Auxiliaries and Support Ships

[Vladika]

As I already told in another thread time ago, I've always envisioned the same courriers being used as scouts. If we asume a TL 13 fleet with J4 courriers, its mision (as scouts) would be to jump at J2 from the main fleet, appearing in the middle of nowere in the target system (in our own system a good place could be between Earth and Mars orbits, out from the current route among them, just to avoid random enounters), and scan for signals and intelligence.

As they will still have fuel for another J2 (I asume CT with jump governors), it could jump away for a randez-vous with the main fleet (with the intelligence collected) at short notice, should that be needed.

For a TL 15 fleet (with J6 courriers and J4 main fleet), it could jump 2 parsecs away from main fleet position (if the main fleet performs J2, it would perform J4 to achieve it) and still be fueled for return trip.

For longer scouting, drop tanks could be used from the main fleet (here your courrier tankers could help) to keep them fueled at the scouting target.

Using the same ship in two roles helps standarization, even if a little less specialized (in this case I guess this hindrance would be qminor, nearly negligible).

I think in the case of "extra" tonnage on the Battle Tender (meaning NOT enough to carry another Battle Rider), I would implement your previous ideas. However, I wouldn't sacrifice a major combatant to gain that space. A Tender can carry a Rider; not so the run of the mill auxiliary.

One major reason for auxiliary and support ships is to "go for the beer and groceries", allowing the combatants to remain on station.

I'm curious as to the extent of cultural bias that may slip in to these discussions. I, coming from America, tend to think in a real world, global extended mission fleet. Some of the European countries don't have that "world mission" mindset, or ability. I see many specialized ships needed to come and go, keeping a large fleet at sea. Do you see smaller fleets, or single ships, operating closer to home as a current world view?

I know we both know better in a Traveller context. But, do our views differ from cultural bias or necessity?

 

[McPerth]

I think in the case of "extra" tonnage on the Battle Tender (meaning NOT enough to carry another Battle Rider), I would implement your previous ideas. However, I wouldn't sacrifice a major combatant to gain that space. A Tender can carry a Rider; not so the run of the mill auxiliary.

Neither will I sacrifice a BR for a tender to carry auxiliaries, but IMHO they are at different leagues. I guess a Tender capable to carry 7 30 kdton BRs will probably have some tonnage to spare to carry also some 200-400 dton of courriers without having to sacrifice the BRs complement, like a carrier can carry some liaison aircrafts without sacrificing its combar air wing.

One major reason for auxiliary and support ships is to "go for the beer and groceries", allowing the combatants to remain on station.

Nevr said those will not be necessary, only that, as much as posible, they have to be kept out of the front lines. Of course, no matter how many spares and supplies a BT carries, they will run out on the long run, and some replenishement will have to exist. But the spares and supplies for immediate fleet opperations, are, again IMHO, better carried on the same Tender.

After all, if the squadron losses its tender, the supplies and spares lost are not their biggest problema, while if they lose some freighters it can be, and freighters use to be less defended. In some wais, I guess my docrine is closer to "put all egs in a single basket and watch it well".

I'm curious as to the extent of cultural bias that may slip in to these discussions. I, coming from America, tend to think in a real world, global extended mission fleet. Some of the European countries don't have that "world mission" mindset, or ability. I see many specialized ships needed to come and go, keeping a large fleet at sea. Do you see smaller fleets, or single ships, operating closer to home as a current world view?

I know we both know better in a Traveller context. But, do our views differ from cultural bias or necessity?

Sure cultural biases affect our mindset, not only because we're from different countries, but because we come from different background. While you have a military background, the closer to militry opperations I've ever run are with little pieces of carton over a map. In any case, this could lead too easily to a political discussion about the role of the various armed forces arround the world...

In the case of Traveller, I envision offensive opperations away from the main supply lines, in the way Sabredog tells, and IMHO the more you're tied to those auxiliary supply lines, the more complex those offensive thrusts become and the harder for them to be successful.

That's why I stress the organic repair and resuply capabilities, in an environemnt where your HQ will not be sure about your position and any asking for anything (ressuply, reinforcements, etc) will take weeks to reach it, as will any orders this same HQ gives for your asking to be fulfilled.

This would be quite more complex in a small ship universe, where ships are not able to have space for the many functions I expect from a tender, and so more specialized ships would be needed (as was partially discussed in the discussion about the hospital ship I quoted at the begining of this thread).

