MGT Only: Planetary invasion ships

[McPerth]

In the Warships in a small ship universe thread it was discussed about the dificulties for planetary landings and invasions.

Here I'll give some ships specially designed for such a mission, using the constrains given by Brandon C in his Capital ship design in a small ship setting (though using Core computers for large ships, for the reasons I gave there), as I understand it was at least partially what sparked the discussions.

See that those ships are not designed to act independently, as they are specialized for the troops' transport and landings (and some support), but need the rest of the fleet to achieve orbital superiority and to deffend them, as well as other transports for the supplies, etc...

 

[McPerth]

Troop transport

Troop transport ship:

Item	Notes	Tons	MCr
5000 dton hull	Hull:100 Structure:100	5000	500
Config	Closed Structure (partially streamlined, 70% batteries bearing)	-	-50
Jump Drive	Jump=3	200	400
Maneuver Drive	Trust=3	75	37.5
Power plant (TL 15 fusión)	Power=3	93.75	468.75
Jump Fuel	1 jump 3	1500	-
Power Plant Fuel	4 weeks	125	-
Bridge	-	25	2.5
Computer	Core 5 (rating 60)	-	30
Electronics	Base Military (0)	2	1
Weapons	20 double beam laser turrets (14 bearing)	20	50
-	20 double sandcaster turrets (14 bearing)	20	20
Crew accomodations	31 staterooms	124	15.5
Barracks	1300 marines	2600	130
Low Berths	10	10	1
Extras	Brieffing room	4	0.5
-	Ship's locker	-	-
Software	Maneuver (rating 0)	-	-
-	Fire Control/5 (rating 25)	-	10
-	Evade/3 (rating 25)	-	3
-	Library (rating 0)	-	-
Cargo	-	201.25	-
Totals	-	0	1447.775

This transport is for up to 1300 men (2 battalions)

Crew for the ship is 8 command, 4 engineers, 25 gunners and 15 service. All of them in double staterooms but the command personnel. Weaponry is mostly defensive, not being expected to fight. Price includes the 10% discount for mass builds (without it, cost is MCr 1619.75)

 

[McPerth]

Command and support ship

Command and support ship:

Item	Notes	Tons	MCr
5000 dton hull	Hull:100 Structure:100	5000	500
Config	Closed Structure (partially streamlined, 70% batteries bearing)	-	-50
Jump Drive	Jump=3	200	400
Maneuver Drive	Trust=3	75	37.5
Power plant (TL 15 fusión)	Power=3	93.75	468.75
Jump Fuel	1 jump 3	1500	-
Power Plant Fuel	4 weeks	125	-
Bridge	-	25	2.5
Computer	Core 5 (rating 60)	-	30
Electronics	Base Military (0)	2	1
Weapons	20 double beam laser turrets (14 bearing)	20	50
-	20 double sandcaster turrets (14 bearing)	20	20
Crew accomodations	80 staterooms	320	40
Low Berths	10	10	1
Extras	3 x Brieffing room	12	1.5
-	Ship's locker	-	-
-	5 x landers	2000	858.312
-	30 x 10 ton interface fighters	300	625
-	2 x 10 dton fighter's hangers	26	5.2
Software	Maneuver (rating 0)	-	-
-	Fire Control/5 (rating 25)	-	10
-	Evade/3 (rating 25)	-	3
-	Library (rating 0)	-	-
Cargo	-	271.25	-
Totals	-	0	2851.717

Price includes the landers and fighters. This ship is the carrier for the landers that serve as interface transport for the troops and the fighters that will give them air support.

Crew is 8 command, 4 engineering, 25 gunnery, 91 flight (includes the landers crew) and 15 service, all of them but command in double staterooms. There are 3 extra staterooms for high command staff if present to coordinate the invasión.

