Auxiliary Fleet and are [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]considered to be a choice assignment among Auxiliary Fleet officers and other ranks. In peacetime [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]these vessels routinely undertake patrol, training, and flag missions and serve as a deterrent in [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]border areas as well as areas prone to unrest. In wartime, they will be found in the forefront of [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]assault task forces."[/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]                       "The service record of the Citadel-class, though brief, is nevertheless exemplary. Of [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]the first eighteen vessels commissioned, four saw service in the Fifth Frontier War and two [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]([I]Redoubt[/I] and [I]Bulwark[/I]) received commendations for actions in the counteroffensives against the [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]Sword Worlds and the Zhodani in 1109. Another (the [I]Safehold[/I]) served notably in the emergency [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]response to a local plague on [U]Uakye[/U] (Spinward Marches, 1805) in 1111, also earning a [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]commendation from Archduke Norris. Twenty-one vessels of this class are now in service and the [/FONT][/FONT]
[FONT=Calibri][FONT=Calibri]IJEB has allocated funding to procure as least 30 more in the next decade."[/FONT][/FONT]

 

[Major B]

Design Preliminaries

To build the ship, I first had to figure out how big the assault battalion would be. These are drop troops for the most part. I figured they would need some armor for recon and close support but no organic heavy indirect fire weaponry as they should be able to rely on ortillery and fighter support from the fleet. They could also get by with somewhat smaller headquarters personnel at company and battalion level (their missions are complex but should be of short duration and planned in detail). IMTU, Imperial Marines do not all have battle dress and FGMPs, but the Line Marine Assault Infantry battalions definitely do have them. These are shock troops organized for short but intense action, so they are almost all tooth with very little tail. They are used in the initial stages of an assault, and then usually withdrawn to form an orbital reserve. If employed for longer duration missions, they should be augmented with additional support units to mitigate the organization’s lack of dedicated support structure and staff.

I settled on battalion strength of 450 – three infantry companies of 120, an armor company of 65, and a battalion headquarters of 25 (the TOE is posted here and here). The infantry structure is standard for marines IMTU; squads are composed of two fire teams with a squad leader, platoons have three squads, and companies have three platoons. One of the three infantry companies is equipped with grav belts for added mobility. The armor company has three platoons of four tanks each plus a recon section with twelve small one-man recon tanks. It has organic lift for all of its personnel; leaving 385 troopers who need either drop capsules or shuttles to get to the surface. Even if shuttles aren’t needed for insertion, they will be needed for extraction. Also, the armor company needs to have bay space for twelve 5.6-ton tanks (UCP here), three 7.7-ton personnel carriers (UCP here), twelve 2.64-ton recon tanks (UCP here), eight 2-ton utility vehicles (UCP here), and four 10-ton maintenance/recovery vehicles (UCP here).

Since these are the troops that lead an invasion, I looked hard at the best way to get them to the surface. Shuttles are needed for extraction after the mission, but since these are the troops sent in to clear a landing zone for later troops brought in by shuttle, they are most likely to be exposed to effective defensive fires. Drop capsules for insertion are a great benefit to survivability because each enemy defensive fire hit will only eliminate one trooper rather than a shuttle carrying a squad, platoon, or more. To launch the entire battalion (less the armor company) at once requires 385 drop capsules, but they don’t all have to be launched at once as long as the time interval between volleys is not too long. With 55 launchers (each holding one capsule) and six capsules per launcher in a ready rack, the entire force can launch in three minutes (30 seconds between volleys). At least two drop capsule reloads should be carried (in addition to the one set carried in the launchers and ready racks) so more bay space will be needed for them. Each drop capsule is half a displacement ton so 385-tons of spare drop capsule storage.