 

[Timerover51]

In the case of Traveller, I envision offensive opperations away from the main supply lines, in the way Sabredog tells, and IMHO the more you're tied to those auxiliary supply lines, the more complex those offensive thrusts become and the harder for them to be successful.

McPerth, you NEVER NEVER EVER conduct major offensive operations away from the main supply line. Given the jump drive restrictions in the Traveller Universe, your main supply base cannot be more than one or two jumps away from your offensive point, presumably a planet. Any campaign in Traveller is going to resemble the campaign in World War 2 across the Pacific with a continual movement of the main supply bases forward, and replenishment convoys arriving at the fleet resupply point on a regular sustained basis. During World War 2, aircraft carriers only carried enough aviation fuel and aerial weapons for 2 to 3 days on intensive operations. Groups were continually rotating back for underway replenishment from the Fleet Supply Train.

If you are jumping a fleet to a system without a gas giant, you are going to have to have your refueling tankers jump in as well, and given that some of the ships in Fighting Ships, Supplement 9, need 190,000 plus tons of Liquid H for jump and maneuver, your tankers are going to be enormous ships too. At that point, the target for the opposition is not your battle fleet, but the tankers supporting it. Kill those and the ships are in an enormous world of hurt.

I was trained in the Army as a supply and logistics officer, and I have continued reading on the subject for 38 years. I have also read the US Army histories of World War 2 covering Global Logistics and Strategy, the histories of supplying the various theater of operations and what it took, along with studying the US Navy's supply operation in the Pacific, to include to pre-war war plans where one of the major focuses was building up a fleet train to support offensive operations. I have also studied the logistics of the German campaign in Russia, and the abysmal lack of understanding of logistics on the part of the Japanese Imperial General Staff.

Given that knowledge, I have a less than enthusiastic view of massive interstellar fleet engagements in the Traveller universe, along with any form of successful planetary invasions of a high-population planet with a high tech level. Logistically, they just do not compute.

I repeat the old but for the most part true comment:

Amateurs talk strategy and tactics, professionals talk logistics.

 

[Condottiere]

I've come to the conclusion that in Traveller there's actually a greater emphasis on low tonnage marauders and ships, in order to keep the logistics tail as small as possible.

 

[Timerover51]

I've come to the conclusion that in Traveller there's actually a greater emphasis on low tonnage marauders and ships, in order to keep the logistics tail as small as possible.

That depends on what version of Traveller you are running or using. The first post specifically said that the discussion would include:

I'd prefer CT/HG2/TCS but any Traveller rules set would be fine. Please note which rules set you are discussing in each post so as to be relevant to all readers/posters.

High Guard, 2nd edition and Trillion Credit Squadron (TCS) assume large ship universes, while Classic Traveller tops out at 5,000 Traveller Displacement Tons. Logistics are a bit easier in a small ship universe than a large ship one, primarily because of the enormous quantities of fuel needed in a large ship universe.

My personal preference is for a small ship universe, one of the reasons being the logistics issue.

 

[rancke]

High Guard, 2nd edition and Trillion Credit Squadron (TCS) assume large ship universes, while Classic Traveller tops out at 5,000 Traveller Displacement Tons.

The OP probably meant it the same way you do, but CT is a misnomer, since both HG and TCS are CT too. Book 2 it is that tops out at 5,000T. If anything, HG and TCS are more CT than Book 2, since they superceded it (Except for the bits that were grandfathered).


Hans

 

[flykiller]

And finally folks will see the critical need for other than front line combatants, particularly in a campaign setting.

"finally"?

(this may be a little abbreviated ... also while my designs are based on hg/tcs, ultimately they are for use in grand high admiral so they may not exactly fit hg/tcs conceptions)

alice-class fleet transport ship

the alice is a general purpose transport ship meant to handle most fleet auxilliary needs. the 19kdton ship itself is standard and independent across all usages and varies only by its 4900dton module which can be of any internal configuration. the alice is j4 m2 with minimal combat capability and no added armor. the ship hulls and basic drives are manufactured by porozlo, with higher-tech components supplied by other yards such as the lunion/strouden cosortiums. the modules are supplied by the junidy yards and outfitted as needed by imported components. these ships largely remain with the rider transports and seldom have any reason to be elsewhere.

hull, maneuver drives, power plant, fuel purifier - tech 10 (porozlo, minor yards)
bridge, sensors, weapons, screens - tech 15 (as available)
jump drives - tech 13 (lunion/strouden, efate, palique)
cargo module - tech 9 (junidy, minor yards)

