CT Only: How big an infantry unit can fit into a 3,000dton hull?

[Golan2072]

I was thinking about troop transport in my Visions of Empire setting, which is a Book 1-3 Classic Traveller setting with a few add-ons from Book 4 (Mercenary). I was thinking how big an infantry unit (of ground troops) can you fit in a 3,000dton Assault Transport? A reinforced company? A Battalion? I was specifically thinking of a Grav-mobile infantry unit with full grav transport for all troops involved and their supplies.

How big a unit could fit into a 3,000dton ship? Into a 1,000dton ship?

Also, note that IMTU TL12+ low berths are quite safe (except for a slight "freezer burn" on revival), so some military units will simply be transported frozen.

 

[rancke]

I was thinking about troop transport in my Visions of Empire setting, which is a Book 1-3 Classic Traveller setting with a few add-ons from Book 4 (Mercenary). I was thinking how big an infantry unit (of ground troops) can you fit in a 3,000dton Assault Transport? A reinforced company? A Battalion? I was specifically thinking of a Grav-mobile infantry unit with full grav transport for all troops involved and their supplies.

How big a unit could fit into a 3,000dton ship? Into a 1,000dton ship?

Depends on the payload which depends on the jump capability. The Caen class dropship [GT: Ground Forces, p. 97-101] is a 1,200T J4 ship carrying a line Marine company and its 25 Astrin APCs. A full company has 309 officers and men.

Multiply that by 2.5 and you can get 2½ company, or roughly 750 men, into a 3,000T ship.

Note that GF introduces the bunkroom where room for 16 men takes up 4T. I wonder if this includes the additional life support equipment for the 14 extra bodies stuffed into the space that usually only holds two?

Be that as it may, if you only allow 2 men per 4T stateroom, you can only have eight times as many men, or roughly 40, in a 1,200T hull.


Hans

 

[Golan2072]

My initial thought is to differentiate Drop units (which are deployed from ships in orbit, carried 2 per 4dton stateroom) from Line units, which are carried in cryo-sleep (pretty much safe in this setting at TL12+ if properly maintained) and thus 8 per 4dton (with low berths being 0.5dton each). The Drop elements capture the beachhead and key installations, then the bigger ships land and unload full grav-mobile Line elements (whose troopers slept into cryo until the landing).

 

[Selandia]

I would say that it breaks into two exercises, Ib linked to II;

I) Space operation: Your assault transporft have to be part of a landing force and must fit the relevant operational enveloppe.

Furthermore, within AT there are specialized transport. Is it a 3000 t AT with Ro-Ro operation (a LandingStarshipTank)? Is it a jump troop carrier? How far can it relies on its own boat, does he need to?

a) How much of the X tons are available for troops once you get the J, G, Wpn, fuel, crew ....accounted for. That suppose that you decide if your landing force is carried on a tender or if ships are capable of independant jump.

b) how many assault boat you need , or said differently how many "waves"

II) nature of payload:

a) Figure the overall space needed per squad, taking into account all gear and supply expected to be needed before first replenishment is possible. That is your basic building block (your lego block), time the number of squad per platoon, add platoon HQ and you have your basic unit. Redo for Higher level HQ squad/platoon and various support platoon.

b) figure how that unit need to be deployed so to be a coherent fighting whole given that out of ship A B C D in your force you may loose ship B before it unload. The result is the load you should design for.

If tonnage is preset at 3000t with independant operation in ming, you just stuff as much as you could given the unit type.

Note that ship'boat may be pre-loaded with gear of with vehicule that are themselves loaded before being loaded and finaly boarded at the last minute.

have fun

Selandia

If the ship is for independent operation,

 

[Golan2072]

Note that this is CT LBBs 1-3 at TL13 (which I might push to 14 if necessary) - Jump-3 ships are 1,000dton at most, Jump-1 at 3,000dton at most. So the orbital assault transport will be around the size of a Kinunir, maybe a little smaller (and with lighter guns - it is not a main ship of the line, after all) while the combat lander will be either 1,000dton (fast Terran Guard low-berth transport) or 3,000dton (slow Terran Army transport).

 

[Golan2072]

I) Space operation: Your assault transporft have to be part of a landing force and must fit the relevant operational enveloppe.

Furthermore, within AT there are specialized transport. Is it a 3000 t AT with Ro-Ro operation (a LandingStarshipTank)? Is it a jump troop carrier? How far can it relies on its own boat, does he need to?