To extract the troopers when it is time to return to the ship, I needed some carried craft. I first considered using the Caisson (50-Td Assault Shuttle) I built for the Wind-class Strike Cruiser as it can carry up to 54 fully-equipped troopers (roomy seats). But I thought it would provide more flexibility to have a larger number of smaller shuttles, so I designed a 20-ton craft (UCP here) that can still transport a full platoon of 31. But the shuttles should have fighter protection (plus the marines would find the support useful), so I also built a 20-ton multirole fighter (UCP here). Ideally there will be a carrier supporting the assault but the world (or the universe) isn’t always ideal plus including the fighters gives this assault battalion capabilities similar to a US Marine Corps MEU which is a good model for the types of missions I see the Imperial Marines tackling.

Last but most important and most often neglected – supplies. IMTU, Line Marine units carry 90 days of supplies with them. Honestly though, I didn’t do any in-depth analysis to figure this part out so if anyone has a more refined estimate, please share. I assumed two-thirds of a displacement ton per trooper per month (or two tons per trooper to cover three months). That means at least 900-Td of cargo space on top of whatever the ship needs for sustainment.

So, just to accomplish the mission I outlined at the start, I needed a ship with room for all of this stuff, billeting space for 450 plus the regular crew, weaponry to support the troops on the surface and defend the ship, and it should be able to keep up with the fleet (meaning J4).

I plan to bring up some of the tradeoffs and design decisions I made in future posts if there is interest, but this is all I have written so far. Please let me know what you think and if you'd like more information on the design. In the meantime I'll keep working on the deckplans.

 

[McPerth]

I whould like to know what the asterisks folowing duration mean. I assume that they mean duration is on full combat power, as less that 7 days duration means it won't last a jump. If so, you should please tell us the equivalence to non-combat days.
Also, if you accept suggestions from this newbee, in MT designs I always preferred the fusion gun turret to the lasers, most so if you don't intend to engage long range protracted boardsides. A fusion gun uses the same power than 2 lasers, but gives you factor 5 battery at TL 14-15 (MT errata), so has the offensive/antimissile power of 6 BLasers or 12 PLasers and has a +2 to penetrate sandcasters.
The drawbacks of needing double volume per turret and price are offset by the need of half (for BLasers) or a quarter (PLasers) that many turrets, thus resulting in same (or even less if PLasers) volume and less power, weight and price (and so CP and crew) for the same battery power. The only true drawback that leaves is his limited range to planetary (50 KK), more than enought for defense or planetary bombardement/ground support.
This is not true if you intend to have batteries with more than 5 power, as is your design, but perhaps 15 level 5 fusion batteries whould give better fire support to the dirtside element than your 3 level 7 laser batteries ( I assume you used BLassers).
I hope you won't see me as too daring for this suggestions on what seems a good design.

 

[Gray Lensman]

Sweeeet!

I reviewed all of the designs again and I must say that you sir, have put together a Very Fine piece of work.

Next you are gonna do the entire strike group right? :rofl:

NO! Put down the gun dude!

I especially like the CRV design and the fact that you didn't overlook the maintenance/recovery assets.

Having been in Armored Reconnaissance myself it looks really good. but I would consider having one or even two extra 20 ton shuttles devoted to Medevac?

 

[Major B]

Having been in Armored Reconnaissance myself it looks really good. but I would consider having one or even two extra 20 ton shuttles devoted to Medevac?

Thanks Dan. Coming from someone with your experience, the compliment means a lot.

I thought about shuttles for medevac and they can do it when the troop seats are pulled out, but I thought they'd be vulnerable even with their armor. I see the Dasher filling in until the tactical situation allows the shuttles to come in. That's one of the reasons I made them so fast.

I think you had in mind something more than just evac but a craft that brings some treatment and triage capability with it. Those are going to be carried on the hospital ship that I'll build after I've finished the rest of the strike group.

 

[Major B]

I whould like to know what the asterisks folowing duration mean. I assume that they mean duration is on full combat power, as less that 7 days duration means it won't last a jump. If so, you should please tell us the equivalence to non-combat days.