19000 dtons (less 4900 dton module)
prolate spheroid (module included), streamlined

crew
command 14
engineering 47 (10% overmanned)
gunnery 10 (10% overmanned)
service 12
troops 4
flight 3
medical bay, brig, extra staterooms, 10 lowberths

engineering
sensor suite 9
jump 4
maneuver 2
power plant (sensors + jump 4)
fuel purifier
cargo (4% - 10 months endurance)

weapons
4 fact 9 beam laser batteries w/backup power

defenses
armor 0+2
nuc damper 9
1 fact 9 sandcaster battery w/backup power
6 standard damage control stations

vehicles
2 ship's gigs
3 lifeboats

other
4900 dton module, form-fitted for attachment to alice
armor 0+1

available modules

marine battalion
one marine battalion plus all support services and vehicles

fuel
4600 dtons of fuel tank, plus tech 9 fuel purifier

cargo
4900 dtons of space

maintenance/repair
personnel facilities and cargo for general purpose ship annual maintenance and combat-related repair

hospital/rescue/recovery
personnel facilities and cargo for major medical services including normal and combat-related casualty retrieval/treatment. also used for medical missions in various outworlds.

in peacetime a battlegroup will be accompanied by one hospital alice and one maintenance alice. in wartime a battlegroup may have an additional maintenance alice and a fuel alice. in supported offensive operations the battlegroup will have one marine battalion, two hospital alices, six maintenance alices, five fuel alices, and cargo alices as required.

 

[aramis]

McPerth, you NEVER NEVER EVER conduct major offensive operations away from the main supply line.

:

tell that to then Brigadier General Pershing... who simply took enough for 6 weeks and performed a recon in force. Naval units, likewise, often operate away from supply lines for months. the ability to carry 6+months with makes it very different from army logistics.

Note that Traveller ships don't need to have fuel via supply chain. .. they can skim when away from from supply chain. Tankrons are not for range as much as speed as for the ability to refuel between jump in and first intercept so that you can jump out if losing, and for rescue after a short jump. Also, for the rare "hot fuel only" systems.

 

[Timerover51]

tell that to then Brigadier General Pershing... who simply took enough for 6 weeks and performed a recon in force. Naval units, likewise, often operate away from supply lines for months. the ability to carry 6+months with makes it very different from army logistics.

Naval units carry 6 months worth of fuel, without refueling? Interesting. Six months worth of food and ammunition as well?

Pershing was taking a column into Mexico chasing what we called "bandits", not facing a major military opponent. He also was using horses, and depending on local forage for them, with limited mechanical transport. I would need to check and see how much of a supply train he had with him.

Hmm, found my PDF copy of

PUNITIVE EXPEDITION REPORT By Major General John J. Pershing, Commanding the Expedltion.

, date of the report is 10 October 1916.

The following from page 35 of the report.

The successful handling of supplies by truck trains for an expedition operating over a long line of communication has been steadily and gradually developed to a degree never before attained in our service. The greatest praise is due the officers charged with these tasks, and the results again prove the well known resourcefulness of officers of the regular army. No doubt these experiences will be made the basis of energetic efforts in anticipation of possibly greater emergencies.

The continual change in the situation and the number of troops at different points along the line of communications made it difficult to anticipate necessities. There was as often too much as too little. Troops stationed along the line of communications were fairly well supplied, but troops operating at the extreme front for the first month literally lived off the country. When the advance columns left Dublan they had only what remained of the five days' rations carried by pack trains with which they started from Culberson's Ranch. Fortunately plenty of cattle were to be found in the country and a limited amount of corn and hiexican beans could usually be procured. Colonel Brown's squadron of the 10th Cavalry received no rations from the time it left Dublan on March 19th until rations were sent south by pack train to Santa Cruz near Parral about the middlo of April. While supplying the current needs of the command in general, it was also imperative to provide against extraordinary field service as well as against the probability of impassable roads during the rainy season. In addition to providing regular rations, one hundred thousand rations were accumulated at convenient points and held for emergency. Later a greater variety was furnished, while at present the most liberal supply is being provided.

My emphasis added. One hundred thousand rations would have weighed on the order of 400,000 pounds, or 200 tons. Pershing did devote a large number of troops to maintain his supply line back to the US. Do you wish me to post the exact units? Would you like me to email you the entire report? Note, anyone interested in the entire report can contact me with their email address and I will send it to him. It is in PDF format, and is 6.7 MegaBytes.

