tankers and refuelling

[kilemall]

Borders will depend on Oort existence- my house rule has Oorts largely gone for older stars, the idea being that they have been around long enough to either pull in everything and/or done enough close 'fly-bys' of other stars that have stripped out the cloud.

Otherwise, the emphasis has to be on intel work to get the critical advantage of catching tankers without the fleet, or fleet without tankers. You will otherwise be chasing after or hunkered down on defense of critical planets/facilities, or trying to impose your will/damage on the opposition with your own advance.

 

[flykiller]

When you need tankers to get from A to B, no.

well, obviously. but you describe no situation where the tanker is needed to get from a to b, you've simply described a process for saving time ...

Simply put, it takes a few hours to transfer fuel; it takes a few days to gather it and refine it.

... and not much time at that. an occasional few days saved after an occasional retreat jump doesn't seem worth a 33% reduction in combatants.

it's BASIC seapower doctrine.

sure it's basic seapower doctrine, but traveller ships are not at sea. a ship at sea can't dip a hose in the water and refuel, it either gets its fuel from a tanker or it sails back to port. a traveller ship however can get its fuel from numerous sources in the field. a tanker 1) adds little to this capability and 2) greatly reduces available fleet combatants.

 

[flykiller]

my house rule has Oorts largely gone for older stars, the idea being that they have been around long enough to either pull in everything and/or done enough close 'fly-bys' of other stars that have stripped out the cloud.

I like this rule - it adds to the tactical environment (or would, if anyone would play a jump game) - but I don't think it's justifiable. we're told that our star has been around for 5 billion years and various websites wax eloquent about the presence of "billions of comets" in our oort cloud, a few billion years more likely would make little difference.

(actually, some websites state that the existence of the oort cloud is unproven.)

You will otherwise be chasing after or hunkered down on defense of critical planets/facilities, or trying to impose your will/damage on the opposition with your own advance.

read sun-tzu.

 

[Brandon C]

in what way? a combatant gets fuel from a tanker faster than it can get it itself?

Personally, I think it would be faster than gas giant skimming but not much faster than refueling from ice or liquid water.

and the combatant cannot?

A battleship skimming from a gas giant is a battleship out of the fight.

OTOH, a refueling tanker needs more escorts than a refueling battleship.

There is a valid approach, though, to requiring all warships in a fleet to be capable of wilderness refueling.

wouldn't it be more efficient to build more combatants than 50% tankers?

Depending on the rule set, one warship of X tons may have the same cost and crew requirement as 2-5 tankers of X tons each. A lot depends on where that breakpoint is at.

 

[flykiller]

Depending on the rule set

always an issue.

one warship of X tons may have the same cost and crew requirement as 2-5 tankers

imtu I decided to separate hull from hull component in construction. a 10k warship and a 10k support ship no longer take up equal amounts of yard capacity, they now take up 10k each plus their individual components (including armor). this makes construction of simpler ships faster and cheaper in terms of yard capacity.

 

[pendragonman]

sure it's basic seapower doctrine, but traveller ships are not at sea. a ship at sea can't dip a hose in the water and refuel, it either gets its fuel from a tanker or it sails back to port. a traveller ship however can get its fuel from numerous sources in the field. a tanker 1) adds little to this capability and 2) greatly reduces available fleet combatants.

Mahan's doctrine was based on the observation of centuries of Naval warfare, not just the age of steam and oil. Those doctrine's held true regardless of powersource.

Spare parts are spare parts. In the age of sail you couldn't always get the right kind of cordage, or canvas, or precision parts (like block and tackle) just anywhere, and every navy "worth their salt" had supply ships that were a significant portion of their tonnage.

It wasn't until the age of steam and oil that navies needed colliers/tankers IN ADDITION TO, not as replacements of, their supply fleets. Hauling fuel put additional strain on the logistics, not reducing it.

Bottom line is that there is no such thing as a warship that at some time does not need replenishment.

Flykiller, look at any time in naval history, all the way back to rowboats if you want. At some point the warship needs food/fuel, spare parts, replacement crew, and expendable ordnance. They just do. Even if it means stopping on some deserted Island and making the parts you need out of local products. To continue to deny this fact and your derision of this idea why I dropped out of your field tests.

