How many tankers and tenders per fleet?

[Condottiere]

The attacking Vulcan was refuelled seven times on the outward journey and once on the return journey. Grey lines indicate reserve aircraft to replace casualties.


During the 1982 Falklands War, Operations Black Buck 1 to Black Buck 7 were a series of seven extremely long-range ground attack missions by Royal Air Force (RAF) Vulcan bombers of the RAF Waddington Wing, comprising aircraft from Nos 44, 50 and 101 Squadrons against Argentine positions in the Falkland Islands, of which five missions completed attacks. The objectives of all missions were to attack Port Stanley Airport and its associated defences. The raids, at almost 6,600 nautical miles (12,200 km) and 16 hours for the return journey, were the longest-ranged bombing raids in history at that time.
The Operation Black Buck raids were staged from RAF Ascension Island, close to the Equator. The Vulcan was designed for medium-range missions in Europe and lacked the range to fly to the Falklands without refuelling several times. The RAF's tanker planes were mostly converted Handley Page Victor bombers with similar range, so they too had to be refuelled in the air. A total of eleven tankers were required for two Vulcans (one primary and one reserve), a daunting logistical effort as all aircraft had to use the same runway.

 

[AnotherDilbert]

Spaceships are not aircraft.

J-4 tankers can only make two J-4 without refuelling anyone. They can only extend range a little. They can, and are intended to, refuel unstreamlined ships from a nearby fuel source.

Example: We want to span a 6 Pc gap with a J-4 CruRon (8 × 50 kDt). The cruisers use their own 160 kDt fuel for a J-4 and need another 80 kDt for the remaining J-2. A 100 kDt tanker contains 80 kDt fuel, but uses 60 kDt of those itself, so can only provide 20 kDt each. We need 4 tankers à 100 kDt = 400 kDt to support 8 × 50 kDt = 400 kDt of cruisers at half again the cost as the cruisers...


If you really want to extend mission range you need drop tanks.

 

[kilemall]

Dilbert, I agree that they aren't going to do multiples of range increase like tankers to jets do, but I highly disagree that they are worthless for the purposes I am mentioning.


Surprise of not showing up around ANY refueling point in the first 4 parsecs, increase of effective expedition/raid start points of J-8 beyond the lines greatly multiplying the potential patrols needed to even be aware of the intruders, speed of refuel getting hours if not days ahead of any pursuit/reaction, these are priceless capabilities.

Then once this sort of operation is known to an enemy, you can start employing misdirection with tanker fleets that operate in a system and are spotted, but are not actually supporting a fleet and jumps back/ahead with the 'extra fuel' onboard.

An opponent then has to operate/patrol as though there could be a raider fleet even when there isn't, allowing for better concentration against less defenders.




Re: drop tanks, seems a waste of shipyard tonnage to me, but could allow more conventional mercantile/support ships to act as ersatz tankers and help strap on the tanks. This seems wasteful to me, of time if nothing else, the drop tanks would be better off being added to both the tanker AND the fleet for the initial jump, increasing the potential penetration range with a free jump built in while leaving the tanks to be collected and reattached at friendly bases preparatory to the next sortie.


Or they could be dropped off at a secret fuel dump for attachment at leisure to perhaps get the raider fleet back across the line once the responding hunters are closing in.

 

[McPerth]

Spaceships are not aircraft.

J-4 tankers can only make two J-4 without refuelling anyone. They can only extend range a little. They can, and are intended to, refuel unstreamlined ships from a nearby fuel source.

Example: We want to span a 6 Pc gap with a J-4 CruRon (8 × 50 kDt). The cruisers use their own 160 kDt fuel for a J-4 and need another 80 kDt for the remaining J-2. A 100 kDt tanker contains 80 kDt fuel, but uses 60 kDt of those itself, so can only provide 20 kDt each. We need 4 tankers à 100 kDt = 400 kDt to support 8 × 50 kDt = 400 kDt of cruisers at half again the cost as the cruisers...


If you really want to extend mission range you need drop tanks.

I'll use the tankers in a different way than you tell in your example...

If I have the fleet performing a J2 first, eahc cruiser will still have 10 KDt (and so only needs 10 KDt more to reach destination), while each tanker could provide 40 Kdt of fuel and then retreat to origin point to refuel and follow the fleet. This way, the tankers would need about 3 weeks to rejoin the Cruisers (that, assuming there's refueling possibility at target system will not need them), but only 2 Tankers are needed for the whole CruDron.

This makes the Tankers more a "starting jump" tool, but they can be quite useful, you'd need less of them, and they will not be siked in the battle.

Alternatiely, if the crossing of the gap can be prepared with time, the tnakers can ser a rfuelling point at J2, and so not having to return and leave the CruDron unsupportd for a while.

Sure, drop tanks may be quite useful, but you need them there in advance, and I guess not every system have them (maybe every Naval Base, though).

 

[AnotherDilbert]

Dilbert, I agree that they aren't going to do multiples of range increase like tankers to jets do, but I highly disagree that they are worthless for the purposes I am mentioning.