You are right. Here is the note on the UCP sheet that gives all of the endurance figures (it was too long to put in the short UCP in the post above):

Note 1 - Power and Fuel: The power plant on a Citadel-class Auxiliary can provide a fraction less than 92,893 Mw of electrical power when operating at full capacity. However, the plant rarely operates at full output. Rather, the plant is normally "dialed back" to provide only the power needed at the time, in order to conserve fuel. At the lowest possible power output setting, the plant provides 7,796 Mw, enough to power essential life support and controls. This setting is called "minimum essential" (ME) and is used while the vessel is in jumpspace or when loiterng on a fixed station. At the "normal maneuver" (NM) power setting the plant produces 19,143 Mw, enough to power the maneuver drives (partially, allowing 1G of thrust), some weaponry (the missile and sandcaster batteries), the fuel purification system, and all communications and sensor systems. At the "combat maneuver" (CM) power setting the plant produces 52,323 Mw, enough to power all of the above systems plus operate the maneuver drive at the full rated 3G acceleration (the vessel has an agility rating of 0 at both NM and CM power settings). Finally, at full power - or "combat weapons" (CW) power, the meson gun bay, fusion guns, and laser turrets are powered in addition to all of the other shipboard systems.
Fuel is allocated for each power setting's estimated burn rate as follows: ME (3.9 kl/h) - 30 days, NM (9.6 kl/h) - 22 days, CM (26.2 kl/h) - 8 hours, and CW (46.4 kl/h) - 4 hours, for a total power plant fuel tank capacity of 6,016 kl (this does not including fuel tankage for the jump drive although fuel can be internally transferred from one tank to the other). Operating continuously at the indacted power setting and assuming a full power plant fuel tank, the vessel can operate at ME power for 64.3 days, NM power for 26.2 days, CM power for 9.6 days, and full (CW) power for 5.4 days. If a full j-drive tank's fuel is cross-pumped to the Power Plant tank, endurance is extended greatly allowing operation at ME power for 349 days, NM power for 142 days, CM power for 52 days, or full (CW) power for 29.3 days.

Also, if you accept suggestions from this newbee, in MT designs I always preferred the fusion gun turret to the lasers, most so if you don't intend to engage long range protracted boardsides. A fusion gun uses the same power than 2 lasers, but gives you factor 5 battery at TL 14-15 (MT errata), so has the offensive/antimissile power of 6 BLasers or 12 PLasers and has a +2 to penetrate sandcasters.
The drawbacks of needing double volume per turret and price are offset by the need of half (for BLasers) or a quarter (PLasers) that many turrets, thus resulting in same (or even less if PLasers) volume and less power, weight and price (and so CP and crew) for the same battery power. The only true drawback that leaves is his limited range to planetary (50 KK), more than enought for defense or planetary bombardement/ground support.
This is not true if you intend to have batteries with more than 5 power, as is your design, but perhaps 15 level 5 fusion batteries whould give better fire support to the dirtside element than your 3 level 7 laser batteries ( I assume you used BLassers).
I hope you won't see me as too daring for this suggestions on what seems a good design.

I'll accept suggestions from anyone so thanks! You bring up a good point that I need to look at. I used beam lasers because they had a lower power requirement and because they doubled as missile defense. I have to check again but I don't think fusion guns can be used for defense. They would be good fire support weapons but I need to see what I can afford to fit for the increased power plant they'll require. Conserving the plant size was my reason for limiting to only three batteries of lasers.

 

[McPerth]

I'll accept suggestions from anyone so thanks! You bring up a good point that I need to look at. I used beam lasers because they had a lower power requirement and because they doubled as missile defense. I have to check again but I don't think fusion guns can be used for defense. They would be good fire support weapons but I need to see what I can afford to fit for the increased power plant they'll require. Conserving the plant size was my reason for limiting to only three batteries of lasers.