 

[aramis]

Naval units carry 6 months worth of fuel, without refueling? Interesting. Six months worth of food and ammunition as well?

Pershing was taking a column into Mexico chasing what we called "bandits", not facing a major military opponent. He also was using horses, and depending on local forage for them, with limited mechanical transport. I would need to check and see how much of a supply train he had with him.

subs routine carry 5 years of fuel, 12 months of routine lubricatoon & filters, and 6 to 9 months food. It is estimated that they could remain underway eith food resupply teice a year for 8 to 10 years, with declining perfofmance after 6years.

A standard nuke ship plant is 5 years before refuel & deep maintenance, with supplies for 3 months aboard, and most capable of stowing 6 months food. Diesels routinely refuel monthly, but most have bunkerage for more, and provisions for at least 45 days food storage.

Note that for morale, more frequent food supply is used to allow both more variety and more fresh foods, and SOP is to refuel in port every port hit. Mostly to allow for maximum deployment readines.

Aviation units afloat usually have far less than a week of full operations on their carrier, but the group has 2+ weeks of aviation fuel, specifc amounts classified.

by comparison, the average armored column needs weekly supplies.

The average Traveller ship can, like Pershing's horses, fuel from wild sources.

 

[Timerover51]

subs routine carry 5 years of fuel, 12 months of routine lubricatoon & filters, and 6 to 9 months food. It is estimated that they could remain underway eith food resupply teice a year for 8 to 10 years, with declining perfofmance after 6years.

A standard nuke ship plant is 5 years before refuel & deep maintenance, with supplies for 3 months aboard, and most capable of stowing 6 months food. Diesels routinely refuel monthly, but most have bunkerage for more, and provisions for at least 45 days food storage.

Note that for morale, more frequent food supply is used to allow both more variety and more fresh foods, and SOP is to refuel in port every port hit. Mostly to allow for maximum deployment readines.

Aviation units afloat usually have far less than a week of full operations on their carrier, but the group has 2+ weeks of aviation fuel, specifc amounts classified.

by comparison, the average armored column needs weekly supplies.

The average Traveller ship can, like Pershing's horses, fuel from wild sources.

How long is it going to take to refuel a ship requiring 190,000 tons of Liquid H from a gas giant? And what if there are NO WILD RESOURCES? I did not quote the entire report of Pershing.

As for an Armored column, they are resupplied DAILY, not weekly. A Modern Armored Division in the attack needs 1,000 tons of supplies daily. Very rarely do any war games, including some of the ones run by the military, consider the problem of combat resupply.

As for Nuke subs, I had two brothers riding them. One on a Fleet Ballistic Missile boat, and one a Nuke Attack. After a couple of months underwater, morale started to go downhill on the Boomers. With the nuke attacks, the biggest problem was abrupt deployments for extended periods. The married crew were not happy when they got back and discovered their wives were now pregnant. And I was unaware that all of our USN ships were now nuclear-powered.

Most ships have a specified range at a specific speed, generally 18 to 20 knots cruising speed. Normally, that range is about 300 to 400 hours. In the RN, most of the frigates have a range of 4000 nautical miles at 18 knots. That is, at best, 9.5 days, not several months. Standard policy is to refuel at 50% fuel capacity. US ships are going to have a longer range, but fuel is not going to stretch for 30 days, much less more than that.

Traveller star ships are either going to burn up their fuel supply jumping into a system and then praying that they can resupply with fuel so they can jump out, or they are going to have to jump at half of their potential range so they can jump back out of a system. Are you telling me that a Fleet Commander is going to jump his/her entire fleet into a system with no, as you put it, "wild resources", and gamble that he can win whatever battle he/she has to fight and then refuel so his/her fleet can jump out of the system?

 

[McPerth]

McPerth, you NEVER NEVER EVER conduct major offensive operations away from the main supply line. Given the jump drive restrictions in the Traveller Universe, your main supply base cannot be more than one or two jumps away from your offensive point, presumably a planet.

That would mean a Traveller space war (as FFW or Solomani War) would be a postional war, more likely the camapigns in the Thirty Years War, where an entire camapign could be centeres on a dingle siege, than the deep thursts shown in Traveller canon, that are more alike WWII armored thrusts...