OK, not worthless, just very expensive.

Surprise of not showing up around ANY refueling point in the first 4 parsecs, increase of effective expedition/raid start points of J-8 ...

We just agreed tankers can't do J-8, more like J-5 or J-6?

speed of refuel getting hours if not days ahead of any pursuit/reaction, these are priceless capabilities.

Tankers refuel as fast as streamlined warships. Unstreamlined ships relying on tankers are slower.

Then once this sort of operation is known to an enemy, you can start employing misdirection with tanker fleets that operate in a system and are spotted, but are not actually supporting a fleet and jumps back/ahead with the 'extra fuel' onboard.

Quite, tankers adds flexibility, but at a cost. I would not halve my cruiser fleet to add a little flexibility...

You use tankers when you absolutely have to.

Re: drop tanks, seems a waste of shipyard tonnage to me, but could allow more conventional mercantile/support ships to act as ersatz tankers and help strap on the tanks. ...

Or they could be dropped off at a secret fuel dump for attachment at leisure to perhaps get the raider fleet back across the line once the responding hunters are closing in.

Depending on rules set, drop tank cost is trivial, so can't take all that much shipyard capacity.

Agreed, interstellar fuel dumps are great. They can be done with drop tanks and they can be made years in advance, especially by the defender. They can even be made by the warships themselves, without any need for tankers.

 

[AnotherDilbert]

I'll use the tankers in a different way than you tell in your example...

If I have the fleet performing a J2 first, eahc cruiser will still have 10 KDt (and so only needs 10 KDt more to reach destination), ...

Quite, but that would leave the raiders stranded on the other side of the rift, or lock the raiders in place for a month waiting for the tankers.

Alternatiely, if the crossing of the gap can be prepared with time, the tnakers can ser a rfuelling point at J2, and so not having to return and leave the CruDron unsupportd for a while.

Quite, but the warships themselves can build a fuel dump (using drop tanks), without any need for tankers.

Sure, drop tanks may be quite useful, but you need them there in advance, and I guess not every system have them (maybe every Naval Base, though).

They need to be built, so presumably need a shipyard. They have no TL in CT at least, so can be made in many places.

 

[McPerth]

Quite, but that would leave the raiders stranded on the other side of the rift, or lock the raiders in place for a month waiting for the tankers.

As much as any jump to hostile territory without tankers... Most cruisers have refuelling capacity by themselves.

I guess this is a matter of doctrine, resources at hand and situation (e,g, it's quite different if you're planing a quick advance, let's say Blitzkrieg style, or to send defensive reinforcements, let's say interior maneuvers style).

Quite, but the warships themselves can build a fuel dump (using drop tanks), without any need for tankers.

Warshipa with J4 capacity cannot build a fuel dump at J2 unless they have some significant cargo space, as they will need all their fuel to jump the round trip.

They need to be built, so presumably need a shipyard. They have no TL in CT at least, so can be made in many places.

And what kind of starport do you need to build them (I guess at lest C, as D-E starporrts have no yards, not even for repairs)? how long will it take?

AFAIK, none of those questions in answered in canon, as the drop tanks, aside from being told to exist, are poorly explained in most senses...

 

[mike wightman]

There is the fluff in the early JTAS News bulletins and the inclusion of TL requirements for the capacitors that make drop tanks viable as TL12 in HG79.

 

[kilemall]

Quite, but that would leave the raiders stranded on the other side of the rift, or lock the raiders in place for a month waiting for the tankers.

That's specifically rift as astrographic barrier operations, I am thinking more like conventional subsector density and refueling points, but doubling the systems that have to be patrolled/reacted to.



The raiders would indeed be 'cut loose' once behind the lines to refuel on their own and have to get back, possibly by executing their depredations and reaching a separate tanker fleet a subsector away.



The most profitable way to operate a raider fleet is for it to rampage for several weeks/several systems preferably doing real economic/political damage, force a response to thin out the defenses and/or reserves, then hit with the conventional force at a conventionally ranged target.

Quite, but the warships themselves can build a fuel dump (using drop tanks), without any need for tankers.

Horrible misuse of combat power potential vs. logistical power.

 

[AnotherDilbert]

There is the fluff in the early JTAS News bulletins and the inclusion of TL requirements for the capacitors that make drop tanks viable as TL12 in HG79.

As long as the ship is TL-12+ and prepared for drop tanks, there is no problem?

The drop tanks themselves have no TL limit.

 

[AnotherDilbert]

As much as any jump to hostile territory without tankers... Most cruisers have refuelling capacity by themselves.

If we cross a 6 Pc rift into enemy territory we are permanently stuck on the other side of the rift, unless we bring the tankers. Otherwise we don't need the tankers?

Warshipa with J4 capacity cannot build a fuel dump at J2 unless they have some significant cargo space, as they will need all their fuel to jump the round trip.

Use drop tanks. A 50 kDt J-4 warship with a large drop tank is a 100 kDt J-2 ship with 70 kDt fuel. Drop a 10 kDt tank, jump 2 Pc to the fuel dump, release the 50 kDt tank to the depot, jump back on internal fuel.