MT don't specifies if energy weapons can be used for missile defense, but on the combat tables and combat explanation it only says that beam batteries may be declareet as anti missile fire (RM page 92, left column second to last paragraf) and I think to recall that beams are lasers and energy weapons (I could not find the exact quote now), so I assumed any beam can be used for that purpose.
About PP requirements, a gusion gun needs 500 Mw, against 250 Mw for a laser, but as you need only one fusion gun for the same battery factor that 6-12 lasers (BLasers or Plasers respectively) as long as you want factor 5 batteries, this is not a problem (500 Mw per battery against 1500-3000 Mw per battery), so you save quite a lot power if you have 15 factor 5 fusion batteries to replace you 3 factor 7 BLaser ones (7500 Mw for fusion against 11250 Mw for your 3 batteries).
In anti missile role, those 15 batteries will be easier to penetrate than your 3 (+2 on DR), but they are quite difficult to overload if fired by more than 3 missile salvoes and, if only 3 or less, they'll have to penetrate 5 or more deffensive fires each salvo, which I think more than offsets this DM.
The only true dawback I see on this is that I assumed to replace your 15 laser turrets with 15 fusion turrets, and that uses 15 dton more (202.5 kl), but you can reduce your PP by 208 Kl and have enought combat power to keep them powered (thanks to the 3750 Mw you save), so I don't see a problem there.

 

[aramis]

Energy Weapons are not light-speed shots, and not beams, either.
Lasers are, and PA's almost are, light-speed, and definitely beams

If a laser is used, the range in LS is doubled for effective lag to target, and 0 Reaction time for target.
With a .9C PA, you're looking LSx2.111, and target knowledge time of LS x0.1 for reaction.
With a 0.1C Plasma or Fusion, you're looking at LSx11 round trip time, and LSx10 for reaction time.

Given the accelerations, and the 0.1LS ranges typical, and the typical missiles 6G rating, that's 0.3m for the PA; a sweep still hits.

A Plasma or fusion, however, can be off by 30m at that range (30,000 km).

PA should be allowed, but I'd suggest the radiation makes up for the higher miss rate with extra punch.

Energy weapons, tho', should have serious penalties, IMO. Say, half, round up, UCP factor or worse.

 

[Major B]

Hull section

Okay, since I’m finally learning how to make technology work for me, I can start posting some of the design’s notes. Just the hull section to start today because I’m looking back on the design to see about adding some fusion guns to the weapon mix.

I initially hoped to fit this into a relatively small hull, but my first attempt at a 3600-Td vessel filled up fast. By the end, I more than doubled my initial estimate, settling on a 7900-Td design. I’ll admit that I could have squeezed it all into a smaller hull, but the more I looked at the problems associated with not just carrying but employing and maintaining the readiness of the landing force, the more space I thought was needed. A smaller ship is possible but I think this design is optimal. You’ll see why as I continue.

Hull: First, for the hull itself I wanted a streamlined design so it could refuel from gas giants. An irregular structure was appealing because it was inexpensive and saved weight (I also could have saved some hangar space by carrying the craft on the exterior), but the irregular structure can’t be streamlined so no skimming and I dislike reliance on fuel shuttles.

I decided on a box configuration for the best cost savings since a box is, strangely enough, cheaper to streamline than a needle/wedge or cone (the base hull price modifier is 0.6 then the modifier for streamlining is 1.5 for a net modifier of 0.9). I did not try for any agility in this design as this was not intended as a ship-to-ship combatant. Also, in MT the extra power required for agility gets expensive fast. The other advantage of no agility is that you can armor the design as much as you want (or can afford). A very high armor value was tempting, but also expensive, so I reduced the armor level to 58 which still provides a +6 defensive modifier and kept the hull cost (and the control points and maintenance crew requirements) manageable.

 

[Gray Lensman]

looks like it worked to me

 

[BillDowns]

Looks nice, but could you convert it to High Guard when you are done, please?

After reading your lengthy explanations, though, i wonder if 90 days supply is perhaps too much. It sounds like 30 days would be more than sufficient.

As for the armor, I would suggest armored small craft that perform the same function plus some air assault. Of course, they should have VTOL capability, but still able to reach orbit as needed. Say, 2 or 3 crew each.