The big 3,000 dton slow transport lands in full and unloads its Terran Army passengers and equipment, then takes off to take another round of troop transport (after frontier refueling in many cases or refueling by a tanker). The 1,000 dton assault transport wakes its Terran Guard passengers from low-berth in orbit, then loads them into their Grav-Gunships (i.e. G-Carriers) which are capable of atmospheric entry; it then provides some orbital fire support for its troops. The 1,000 dton Drop Carrier is similar but launches most of its troops by drop-capsule then sends their Grav-Gunships after them for support and also stays in orbit to provide fire support.

a) How much of the X tons are available for troops once you get the J, G, Wpn, fuel, crew ....accounted for. That suppose that you decide if your landing force is carried on a tender or if ships are capable of independant jump.

They are independent jump ships... Let's see: 1,000dton custom hull, M-Drive H, P-Plant Q, J-Drive Q, total 141 dton Engineering, Fuel is 300 dtons for 1-Jump-3 and 2-G acceleration, 10 triple turrets require 10 dtons for fire control, 20 dtons bridge, crew is at baseline 1 pilot, 1 navigator, 4 engineers, 2 medics, 10 gunners total 18. Pilot (captain) and navigator (XO) get single staterooms, the others get double occupancy so 40dtons staterooms, let's say 9 dtons magazine for ortillery missiles. So 480 dtons payload. For the 3,000 dton ship that's 3,000 dton custom hull, M-Drive Q, P-Plant Q, J-Drive Q, total 155 dton Engineering, Fuel is 600 dtons for 2-Jump-1 and 1-G acceleration, 10 triple turrets require 10 dtons for fire control, 60 dtons bridge, crew is at baseline 1 pilot, 1 navigator, 5 engineers, 3 medics, 10 gunners total 20. Pilot (captain) and navigator (XO) get single staterooms, the others get double occupancy so 44 dtons staterooms. So 2,131 dtons payload.

b) how many assault boat you need , or said differently how many "waves"

One "wave" of Grav-Gunships for the 1,000 dton ships, no need for "Waves" for the 3,000 dton slow transport (it lands and unloads).

 

[aramis]

I was thinking about troop transport in my Visions of Empire setting, which is a Book 1-3 Classic Traveller setting with a few add-ons from Book 4 (Mercenary). I was thinking how big an infantry unit (of ground troops) can you fit in a 3,000dton Assault Transport? A reinforced company? A Battalion? I was specifically thinking of a Grav-mobile infantry unit with full grav transport for all troops involved and their supplies.

How big a unit could fit into a 3,000dton ship? Into a 1,000dton ship?

Also, note that IMTU TL12+ low berths are quite safe (except for a slight "freezer burn" on revival), so some military units will simply be transported frozen.

How fast do I have to get them there?

 

[Golan2072]

The 1,000 dton ships is 1-Jump-3, 2-G, the 3,000 dton ship is 2-Jump-1, 1-G.

 

[samuelvss]

I was thinking about troop transport in my Visions of Empire setting, which is a Book 1-3 Classic Traveller setting with a few add-ons from Book 4 (Mercenary). I was thinking how big an infantry unit (of ground troops) can you fit in a 3,000dton Assault Transport? A reinforced company? A Battalion? I was specifically thinking of a Grav-mobile infantry unit with full grav transport for all troops involved and their supplies.

How big a unit could fit into a 3,000dton ship? Into a 1,000dton ship?

Also, note that IMTU TL12+ low berths are quite safe (except for a slight "freezer burn" on revival), so some military units will simply be transported frozen.

Changing low berths changes everything, however, I am just addressing troops in staterooms.

The number who can fit in the ship depends on the role of the transport. "Assault Transport" can mean that it is intended as forced entry, potentially against naval assets; that would radically change my answer, depending on how much of this bad boy is fighting ship, and how much in transport.

Obviously, the jump number is relevant. First, I assume J3. Less makes it pretty useless as a transport by slashing operational mobility. Then, I would assume 3-4 dtons per troop, mechanized, regardless: two troops per small stateroom, plus vehicles, supplies, and a lesser tonnage of boats or drop tubes.

Another assumption: this is not a fighting ship, but rather a ship making its landing of troops against a potentially opposed landing. It is thus armored, and defended, but does not sport much offensive weaponry. Escorts would be added, as needed to address the threat.

Here's AN example that I whipped up on HGS:

Shining Spear, 3,000 dton Gleaming Gimlet class Assault Transport

USP TA-C321344-350100-00000-0 MCr 2,049.42 3 KTons
Bat.Bear. A Crew 383 TL12 (That's 10 factor-5 sandcaster batteries, all of which bear).