 

[McPerth]

Lander

Combat lander

Item	Notes	Tons	MCr
400 dton hull	Hull:8 Structure:8	400	16
Streamlined	-	-	1.6
Armor	Bonded Superdense: 15 points	50	20
Aerofins	-	20	2
Maneuver drive M	Maneuver=6	21	48
Power Plant M	Power=6	37	96
Power Plant Fuel	1 week	12	-
Bridge	-	20	2
Computer	Model 5 (rating 25)	-	10
Electronics	Basic Military (0)	2	1
Weaponry	4 triple beam laser turrets	4	10
Software	Maneuver (0)	-	-
-	Evade/3 (25)	-	3
Cargo	-	223	0
Totals	-	0	171.662

This is the main interface Lander for troops and supplies. It would represent the equivalent to the WWII LST. Heavily armored, fast and agile, its intended mission is to land the troops or supplies as fast as posible, using its lasers only on self-defense (though some opportunity targets may be shoot too, and is not rare to use them to give limited support to landed troops).

Troops have no dedicated accomodations for them, just packing in the hold until released (as, with 6 G trust and aerofins, the trip is expected to be relatively short runs). In a little cramped way, 2-3 troopers can fit in a ton, allowing the Lander to carry about 450- 670 men (a full battalion) per trip¹, so allowing a strong landing to profit from the initial concentration advantage over the defenders. Vehicles can also be landed that way (depending on their tonnage and heigh, as the cargo floor is only 3 m high).

EDIT: the Lander has two large lateral clamp doors to allow quick release of the troops/vehilces once landed END EDIT

Once the beachhead (spacehead? skyhead?) is achieved, the same landers are used for supplies and reinforcements, as well as evacuation of needed troopers.

Grav belt equiped troops (or grav vehicles) can also be released from variable heights at need if the plan is more like a pradrop assault or if the Lander is damaged.

Crew is pilot and 4 gunners. Both accomodations for the crew and engineers to serve the Lander are in the tender.

Note 1: while MgT:HG rules talk about 1.5 ton per passenger as cabin space, in troop transports less space is required (as in the ATV in CB page 103, where a 10 dton vehicle can have 15 passengers). So, and basing my calculations in 2 squares per dton, I allowed 2-3 troopers per dton. I guess the vehicles book will have more details, but I don't have it​

 

[McPerth]

Interface fighter

Interface fighter:

Item	Notes	Tons	MCr
10 dton hull	Hull:0 Structure:1	10	1
Streamlined	-	-	.1
Armor	Bonded Superdense 15 points	1.25	1.25
Aerofins	-	0.5	0.05
Gravitic Drive sE	Trust=10	2.5	4
Fision Power Plant sG	Power=12	3	6
Power Plant Fuel	12 hours	0.075	-
Crew Cockpit	1 Crewmember	1.5	0.05
Computer	Model 3 (rating 15)	-	2
Electronics	Standard (-4)	-	-
Weapons	Single Pulse Laser	1	0.7
Software	Maneuver (0)	-	-
-	Fire control/3 (rating 15)	-	8
Totals	-	0.175	20.835

This is the atmospheric variant of the 10 dton fighter. it has reduced trust to fit the aerofins for atmospheric maneuvering. Weapon has also been changed to laser because the PB cannot be used from space to atmospheric targets or vice-versa.

Its main role in planetary invasions is to achieve air superiority over the landing zone and to act as close air support for the troops.

 

[Brandon C]

How do you transfer troops from the troop ship to the landers? Perhaps the cargo space on the troop ship is used for small craft to shuttle the troops?

HG errata includes small craft acceleration couches at 0.5 tons, which may be what you are looking for. I assume the landers are preloaded with the vehicles of the troops and at least some supplies for a few days.

 

[McPerth]

How do you transfer troops from the troop ship to the landers? Perhaps the cargo space on the troop ship is used for small craft to shuttle the troops?

Just docking one another. As those are no moving opperations, no docking clamps are needed (or so I understand), as they are for extended opperations.

HG errata includes small craft acceleration couches at 0.5 tons, which may be what you are looking for.

Yes, I guess that's what I looked for, but in such a ship, not even such couches would be likely (after all, in the LST most troops were not even seated, so that more could be fited in one of them)

I assume the landers are preloaded with the vehicles of the troops and at least some supplies for a few days.