You stated these would be Line Marines, but IMTU, this size of assault would be more Fleet Marine, with Line Marine equivalents landing at least a brigade, more probably a division. But YMMV

 

[McPerth]

Energy Weapons are not light-speed shots, and not beams, either.
Lasers are, and PA's almost are, light-speed, and definitely beams

If a laser is used, the range in LS is doubled for effective lag to target, and 0 Reaction time for target.
With a .9C PA, you're looking LSx2.111, and target knowledge time of LS x0.1 for reaction.
With a 0.1C Plasma or Fusion, you're looking at LSx11 round trip time, and LSx10 for reaction time.

Given the accelerations, and the 0.1LS ranges typical, and the typical missiles 6G rating, that's 0.3m for the PA; a sweep still hits.

A Plasma or fusion, however, can be off by 30m at that range (30,000 km).

PA should be allowed, but I'd suggest the radiation makes up for the higher miss rate with extra punch.

Energy weapons, tho', should have serious penalties, IMO. Say, half, round up, UCP factor or worse.

MT don't specify what are beam weapons, but I understand that energy weapons use the beam tables, so, if they are as accurate as beams, they should be able to be used against missiles too.
This speed difference you say is not as important, for I assume missiles are fired upon at quite near (in space distances) range (after all, sandcasters are used as anti missile fire and according to Players Manual have a maximum range of very long [500 m]), for they are too small to be fired upon at long range.
And last (but not least), through MT don't specifies it, HG (MT ship combat system is nearly a hard copy of it) specifies that beams usable against missiles are lasers and energy weapons (HG page 45 under MISSILE ATTACK TABLE: If a hit is achieved, then sandcasters, beam weapons (lasers and energy, each type uses the beam section), repulsors and dampers must be penetrated..., and under BEAM WEAPON TABLE: Beam weapons include lasers and energy (fusion and plasma) guns.
So I think energy weapons are beam weapons and can be used as missile deffense in MT too.

 

[aramis]

HG_B: I can see your point; Bk5 is more explicit than MT, and confirms your interpretation.

I think it's a bad call, but it's what's there.

As for sand... Sand's already in place before the missile gets there, rather than fired for intercept. You put the sand out once it hits the point of no fly-around, not as an active intercept. At least if Bk2 and Mayday are any indication (including the HG adaptations in Mayday).

 

[aramis]

Looks nice, but could you convert it to High Guard when you are done, please?

No need to convert, per se... just use the USP ratings as is.

The tonnages will be wonky (MT jump fuel tonnage is much lower past J1, and PP fuel not too much higher), but the overall ratings don't need any change, as they are EXACTLY the same.

 

[Major B]

McPerth, I've been looking at your suggestion. Even if the FG turrets can't be used for missile defense, their utility for providing support to the troops on the surface is very good.

I'm reluctant to remove any of the BLaser batteries though because I want their defense. Instead, I've replaced one of the missile batteries with single fusion gun turrets.

The net effects on the overall design are:
- reduce missile batteries from six to five
- gain six factor-5 FG batteries
- tonnage devoted to weaponry remains the same (each missile turret was one ton plus an extra ton adjacent for a missile magazine holding 45 battery-rounds)
- gunnery crew decreases from 30 to 29 reducing overall crew from 150 to 149 (and saving 4 tons for a small stateroom)
- power plant is increased in size slightly
- cargo reduced from 925 to just over 918 tons

Overall I think it a worthwhile modification. Thanks for posting the suggestion.

I'll be editing some of the above posts later today to reflect this change and posting more on the design discussion if I can get to it.

 

[Major B]

After reading your lengthy explanations, though, i wonder if 90 days supply is perhaps too much. It sounds like 30 days would be more than sufficient.

Bill, I think 30 days supply would be enough for most engagements but runs the risk of either putting the marines at undue risk and possibly harming Imperial prestige if they ran into a situation requiring a longer stay. My Fleet Marines carry 30 days because they are tied to the warships and the warships need to keep moving. The Line Marines handle the longer duration missions and anything over 90 days will require some form of commitment from the Army which has more support units and staff. Where I'm sort of stuck is figuring out how many tons of cargo space are needed for 90 days worth of supply. Got any guesstimates?

As for the armor, I would suggest armored small craft that perform the same function plus some air assault. Of course, they should have VTOL capability, but still able to reach orbit as needed. Say, 2 or 3 crew each.