Cargo: 151.000 Passengers: 4 Fuel: 990.000 EP: 90.000 Agility: 1 Marines: 300
Craft:, 2 x 50T Cutters, 4 x 30T Cutter Modules
Fuel Treatment: Fuel Scoops and On Board Fuel Purification
Architects Fee: MCr 20.614 Cost in Quantity: MCr 1,649.138

Note that the 3 dtons per troop includes the open space on cutter modules.

Drop the armor (factor 3), gain another 80 troops. Make it J2, gain another 100+.

Makes your troops light infantry, J2, and drop the armor you could go down to just an extra .25 dton per troop, and carry another 400. Increase the armor, or jump, and you've got no space for troops.

 

[aramis]

The 1,000 dton ships is 1-Jump-3, 2-G, the 3,000 dton ship is 2-Jump-1, 1-G.

KK...

So...
Assuming double occupancy all around as it's military crew, and streamlined ship as lander to reduce small craft need (1 launch for utility purposes).

J3, 3G P3. Launch. 10 Trip Turrets each with Missile, BLaser, and Sand. 24 ship's crew.

Pure leg: 12 man squads with 1Td supplies per squad.
14 squads (as double occupancy in standard SR), plus 20Td of supplies. A heavy company (4 platoons of 3 sq, plus 2 sq HQ section). (That's 6 extra Td supplies.)

Grav Infantry: 14 man squads in G-Carriers. (12 men, plus 2 crew, + g-carrier) 10 squads. Light company (3 platoons of 3 plus HQ squad). 8 Td extra supplies.

MBT Armor: 4 man plus 10Td tank per squad. 20 squads. 2 companies of 10 squads each (3 Plt of 2 sq, + 1HQ Sq). 8 extra Td supplies.

LBT Armor: 3 man crew + 6 Td tank per squad. 30 squads, or an ad-hoc Battalion of 3 10-squad companies. 8 Td extra supplies.

 

[Quint]

This question is at part of the root around all of my various logistics questions over the past few months. Fundamentally you have to decide what your Empire's strategic vision and general operational plan is.

Bigger question than "how many troops on the ship?" is "how many troops are deployed?" along with "how long are they supposed to operate?"

Plus, are they leg infantry? grav-mobile? grav-assault? I have a huge spot in the TOE for leg infantry because they are so much easier to transport - and that is also why I was thinking of "grav-cav" (gravbikes or similar), much easier interstellar transport.

With the side question, is their initial equipment load for X weeks included on the ship, or sent on a separate ship that travels alongside?

IMTU (a relatively Small Ship universe), Army troops are generally deployed in Battalion-sized units, and some with what is supposed to be a three-month supply. COACC comes on a separate ship. Special Op missions (with all those drop troops) move fewer troops, faster - and the Marines are the real RDF (usually in a company, people worry when a Battalion of marines gets deployed).

Romantically this is because the battalion is historically the smallest "independent unit" able to operate on it's own without any support - that's kind of a fallacy in many ways, but is still true enough.

But the Army uses Troop Transports, not warships - they are basically armed merchant ships. They generally aren't doing hot drops from orbit, that's a job for the marines - the LZ may be hot, but handling serious resistance to insertion is a specialist job not that of the standard grunt.

D.

 

[aramis]

To explicate why I chose the numbers I did...

Leg Infantry - that 1Td per 10 men is (roughly) 1 cubic meter per man, plus 1 cubic meter of squad assets. That's, I figure, rations and ammo. If not needing life support, just food, then 1 cubic meter is 250-1000 person-meals (C-Rats+1L bottled water vs MRE relying upon local water). For a 12 man squad, 20 meals is (roughly) a week of combat or two of garrison. A basic load of ammo in clips is about 1L per clip, probably ship with 10 clips, and then 3L is 500-1000 rounds in a can. A light field tent is about 2L rolled, a more substantial one about 100L; you can use 1 cubic meter for a squad tent in canvas including a heating unit.

So, each man can be allotted several weeks rations, several firefights of ammo, and a pup tent, plus a squad getting a GP tent and some extra goodies.

For Mech Inf, the food is stowed on the G-carrier during transit, in lieu of the troops being aboard. Less efficient, but easily 21 cubic meters of space to stow stuff en route. If they need to drop hot, they move much of it to bunks before hitting atmo.

Armor is likely to have 2 weeks rations stowed aboard grav-armor... it's got long term LS. Plus, packed aboard, you can stack a couple cubic meters beside the gun during transit. Again, hot drop, pull it before entering.

Light tanks are one of the ones from MT - in 101 vehicles.
MBTs are also a 10Td one from MT. I didn't do trepidas - they're actually 14Td, 3 crew,

HBT's would be 15Td, like the Trepida or the Zhodani equivalent.