This a true possibility, as there are some semblances to it too:

• your main troop/fleet concentration is in one place, instead of a contiuous front...
• battles were located at a place, instead of continuous fighting along that front
• lack of instant communications (and so outdated intelligence)
• key points to bessiege/assault centering the campaigns (cities in TYW, planets in Traveller)
• difficulty to take replacements to the front
• etc...

But I guess it's a change of the vision most of us have about those space wars. Never thought about this before, I must admit...

Any campaign in Traveller is going to resemble the campaign in World War 2 across the Pacific with a continual movement of the main supply bases forward, and replenishment convoys arriving at the fleet resupply point on a regular sustained basis. During World War 2, aircraft carriers only carried enough aviation fuel and aerial weapons for 2 to 3 days on intensive operations. Groups were continually rotating back for underway replenishment from the Fleet Supply Train.

I've also made this comparison myself, and I've always thought the computer game Gary Grigsby's Pacific War could be adopted for those wars, but there are also key differences (mostly, once again, lack of instant communications and outdated intelligence):

• In PW, you had enough time window to attack a convoy from the momento you detected it (usually by submarine pickets or reccon planes) to send your airplanes to attack it; in Traveller, once your pickets detect a convoy, it would be at least 2 weeks until your combat units may attack it, and it can well be 2 jumps away by then
• In PW, the same convoys have to cross the emptyness of the sea, being vulnerable along all the time they crossed it, possibly away from their fighter cover, while in Traveller they skip it, being only vulnerable when in real space, usually in friendly taken systems where some support is likely to be, so not relying only in their escorts.
• In PW the orders to fleet where obeyed in short notice, as would any change of orders (if you had a fleet/TF moveing and you wanted it to alter course, you could just radio them and they did it); in Traveller, this will take weeks

Not sure who will all of this benefit the most, but it sure alters the setting enough as to be more like age of sails camaigns, and in those campaigns ships were not so tied to their logistical pipeline.

My guess is that Traveller setting mixes both settings, and while the supply chain is needed, fletes are less dependent on it for (relativity) short periods, that in Traveller space movements are measured in weeks, and that deep thusts are posible, albeit with prior logistics build-up needed.

If you are jumping a fleet to a system without a gas giant, you are going to have to have your refueling tankers jump in as well, and given that some of the ships in Fighting Ships, Supplement 9, need 190,000 plus tons of Liquid H for jump and maneuver, your tankers are going to be enormous ships too. At that point, the target for the opposition is not your battle fleet, but the tankers supporting it. Kill those and the ships are in an enormous world of hurt.

Most systems have alternative refueling points (either oceans, ice commets, etc), so the lack of GG will slow you, but will not stop you outright. In any case, you're right tanker support will be the best option in those choke points.

 

[Condottiere]

Recalling the Battle of the Atlantic, I would think that a lot of the logistic ships would be heavily automated, not because I believe that the personnel can't be found to man them, but rather on the assumption that when enemy raiders slip through, loss of life would be minimal.

 

[McPerth]

Recalling the Battle of the Atlantic, I would think that a lot of the logistic ships would be heavily automated, not because I believe that the personnel can't be found to man them, but rather on the assumption that when enemy raiders slip through, loss of life would be minimal.

But automated ships will not be so able to deffend themselves. So, while you can cut your personnel losses this way, you're likely to increase your shipping ones. I'd rather foresee escorted convoys while giving the freighters some defense capacity by themselves (akin to Liberty ships).

 

[aramis]

How long is it going to take to refuel a ship requiring 190,000 tons of Liquid H from a gas giant? And what if there are NO WILD RESOURCES? I did not quote the entire report of Pershing.

A few hours. Under a day, per the rules.

Also: there are several cubic feet of Pershing's campaign records. According to one of the archivists from DC, pershing's final report does NOT jive with the archived daily reports. In general, do NOT trust a General Officer to be honest about his status. The dailies often get ignored, including by the general, simply because they are (1) until recently, not forwarded daily, and (2) overwhelming in detail about the details. Anyone who's been in the military has encountered the effect.

 

[Vladika]

Also: there are several cubic feet of Pershing's campaign records. According to one of the archivists from DC, pershing's final report does NOT jive with the archived daily reports.

This is in no way surprising. Most general officers read, or have read to them, a synopsis compiled, and abbreviated, by their staff officers.

In general, do NOT trust a General Officer to be honest about his status. The dailies often get ignored, including by the general, simply because they are (1) until recently, not forwarded daily, and (2) overwhelming in detail about the details....