The landers are preloaded (as said by docking on the transport ships) and troops/vehicles are loaded on them. Supplies for the first hours are scarce, as I expect most those troops to be as supply-light as posible (energy weapons, mostly lasers to avoid need for amunition, etc...), but off course some of them must be loaded in the first or second wave...

 

[wbyrd]

I'd use them

Nicely thought out. First suggestions I have...

add radiation shielding to EVERYTHING..for at least some protection from nuke/PB generated rad hits.hardened computers and bridges would be a good idea too....no sense making it easy to knock down your craft with EMP and rads.

At least some ballistic weaponry for the ships. Missiles or Railguns that can be loaded with ortillery rounds. lasers are perfectly fine no reason not to use them. However, few ortilery rounds sure wouldn't hurt.

Add heat shielding to the Interface craft both lander and fighters. That would give them the ability to make a hypersonic dive into the atmosphere.

Internal bulkheads for the cargo areas and bridge of the troop carriers and landing ships. Just in case something gets through the armor, it protects the squishy bits in the hold.

adapt some of the fighters as bombers. Use missiles for ground support. After all, while the rules aren't supportive of this fact, a missile can hit over the horizon, and around terrain. So switch the lasers, to missiles, and load ortillery...

you might even be able to tweak the design to allow a railgun barbette. That's going to punch through anything on the ground, or in the air.

Maybe it's me but I just like the idea of having artillery support

hmm final thought on that subject...sine you can mount vehicle weapons on small craft...maybe one designed specifically for fire support, either MRLS, or conventional artillery mounted to turn it into a mobile gun platform.

Even if it only has thrust 3. It's going to handle like a pig next to a fighter... it's gong to be one agile hog compared to tanks/gun carriers

Last Idea. basically a 10 ton troop carrier. just armor and cargo space.

Can you tell I have thought about this idea a LOT.

 

[Brandon C]

At least some ballistic weaponry for the ships. Missiles or Railguns that can be loaded with ortillery rounds. lasers are perfectly fine no reason not to use them. However, few ortilery rounds sure wouldn't hurt.

I was working out the TO&E of the troops and realized that, for an assault force, they really don't need an artillery component, as this can be handled by the naval craft, either larger ships bombarding from orbit or small craft making closer runs.

adapt some of the fighters as bombers. Use missiles for ground support. After all, while the rules aren't supportive of this fact, a missile can hit over the horizon, and around terrain. So switch the lasers, to missiles, and load ortillery...

The rules for artillery combat in Supplement 4: Central Supply Catalogue may be useful here.

you might even be able to tweak the design to allow a railgun barbette. That's going to punch through anything on the ground, or in the air.

And the relatively short range of railguns is less of a disadvantage in such cases.

 

[flykiller]

is there any reason for a troop transport to be j3? (using the spinward marches as a guide) there are very few systems which cannot be reached by j2.

 

[Condottiere]

In theatre mobility.

It would be a shame that if by the time they get there, it's all over.

 

[flykiller]

dunno man, hard to envision an invasion taking place in a fluid strategic situation.

 

[McPerth]

I'd use them

Nicely thought out. First suggestions I have...

First of all, glad you like it.

Many good points. Most of them already considered, and, maybe due to a matter of doctrine, discarded

add radiation shielding to EVERYTHING..for at least some protection from nuke/PB generated rad hits.hardened computers and bridges would be a good idea too....no sense making it easy to knock down your craft with EMP and rads.

As for the landers and fighters, armor 15 (in fact 8+, as explicited in HG page 79, and not so explicity but clear in CB page 151 radiation damage table) makes you imprevious to radiation damage (mesons excepted, off course).

As for the Troop transport and command ship, they are not intended to go close enough of the enemy to need it (see that their weapons are purely defensive), and it would cost 1250 MCr/ship...

At least some ballistic weaponry for the ships. Missiles or Railguns that can be loaded with ortillery rounds. lasers are perfectly fine no reason not to use them. However, few ortilery rounds sure wouldn't hurt.

adapt some of the fighters as bombers. Use missiles for ground support. After all, while the rules aren't supportive of this fact, a missile can hit over the horizon, and around terrain. So switch the lasers, to missiles, and load ortillery...

you might even be able to tweak the design to allow a railgun barbette. That's going to punch through anything on the ground, or in the air.