The reason people refer back to the age of sail so much is that the jump protocol, with its week of travel, is equivalent to the sailing time from London to (insert cross ocean destination here). And sailing fleets required logistics.

The only fleets that don't need logistics support are those that are designed for the tourney environment. A board game. Wooden Ships and Iron Men. If it is a campaign setting at all, then some sort of logistics are required.

 

[flykiller]

Spare parts are spare parts. In the age of sail you couldn't always get the right kind of cordage, or canvas, or precision parts (like block and tackle) just anywhere, and every navy "worth their salt" had supply ships that were a significant portion of their tonnage.

completely agree. but the discussion is about fuel, not parts. there is no reason for a fleet to jump to the oort cloud for parts and no reason to skim gas giants for parts and no reason for a supply ship to be separated from the fleet looking for parts.

Hauling fuel put additional strain on the logistics, not reducing it.

it sure did. that is because fuel has to be hauled, or naval ships don't have it. traveller ships can refuel in the field.

Mahan's doctrine was based on the observation of centuries of Naval warfare

while the doctrine has applicabilities, the equivalence is not one-for-one. traveller is not "sea-going-navy in space".

 

[kilemall]

I like this rule - it adds to the tactical environment (or would, if anyone would play a jump game) - but I don't think it's justifiable. we're told that our star has been around for 5 billion years and various websites wax eloquent about the presence of "billions of comets" in our oort cloud, a few billion years more likely would make little difference.

(actually, some websites state that the existence of the oort cloud is unproven.)

Hmm, well as long as we don't have jump/gate/warp or generational travel/ansibles, we don't know what is 'normal' yet, and so any of our assumptions and system models are as much entertainment artifice as science.

IMTU Barnard's Star ends up without one due to it's age, no gas giant either, and so the primary refueling is planetary ice.

No starport to speak of since there is nothing down that arm as of yet, so there is a martial arts monastery out there where the acolytes haul ice by human powered sled as part of their training and conditioning to pay the bills.

read sun-tzu.

Sun Tzu says many things, some of which would be contradictory in terms of our conversation and whatever you are driving at.

At some points Sun says to seize something the enemy wants/must have and await him at your leisure, to capture forces and supplies to feed on the enemy, at others he defines certain situations as contested ground, death ground etc. and consuls what to do in each "terrain/communications potential/enemy approach" combination, some of which is to run others to fight.

But above all he makes clear that war is a dangerous ruinous business and you better stack the deck with the best intel you can buy.

So best you make clear which parts of Sun you are alluding to, because that subject can go in many different directions.

 

[flykiller]

you better stack the deck with the best intel you can buy.

ah. and what is it we're missing about the next system over?

Sun says to seize something the enemy wants/must have and await him at your leisure

(grin) yes. why?

 

[whartung]

Canonically, fleets refuel at Gas Giants and via ocean dipping. There's simply not a lot of discussion about scavenging belts and clouds for snowballs.

If fuel were completely ubiquitous, then the general meme of fuel scarcity (Jump requirements, SDBs lurking in gas giants, then entire definition of "High Guard", etc.) would not pervade fleet concepts and fleet tactics in the Traveller.

But it does.

So, all this suggests that harvesting fuel from ice farming random comets and asteroids is impractical and unreliable. If "everyone could do it", then "everyone would be doing it". But, apparently, "nobody does it". Instead they fight for their fuel as a general rule. Securing fuel is important in campaigns. It wouldn't be if it was free to safely take.

Operational strategy is based around the 2 week response time to an attack. When a fleet arrives in a system, the fleet has 2 weeks of impunity before the opposition can react to the presence. Sure, there's always the chance of forces entering a system at any time, but those forces won't be coming as a reaction to the incoming fleet (barring an intelligence failure that predicts their arrival).

As a general rule, fleets rely on strategic surprise. They strike places where the opponent isn't massing their fleet. They bring "enough fleet" to conquer anything expected within the system.

That 2 week response window gives the attacking fleet time to gather, time to refuel, and time to strike.