Nearly every General Officer practices CYOA (Cover Your Own Ass) politics. Most, if not all, after action reports are pretty glossy.

Pershing would have whined about not getting enough supply, partly because it was all to true, and partly to impress higher up with his and his commands ingenuity.

One thing is for sure, given the day and age, with the primitive situation of transport and roads, or lack thereof, Pershing was never in full supply.

This thread has gone far afield of my original intent and I'm beginning to regret starting it.

Can we get back to proposed logistics in Traveller and possible rules for their use?

 

[Piper]

I'm beginning to picture an ever increasing size of dispersed structure jump frames that can be kitted out for mission specifics:

10kt - fighter/SDB
100kt - workhorse jump frame
1000kt - squadron support
10000kt - fleet support

The frames/tenders call them what you will can have sub craft added for mission specifics - sort of a LASH set up but with support vessels.

The really big frames are capable of moving a couple of Tigresses or the stuff needed to salvage them.

I

This is, frankly, brilliant.
It's the kind of idea that's so obvious in retrospect that it seems simple.
Hats off to you.

One idea that I've used with some success is the creation of a Forward Arming and Refueling point (FARP). I've prepositioned tankers and supply ships in an empty hex adjacent to the target system and assembled the strike force there. It can create some useful jump shortcuts, as well.

 

[rancke]

I'm beginning to picture an ever increasing size of dispersed structure jump frames that can be kitted out for mission specifics:

10kt - fighter/SDB
100kt - workhorse jump frame
1000kt - squadron support
10000kt - fleet support

The frames/tenders call them what you will can have sub craft added for mission specifics - sort of a LASH set up but with support vessels.

The really big frames are capable of moving a couple of Tigresses or the stuff needed to salvage them.

I thought the maximum size was 1 million dtons.


Hans

 

[aramis]

This is in no way surprising. Most general officers read, or have read to them, a synopsis compiled, and abbreviated, by their staff officers.



Nearly every General Officer practices CYOA (Cover Your Own Ass) politics. Most, if not all, after action reports are pretty glossy.

Pershing would have whined about not getting enough supply, partly because it was all to true, and partly to impress higher up with his and his commands ingenuity.

One thing is for sure, given the day and age, with the primitive situation of transport and roads, or lack thereof, Pershing was never in full supply.

Gen. Pershing was supposed to catch PV on the US side of the border... by his original orders. Noting that interdiction is MUCH harder than pursuit, and having been given (unlawful) orders from the president to violate Mexico and to act as if at war... a failure would have been "interesting times" for both Gen. Pershing and Pres. Wilson. Court Martial and Impeachment, respectively, would have been likely.

He'd have been doing CYOA by claiming to never have been out of supply... which would have been amongst the rationales for a Conduct Unbecoming charge. Even then, he wasn't "off the hook" just because he succeeded.

Pershing also was out of supply, but not unsupplied; he had supplies (and for the era, sufficient for an expedition - more than the Russian Expedition had). American Expeditions prior to WWII had constant supply chain issues solved by local supply "options" - raids, local contracts, allied nations' supply chains, and deployed supply depots/caches.

Which reminds me of another one of those historical supply line issues that crop up, and is clear adventure fodder... but also illustrates the differences between being unsupplied and out of supply line - a RIF is almost always outside the supply line, but may not be unsupplied.

For ground troops purposes in Traveller, once you're a jump away from supplies, you have no ability to know if you're still in supply, unless and until you establish local supply.

Pershing is one of those wonderful cases where success favored the bold - his incomplete supply line (and limited ammo, limited fuel, limited food, and lack of fodder) resulted in a drive to succeed IMMEDIATELY. A drive which will be VERY telling in Traveller, because your supply line is a two week lag, minimum, until you establish local supply. When you go in, you go in with overwhelming force.

Which means, essentially, that either you bring a factory along with, or you bring a major amount of supplies with, or both.

Invaders are likely to bring food, and to use lasers and plasmas in preference to slugthrowers, simply for supply chain purposes. An occupation force is going to bring a field munitions factory (probably a vessel containing one, really). Just like every civil war regiment had - the armorers, and often, the NCO's, could cast bullets in the field, and so only needed powder and a source of castable metal (usually lead, but sometimes others were used).

 

[Timerover51]

I am pretty much out of the discussion, having been warned about the use of real world expertise.