Oh, and I forgot - per the MT articles on BD, BD troops need about 1/2Td per man for suiting rack, plus the squad would need a ton, too, just like leg, so a 12 man squad would be 7Td cargo.
I get the same basic hull replaced with 11 squads of BD and 27 extra tons of cargo for BD. A light company (3 Plt of 3 Sq + HQ sct), and that's enough to add a modular base and several air/rafts and/or speeders.

And Grav Scouts.
In speeders: 2 men per speeder (1 crew, 1 mechanic), 6 tons for the speeder, 2 speeders per element (squad), plus 1 Td/squad for spares and food. Call it 13 Td+4SR per squad. I can fit 17 such squads - a heavy squadron - 4 flights of 4 elements each, plus a command element, and 11 extra tons.

On Grav Bikes, 1 per man - 1Td/man, plus an air/raft for supplies and 2 mechs (guys are expected to take on more mechanical tasks) per 4 man element. So each element is 6 guys, 8Td. 18 such elements, for a heavy squadron of 4 flights of 4 elements plus 2 HQ elements. (One of which is probably actually a G-Carrier with a TOC/BDC/EW role). And 8 extra tons of gear. Quite likely to be a portable shop. That's a HUGE lot of birds - 68-72 grav bikes, 17-18 air rafts, 0-1 G-Carrier-MTOC/TDC/EW.

 

[Golan2072]

Many thanks for these numbers!

 

[Golan2072]

This question is at part of the root around all of my various logistics questions over the past few months. Fundamentally you have to decide what your Empire's strategic vision and general operational plan is.

The United Terran Republic (UTR) uses attrition warfare when on the defensive and maneuver warfare when on the offensive. That is, each UTR world is defended by large local forces equipped with locally-produced tech (typically lower than the nominal TL13) organized for prolonged ground combat (and orbital defense) and if neccessary (under enemy occupation) a protracted guerrilla war or harassment. Attacks on enmy worlds, on the other hand, are based on much smaller, but far more trained and equipped, forces - Terran Guard (elite) followed by selected Colonial army units (riding slower ships).

The UTR in this setting was very recently fighting a superior force - the Reticulan Empire; however the UTR's small size in comparison to its rival actually played to its advantage, as supply and communication lines are much shorter. Due to its size, enemy attacks on many UTR worlds are expected - there is little or no "buffer"; a major part of the war involved dragging the Reticulans to prolonged planetary-surface fighting tying many of their forces in local combat while fast UTR elite forces try to flank them and execute lighting attacks on key Reticulan worlds. This eventually worked leading to a decisive, though highly costly, Terran victory. (the Terrans also managed to incite rebellion among the many subjects and vassals of the Reticulans, which also helped secure this victory as the enemy found itself engaged on multiple fronts against some of its former vassals).

Bigger question than "how many troops on the ship?" is "how many troops are deployed?" along with "how long are they supposed to operate?"

The way I envision a Terran planetary attack it begins (after securing a foothold in orbit by fleet action) with using orbit-launched drop-troops (the elite of the Terran Guard - the elite of the elite) to seize a beachhead and strike key enemy installations, followed by the landing of Terran Guard line elements in the newly-secured LZs to widen the operation. Finally, after 1-3 weeks of fighting, the slower troop transports bearing Colonial Army forces land in the now-expanded LZs and offload a much larger infantry and armor force.

Plus, are they leg infantry? grav-mobile? grav-assault? I have a huge spot in the TOE for leg infantry because they are so much easier to transport - and that is also why I was thinking of "grav-cav" (gravbikes or similar), much easier interstellar transport.

Terran Guard are grav-mobile - each 12-man squad carried inside a G-Carrier which has free-flight capabilities. Scout elements use grav-bikes. This functions a bit more like "air-cav" in the real world (i.e. infantry transported by helicopters) more than regular mechanized infantry.

Terran Guard units are thus grav-infantry supported by fully air-mobile light grav-armor elements (one battalion of grav-gunships per regiment? One company per battalion?). Fire support is mainly provided by the grav vehicles (both G-carriers and grav-gunships), and much of the artillery support is by ortillery from orbiting ships. These are elite forces and are both highly mobile and possessing heavy firepower (both in the form of infantry weapons and in the form of heavily-armed grav vehicles).

Colonial Army units are in most cases leg infantry supported by tracked armor with some grav-based air support, though some forces are mechanized in wheeled APCs. They also have ground-borne artillery.

With the side question, is their initial equipment load for X weeks included on the ship, or sent on a separate ship that travels alongside?