The dynamics of refueling affect the need or not for tankers. If fuel is free to take, then there's no reason to bring tankers, save to hope empty space. Certainly no reason to bring them with the battle fleet.

If tankers can fuel the fleet faster than living off the land, then theres a tactical advantage to bring tankers with the fleet, top the fleet off, let them proceed deeper in to the system to attack, while the tankers refuel off the land. This lowers the response times of the in system opponents.

If an attacking fleet can jump in to an asteroid field, the fleet can likely mass well before an ad hoc response can maneuver from within the system, and the combat ships can simply delay fueling operations while fighting any defenders off. But even "tanks dry", ships are combat capable as soon as they arrive, as it's typically the jump tanks that are dry.

And, again, of course, if defenders respond, the attackers can forego fueling, bypass the defenders (perhaps trading a quick shot as they fly by) and attack the fixed targets the fleet was likely looking to secure in the first place.

Maybe fueling isn't that big of an issue, becoming routine, with the remote possibility of disaster.

 

[Condottiere]

Deterrence is the greatest form of the art of war.

 

[kilemall]

ah. and what is it we're missing about the next system over?

Perishable actionable intelligence on precise fleet locations, status and heading.

The kind of intel I am thinking of is not so perishable- war aims, plans, strategy, how the commanding admiral and subordinates think and operate, and advance intel on actions that tip their hand or timing- such as say when and where that tanker fleet is going.

(grin) yes. why?

To await the enemy with your full strength while he hurries to a place of your choosing and likely with less then his full strength, which does not allow him to do the same to you. To dictate the place and potentially the terms of engagement.

 

[pendragonman]

it sure did. that is because fuel has to be hauled, or naval ships don't have it. traveller ships can refuel in the field.

while the doctrine has applicabilities, the equivalence is not one-for-one. traveller is not "sea-going-navy in space".

So every warship you design has the following:

1) at least partial streamlining. This implies no open structure, planetoid, or buffered planetoid vessels.
2) Scoops
3) Bins
4) Processors

because otherwise you need tankers or "scoop ships" to scoop enough fuel for your fleet to process for refueling.

Of course, you could just use unprocessed. I wouldn't, but I know that tankers are necessary. You clearly do not.

 

[kilemall]

Deterrence is the greatest form of the art of war.

I don't think so, but if you believe that the Moists are your guys.

http://earlyworldhistory.blogspot.com/2012/02/mozi-chinese-philosopher.html

https://en.wikipedia.org/wiki/Mozi

https://en.wikipedia.org/wiki/Mohism

 

[flykiller]

So every warship you design has the following:

1) at least partial streamlining. This implies no open structure, planetoid, or buffered planetoid vessels.
2) Scoops
3) Bins
4) Processors

sorry citizen, state secret, need-to-know basis only.

I know that tankers are necessary. You clearly do not.

at this point we can allow the readers to decide for themselves.

 

[aramis]

sure it's basic seapower doctrine, but traveller ships are not at sea. a ship at sea can't dip a hose in the water and refuel, it either gets its fuel from a tanker or it sails back to port. a traveller ship however can get its fuel from numerous sources in the field. a tanker 1) adds little to this capability and 2) greatly reduces available fleet combatants.

The tactical imperativs of space warfare are, quite literally, identical to those of littoral warfare. It's not like modern wet-navy vessels can crack seawater for power, either.

And, if there is available hydrogen ice, you can always send guys out with laser rifles to carve chunks off to fit inside an unused vehicle bay, heat it to liquid, and pump it elsewhere.

If you can get to the oort, you have access to fuel. In exactly the same way as icy asteroids (see beltstrike).

 

[kilemall]

The tactical imperativs of space warfare are, quite literally, identical to those of littoral warfare. It's not like modern wet-navy vessels can crack seawater for power, either.

Oh. I don't know about that.

http://www.altenergy.org/new_energy/seawater-into-jet-fuel.html

 

[Magnus von Thornwood]

On Oilers (AO).

I have seen the question raised as to the speed which an Oiler can refuel a Capital ship versus skimming or dipping.