That's what the shuttles do, and with eight of them on board the commander can lift two of his companies at a time and if he needs to can probably pack the third company into the Titans though that wouldn't be such a fun ride.

You stated these would be Line Marines, but IMTU, this size of assault would be more Fleet Marine, with Line Marine equivalents landing at least a brigade, more probably a division. But YMMV

I think my mileage is the same as yours . This is just one battalion from that brigade or group-sized unit. The line infantry battalions are a little bigger and not drop-trained so they are on another ship that can land them after the assault battalion clears the LZs. And the lift infantry / cavalry battalions are riding different ships too.

 

[Gray Lensman]

As far as food space goes...

Maybe someone will recognize this and can post the link to it, (I can't find Mine anymore ).

From: Ted7@qrc.com (Mitchell K Schwartz)
Subject: Food in Space
Date: Wed, 14 Sep 1994 16:32:22 -0400 (EDT)
Question about food aboard starships:
How much space aboard a vessel do rations take up?

I have the whole article but don't know about the legality of reposting it here.

Ammunition/fuel/spare parts shouldn't be to hard to figure.

 

[navanod]

My research indicates an MRE takes up about 120 cubic inches, or .001982 cubic meters, or 7000 per dton (3 meals per day, about 2333 man-days). This comes pretty close to the numbers given in GT: Interstellar Wars (1 dton, 2000 man-days, 12 tons weight). That's the only place I recall seeing it mentioned off the top of my head.

So, 1 dton of cargo will supply your troops for 4 days and change, or 7 dtons per month. That's just food, though, so I'd probably double that to account for medical supplies, toilet paper, replacement parts, etc. So 7x2x3= about 42 dtons for 90 days.

EDIT: Ah, GT: Starships uses the same number, but also notes you can carry 1000 man-days of fresh food instead of 2000 man-days of preserved.

 

[Major B]

My research indicates an MRE takes up about 120 cubic inches, or .001982 cubic meters, or 7000 per dton (3 meals per day, about 2333 man-days).

I'm praying now that future service members are spared from having to consume Meals Ready to Excrete.

Thanks for the numbers Navanod. I'm off to do some math and see where that leads.

 

[Major B]

Power Section

I should be able to finish updating the UCP and design sheets for the new version with fusion guns and posting them in the file library tonight. Then I'll be looking at the cargo allocation to see if I was excessive.

Here are my notes on the power section:

Power: As we go through the rest of the design sections, each item that requires power will have a note showing which of the four power categories it falls into. This does not mean I have multiple power plants. The categories allow me to plan out the fuel load for economy – rather than carry enough fuel to run at full power for 30 days I carry enough to run at minimum essential (ME) power for 30 days, normal maneuver (NM) power for around three weeks, combat maneuver (CM) power for as many hours as I think needed, and combat weapons (CW – full power) for as many hours as I think the design is likely to be in combat. The benefit to doing this is it allows you to keep the fuel tank's volume down to a reasonable figure.

For the Citadel, the fuel load required to run at full power for 30 days would take up 42,786.829 kl.

Using the above method, 30 days of ME + 22 days of NM + 8 hours of CM + 48 hours of CW gives a total tank size of 7,521.4 kl.

All this does is give you the size of the tank, it does not limit how long the vessel can operate at any given power setting. With a full tank, the Citadel can operate at ME power for 80 days. If operated continuously at NM power, a full tank will last 33 days. Operating at CM power will run the tanks dry in 12 days and full power will do the same in 5.27 days.

Also, keep in mind that the fuel in the jump drive tanks can be cross-leveled into the power plant tanks. If the J-Drive fuel is counted too, a Citadel can operate much longer without refueling but the vessel is at risk whenever it does not carry enough fuel to jump to safety plus enough to be able to reach a fuel source in the system it runs to.

EDIT: I've updated the inline image to show the figures for version 2.00, with cargo reduced and expanded weaponry and fuel stores. I've also updated the above endurance figures to match those of the newer design. Updates are marked in red.