Maybe it's me but I just like the idea of having artillery support

Not that I underestimate artillery, but such an opperation will already be a logistical nightmare without the need to add missiles and oritllery ammunition to the equation. That's why I told about supply light troops using energy weapons, that only need power as ammo (a single ship with a functioning PP landed can provide power for many weapons' recharges).

And in any case, remember that a whole fleet is expected to be supporting the opperation, first achieving orbital supremacy, then suporting the landings and protecting the opperation...

Add heat shielding to the Interface craft both lander and fighters. That would give them the ability to make a hypersonic dive into the atmosphere.

As I understand heat shielding (HG, page 41) is intended for non gravitic ships/crafts (as explicited in its explanation, when it says A ship wihtout a functioning gravitic drive). As this is not the case, I didn't see the need for them (that would add Mcr 40 to each Lander and MCr 1 to each fighter)

Internal bulkheads for the cargo areas and bridge of the troop carriers and landing ships. Just in case something gets through the armor, it protects the squishy bits in the hold.

Bulkeheads need space, and you don't have to spare...

hmm final thought on that subject...sine you can mount vehicle weapons on small craft...maybe one designed specifically for fire support, either MRLS, or conventional artillery mounted to turn it into a mobile gun platform.

Even if it only has thrust 3. It's going to handle like a pig next to a fighter... it's gong to be one agile hog compared to tanks/gun carriers

I've thought several times about adding a VRF GG or similar to the fighter, but I guess that needs the vehicles book, that, as I already said, I don't own...

Last Idea. basically a 10 ton troop carrier. just armor and cargo space.

Inefficient compared with the larger ones. in a 10 dton craft, (as you can see with the fighter) just armor, PP drives and cockpit will take you about half the space, only allowing you to carry, at most 10 troopers (at 2/ton). So, in 400 dton of such carriers, you could only carry about 400 troopers (at 2/ton), while in the landers you carry nearly 450 (at the same rate), and you need less crewmemebers in your command/support ship.

Can you tell I have thought about this idea a LOT.

I see it...

 

[McPerth]

is there any reason for a troop transport to be j3? (using the spinward marches as a guide) there are very few systems which cannot be reached by j2.

Mainly because that's the standard jump Brandon C (that, as said I used as reference for the setting) uses in his fleet. If the troops cannot go with the fleet, you need more ships dedicated to escort them.

Off course, if designed for J2, more troops and supplies can be carried...

In theatre mobility.

It would be a shame that if by the time they get there, it's all over.

In fact, such an invasion is likely to take time enogh as for this not to be a problem, and it will not start before orbital supremacy has been achieved, so usually some time dedicated to mopping up the system...

 

[whartung]

Really kind of hard to design ships like these without some idea of what kind of environment they're entering.

Is there anything that documents and describes rules for interface combat? Or is it all extrapolated from things like Striker and FF&S? Pretty sure both have rules on things like laser attenuation with atmosphere.

I would think the damage profiles of ships would be different from vacuum environment and an atmospheric one. A hull breach is not as big a deal in space vs the reduction of streamlining integrity within the atmosphere. Also the effect of nuclear weapons is far different in and out of atmosphere (assuming someone is willing to use them in atmosphere).

if the planet is effectively subdued, then you can just use freighters, or specially designed troop ships.

I don't think a "hot" landing would come from space, rather it would land nearby and come over land. Why expose the vehicles from orbit if you can insert farther away and fly NOE, leveraging terrain?

It's also a matter of doctrine as to how hardened the planets are themselves with fixed defenses (deep meson site, anti-vehicle laser batteries, missile batteries) versus relying on a mobile in space forces.

 

[Brandon C]

Mainly because that's the standard jump Brandon C (that, as said I used as reference for the setting) uses in his fleet. If the tropos cannot go with the fleet, you need more ships dedicated to escort them.