Looking it up to make sure I had my numbers straight as of T5.09, page 385, we have 1 ton TL-A (10) Transfer Pump which can transfer 100 tons of Fuel to the Power Plant in seconds. Now, if we have that then having the Transfer Pump move that Fuel to an on-board Fuel Tank for later use seems pretty plausible to me.

That said I tend to go with Oilers being way faster than skimming and dipping, plus they come with on-board Purifiers, Mining Buggies, and Fuel Cutters which means they can haul out to the deep system and spend the battle tanking up for the next wave or to refuel everyone at the rally point.

So, put me down in the Oort and Oilers crowd.

 

[warwizard]

Tankers IMO are needed if you are not already in extremis as were the IJN when they sent the fleet out to battle without enough fuel to return. They flat out did not have the fuel for the return trip regardless if they had the tankers.

Now the goal of a fleet admiral when planning an attack into a system is to figure out a method such that his current assets can make the attack and withdraw by jump if the enemy forces are able to deny access to quick fuel sources, such as A and B star ports, gas giants and planets with liquid surface water. Less desirable fuel sources are comets and ice asteroids which have a much slower rate of being on boarded and converted to LHyd. generally mean that it is a busted operation and they can expect enemy task forces to be preparing ambushes in nearby systems.

Compare a battleship floating down on anti-gravity taking 6 hours to land on a planet then lower a 100cm pipe into the lake or ocean it landed in and turning on the high capacity pump and using the power from the fusion power plant to crack the water nearly as fast as they can pump it aboard, to drifting near to an asteroid and sending out all it's small craft with working parties to transfer loose "snow" into the holds and then when it's melted down to liquid , it's only 5% of the hold is full of water. In this case the battleship may take weeks to obtain enough fuel to enable a jump, whereas a scout ship might be able to do it in a few days. Note they would need weeks without enemy harassment, which would generally be obtained really far out such that they can hide.
(Not inviting the hiding debate here, this is MY opinion, ships CAN hide given enough distance, and if we are talking oot clouds there may be entire planets that may be out there and unseen for the million years they take to move from 75 billion km to 25 billion km orbit. (apogee and perigee).)

 

[esampson]

. . .Compare a battleship floating down on anti-gravity taking 6 hours to land on a planet then lower a 100cm pipe into the lake or ocean it landed in and turning on the high capacity pump and using the power from the fusion power plant to crack the water nearly as fast as they can pump it aboard. . .

Assuming a planet similar to Earth in gravity and atmospheric density a battleship shouldn't take 6 hour to land on a planet. They would come in with a relative orbital velocity somewhere in the neighborhood of 0, descend at a relatively steep angle and brake with the engines.

You can work out the ship's airspeed at any altitude by using the formula V=9.8*G*(A/(G*4.9))^(1/2) where G is the acceleration of the ship, A is the altitude in meters, and V is the ship's speed in meters per second. At 20km a ship undergoing 1/2G of deceleration would be travelling at around 1500 kph. Because the atmosphere is only 10% what it is on the surface it would have the same air resistance as a ship travelling at about 500 kph at sea level. It would also cross 20 km to touchdown with a final velocity of 0 after 90 seconds.

500 kph does feel like it might be a little high, especially if the ship is not well streamlined, but you can adjust to even lower rates of deceleration so that the speed at 20 km is lower. It will take longer to touch down but unless you really throttle it back (to deceleration rates of less than .05 G) you are looking at times of 5-10 minutes, not 6 hours.

Because the air is much thinner as you go up you can decelerate much more rapidly as you approach the 20 km line so that you drop the ship down to safe speeds for atmospheric flight. As a result additional distances could be closed extremely rapidly.

To give a very conservative estimation a 2G capable ship would need just under 7 minutes to go from 200 km above the surface to a landing with a relative air resistance of 160 kph reached at 20 km. It would decelerate at 2G for 130 seconds as it traveled from 200 km to 20 km and it would then decelerate at .05G for another 285 seconds until it touches down. In all likelihood a military craft in those conditions would be capable of travelling significantly faster at 20 km (nearly all modern aircraft would actually stall at that speed) and probably has a 3-4G engine, so it would be even faster touching down.