Heavy resupply is provided by slower and bigger ships so the unit should be able to function several weeks (typically at least a month including operational margin) on supplies carried by their own ship before resupply arrives.

IMTU (a relatively Small Ship universe), Army troops are generally deployed in Battalion-sized units, and some with what is supposed to be a three-month supply. COACC comes on a separate ship. Special Op missions (with all those drop troops) move fewer troops, faster - and the Marines are the real RDF (usually in a company, people worry when a Battalion of marines gets deployed).

Similar to my Terran Guard though due to LBBs 2-3 tech restrictions the units are somewhat smaller - usually one company per 1,000 dton ship unless using low berths.

 

[Golan2072]

I'm considering reducing the squad size from 14 (3 fireteams + G-Carrier crew) to 10 (2 fireteams + G-Carrier crew) to make room for additional supplies on the G-carrier and also to increase the number of maneuver elements carried aboard the transport.

 

[rancke]

I'm considering reducing the squad size from 14 (3 fireteams + G-Carrier crew) to 10 (2 fireteams + G-Carrier crew) to make room for additional supplies on the G-carrier and also to increase the number of maneuver elements carried aboard the transport.

Either the G-carrier crew is separate from the squad they give a ride, meant to stick to the carrier rather than the squad, or they are part of the squad that is expected to leave the G-carrier and get down in the mud with the rest of them at need. So wouldn't 12 men (three fire-teams, with two (or three) of the men capable of driving a G-carrier) be better?


Hans

 

[Golan2072]

The G-Carrier also carries some support weapons, so it also provides fire-support for the troops - it's more of an IFV than "pure" APC (a bit like air-cavalry, no? Does the helicopter crew dismount in this case?)

 

[rancke]

The G-Carrier also carries some support weapons, so it also provides fire-support for the troops - it's more of an IFV than "pure" APC (a bit like air-cavalry, no? Does the helicopter crew dismount in this case?)

You have a point about the weapons. I was thinking more about a squad in the truck it had assigned to it.

A helicopter probably provides a better analogy. Is the helicopter crew part of the squad it carries?


Hans

 

[aramis]

I'm considering reducing the squad size from 14 (3 fireteams + G-Carrier crew) to 10 (2 fireteams + G-Carrier crew) to make room for additional supplies on the G-carrier and also to increase the number of maneuver elements carried aboard the transport.

You can see how I do the math - tho' I do crank it on a spreadsheet (Apple Numbers).

A 1000Td should be roughly a company if under military living conditions. (Double occupancy).

Oh, and if you cold-rack (low berth or fast drug) them, add 1Td per 10 men for kit (1.4 cubic meters each), making it 6 Td per 10 men...

 

[samuelvss]

The G-Carrier also carries some support weapons, so it also provides fire-support for the troops - it's more of an IFV than "pure" APC (a bit like air-cavalry, no? Does the helicopter crew dismount in this case?)

A crew never really leaves their vehicle unless it's inside a base or being abandoned; they may dismount, but only if they are still in control of their vehicle.

I think the M113 family is the "pure" APC with which we have had recent experience. The difference between an APC and an IFV, the way these terms are used is not who leaves the vehicle, but to what extent the crew, and sometimes the dismounts, fight from it: is it a weapon system, or an armed, armored transport. This is a matter of degree. An M113 was a classic APC. It was armed with a M2 .50 cal HB machinegun (or just a BMG for most of us), free-gun or retrofitted with a Snelling device for stationary engagements. It would have been folly to plan to fight mounted from a M113 on the high intensity heavy battlefield; if we we expecting to defend, the crew left the vehicle close by in defilade, dismounted the .50 and prepared to fight dismounted. They were never too far to quickly remount and haul donkey, however. In a mobile, fluid situation, the M1's did the fighting until the terrain became constrained, when they would overwatch and the dismounts would go out and beat the bushes. That being said, we planned and trained hard (ran gunnery tables like we were CDAT's and everything), to engage mounted in unexpected engagements, if it came to it. We would pop smoke and get out of dodge if it was anything heavier that a BTR (really, a Soviet wheeled APC), but against BTR's we could do some damage. Four .50's firing APIT, massed on a single target 400 meters away is a thing of beautiful terror... But these BTR's, APC though they were, were incapable of dismounting their 14.5 mm HMG's in any tactically-reasonable fashion so that the crew could fight dismounted.

Bradleys, on the other hand, are weapon systems, so the crew would never fight dismounted: Fire control, heavier weapons, heavier armor, and intended primarily as a weapon system, with the dismounts secondary. Bigger crew, fewer dismounts, who themselves spend more time doing maintenance on the Bradley.