To be honest, I picked J3 as a generic number. FWIW, the capital ships in HG are J3 or J4 (excluding the planetoid monitor), so it may be a reasonable compromise.

 

[McPerth]

Really kind of hard to design ships like these without some idea of what kind of environment they're entering.

Sure, but unfortunately you must design them before knowing where will they be used, as if you wait until you have chosen the target, you'll have to wait some months (at least) until they are ready...

Off course, if you have to invade a vacuum planet, the streamlining and aerofins are wasted ressources, but it will serve too.

Is there anything that documents and describes rules for interface combat? Or is it all extrapolated from things like Striker and FF&S? Pretty sure both have rules on things like laser attenuation with atmosphere.

I would think the damage profiles of ships would be different from vacuum environment and an atmospheric one. A hull breach is not as big a deal in space vs the reduction of streamlining integrity within the atmosphere. Also the effect of nuclear weapons is far different in and out of atmosphere (assuming someone is willing to use them in atmosphere).

There are no specific rules that I know about, so it's mostly extrapolated from other rules. And no nukes are expected to be used when defending a planet against a fleet that can obliterate your civilization and render your planet barren (after all, they already have orbital supremacy if the invasión has begun).

My assumption is that if the planet is going to be invaded, just nuking it is not an option (usually for political reasons). The defender knows it, and also knows that those political reasons may be void if they are the first to use the nukes.

if the planet is effectively subdued, then you can just use freighters, or specially designed troop ships.

If the planet is subdued it will surrund without an invasion needed.

I don't think a "hot" landing would come from space, rather it would land nearby and come over land. Why expose the vehicles from orbit if you can insert farther away and fly NOE, leveraging terrain?

Neither do I think they will fall over the enemy troops à la Crete or Arnheim if they can avoid it, but the landing ships must be protected, as many weapons capable to damage them can do it from quite a long distance (and they don't know what kind of surprises they can find).

And remember those ships expect to return to orbit for the second wave and/or supplies when the combat zone is already commited, and the defender is not likely to just watch at the landings...

It's also a matter of doctrine as to how hardened the planets are themselves with fixed defenses (deep meson site, anti-vehicle laser batteries, missile batteries) versus relying on a mobile in space forces.

I'd say more a matter of setting than doctrine, but I agree with your reasoning here. In any case, if we are talking about planetary invasions, planets must be assumed to be defended (otherwise you don't need to invade them), but either softened by the fleet or not too much so if they can be invaded...

 

[wbyrd]

First of all, glad you like it.

Many good points. Most of them already considered, and, maybe due to a matter of doctrine, discarded

Okay fair enough. I can see your reasoning on the points I brought up.

the only one I cant wrap my head around is the lack of ballistic/indirect fire capable weaponry on support ships/landers.

Even with global space/orbital superiority. Local superiority can't be assured. If one of those nasty meson guns, or even specially built small craft, with heavy ship grade weapons is in an area exposing your fleet to potentially dangerous ground fire is risky...

the fleet is not going to willingly put their multi-Mcr assets at te wrong end of a shooting gallery. For example the navy refused to allow destroyers to close in and give direct fire support to ground force on Normandy, until a destroyer commander basically begged for permission several times.

on Guadalcanal a sudden counter attack forced the navy to pull it's ships away from ground support duties to engage the enemy force

even A 20 ton small craft armed with rail guns is going to pose a problem to a ship in low orbit. especially if they are in reinforced firing positions, or hiding in concealed pits. if unable to hit them from over the horizon starships would have to soak up a lot of damage to take down an anti-invasion site.

lord help the poor commander who wanders over a nest of concealed missiles, or the equivalent of a 50 ton fusion gun/railgun bay, hidden in a hillside. ( see guns of Cherburg, or Pointe du Hoc). Ground guns are a lot cheaper to build in numbers than starships.

Those sorts of guns can not repel a fleet, but they would force orbiting warships to come over the horizon and into their gun sights to neutralize them.

They can be taken out by ground forces...BUT,Any assault without integrated mobile ground, or small craft mounted indirect fire. Will have do so without artillery support.

same situation for ground forces without mortars and grenade launchers....

modern armies put up with the logistical nightmares having those in inventory cause for a reason. They need the flexibility and firepower they bring to the table.

Even a trooper armed with a Plasma rifle/gun,or a man portable fusion gun can't penetrate several meters of good old dirt. Every hillock becomes a choke point at that point. Rear slope defenders, with indirect fire weapons, can saturate any attacking force with fire. With absolutely no chance of return fire from line of sight only energy weapons.

You might have a completely different take on this...I just wanted to explain my thinking and why I am having a hard time with that one point. By the way when you can reduce a list like my original post down to one point..you did a fine job.

 

[Brandon C]

Populations can be very random ...

Looking at CT Adventues 2 and 7, the Rhylanor subsector has 131.1 billion people on 32 worlds (two with Pop 0), while the Vilis subsector has only 2.324 billion people on 26 worlds (three with Pop 0). Only one of these 58 worlds (Rhylanor) has the population (A) and tech level (F) to make it a true nightmare to invade.

For example, Aden is Pop 9 but only TL 8, making it a much lesser challenge to a TL 15 invasion force, and Vilis, same Pop but TL A, isn't going to be drastically harder. And tose are the two more heabily populated worlds in the Vilis subsector.

 

[McPerth]

the only one I cant wrap my head around is the lack of ballistic/indirect fire capable weaponry on support ships/landers.

Even with global space/orbital superiority. Local superiority can't be assured. If one of those nasty meson guns, or even specially built small craft, with heavy ship grade weapons is in an area exposing your fleet to potentially dangerous ground fire is risky...

the fleet is not going to willingly put their multi-Mcr assets at te wrong end of a shooting gallery. For example the navy refused to allow destroyers to close in and give direct fire support to ground force on Normandy, until a destroyer commander basically begged for permission several times.

on Guadalcanal a sudden counter attack forced the navy to pull it's ships away from ground support duties to engage the enemy force

even A 20 ton small craft armed with rail guns is going to pose a problem to a ship in low orbit. especially if they are in reinforced firing positions, or hiding in concealed pits. if unable to hit them from over the horizon starships would have to soak up a lot of damage to take down an anti-invasion site.

lord help the poor commander who wanders over a nest of concealed missiles, or the equivalent of a 50 ton fusion gun/railgun bay, hidden in a hillside. ( see guns of Cherburg, or Pointe du Hoc). Ground guns are a lot cheaper to build in numbers than starships.

Those sorts of guns can not repel a fleet, but they would force orbiting warships to come over the horizon and into their gun sights to neutralize them.

They can be taken out by ground forces...BUT,Any assault without integrated mobile ground, or small craft mounted indirect fire. Will have do so without artillery support.

same situation for ground forces without mortars and grenade launchers....

modern armies put up with the logistical nightmares having those in inventory cause for a reason. They need the flexibility and firepower they bring to the table.

Even a trooper armed with a Plasma rifle/gun,or a man portable fusion gun can't penetrate several meters of good old dirt. Every hillock becomes a choke point at that point. Rear slope defenders, with indirect fire weapons, can saturate any attacking force with fire. With absolutely no chance of return fire from line of sight only energy weapons.

You might have a completely different take on this...I just wanted to explain my thinking and why I am having a hard time with that one point. By the way when you can reduce a list like my original post down to one point..you did a fine job.

Well, that's exactly the role of the fighters. They are fast, agile, and armed with a Pulse laser for air superiority/close support. If the pilot has Gunnrey skill, they fire them (with a -1 to both, gunnery and pilot skill, as for multiple tasks) with a +3 FC modifier, if not, it can be fired by the FC program at +2, so overcoming the -2 modifiers Plasers have (and I forgot about weapons augments, but you can be sure they have the accurate one). And they deliver 100d6 damage in personnel/vehicle scale (remember that the conversión fator is 50). And this is aside form any vehicular weapon that could be added to them...

And, about mortars and light artillery, I expect the troops themselves having them in their TOE and vehicles, as they reach the combat zone...