And what kind of starport do you need to build them (I guess at lest C, as D-E starporrts have no yards, not even for repairs)? how long will it take?

AFAIK, none of those questions in answered in canon, as the drop tanks, aside from being told to exist, are poorly explained in most senses...

I would guess B+ since we presumably a yard need manufacturing capacity, not just any port.

Building time is 10weeks; installation time is only a few minutes.

 

[kilemall]

OK, not worthless, just very expensive.

Not that much more expensive, the tankers don't need high end computers or weapons/screens or the high-end power plants to power same.

Also, what is the cost of fleets that glower at each other across a lethal border without achieving anything because it is too Jutland to risk their destruction in high value battles, or worse the conclusion tried and the fleets lost with no result?

The most expensive war is the one that is lost for lack of appropriate decisions within the ability of the star nation to have done. Putting the enemy on the horns of a dilemma is a proven way to break strategic logjams.

We just agreed tankers can't do J-8, more like J-5 or J-6?

The J-8 figure is more how far out the raider fleet can go with the tanker fleet boost/assist. The tanker fleet will need to refuel and get home, the first indication to the defenders of what breach where. Which in most cases is what you want, to create that allocation of resources.

Tankers refuel as fast as streamlined warships. Unstreamlined ships relying on tankers are slower.

I am referring to operational speed. Hooking up the hoses and pumping is going to be faster then maneuvering into a gravity well to make the fuel run or runs, then refine it. Not to mention managing the time, safety and surprise factors avoiding the 'friction' of even light patrol forces.

Quite, tankers adds flexibility, but at a cost. I would not halve my cruiser fleet to add a little flexibility...

You wouldn't have 1 cruiser:1 tanker ratios, but design the raiding fleet with enough to break through/crush most any casual patrolling group and do damage to mercantile/industrial targets while maintaining J-4 to maximize strategic speed. Breaking major planetary defenses is likely out of the question, so it's going to be a significant force but not planetary siege level, more breaking orbital/system facilities. Certainly not some budget busting exercise in cutting fleet combat power in half.

You use tankers when you absolutely have to.

A lot depends on the astrographics and relative fleet strength/dispositions and which side time is working for, but the tanker option is likely to apply in more situations then say rifts.

Agreed, interstellar fuel dumps are great. They can be done with drop tanks and they can be made years in advance, especially by the defender. They can even be made by the warships themselves, without any need for tankers.

Being mean and all, I would tend to have expiration dates on dumps, as space is big but not empty. If in-system, definitely risk of a small percentage of tanks being holed/hit with stellar flares/leakage per month.

Fuel systems are like any other ship system that requires maintenance, so figure a significant increase in failure once they have been a year plus deployed forward.

 

[AnotherDilbert]

That's specifically rift as astrographic barrier operations, I am thinking more like conventional subsector density and refueling points, but doubling the systems that have to be patrolled/reacted to.

There is no way to patrol every single gas giant in force. Since gas giants are generally so distant by M-drive they are basically their own systems. Hence you can nearly always find a GG to refuel from at standard density.

The raiders would indeed be 'cut loose' once behind the lines to refuel on their own and have to get back, possibly by executing their depredations and reaching a separate tanker fleet a subsector away.

A fuel dump solves the return, without trying to coördinate separate fleets months apart.

Horrible misuse of combat power potential vs. logistical power.

A cruiser is not all that more expensive than a tanker. I would rather have three cruisers than two cruisers and a tanker.

The cruisers can build up fuel depots in peace-time, not wasting any combat power.

 

[McPerth]

If we cross a 6 Pc rift into enemy territory we are permanently stuck on the other side of the rift, unless we bring the tankers. Otherwise we don't need the tankers?

That's why I said it would depend on situation. THe tankers will join you in 3-4 weeks , and if you use drop tanks th esituation is more or less hte same...

Also, this 6pc gap may be the fastes, but not the only, way in/out...

Use drop tanks. A 50 kDt J-4 warship with a large drop tank is a 100 kDt J-2 ship with 70 kDt fuel. Drop a 10 kDt tank, jump 2 Pc to the fuel dump, release the 50 kDt tank to the depot, jump back on internal fuel.

That woul dtake longer than just using drop tanks or tankers, and be quite more expensive...

I would guess B+ since we presumably a yard need manufacturing capacity, not just any port.

According some sources (e.g. Hard times) C starports have limited building capacity too...

 

[mike wightman]

As long as the ship is TL-12+ and prepared for drop tanks, there is no problem?

The drop tanks themselves have no TL limit.

Without the capacitor tech the drop tanks are just additional fuel carried externally - their fuel can not be used without transferring it to the jump fuel tanks.

But yes, the tanks are just tanks, manufacturable at any A or B port regardless of TL I would say.

 

[mike wightman]

Use collectors to power the tanker's jump drive...

 

[AnotherDilbert]

That's why Isaid it would depend on situation. THe tankers will join you in 3-4 weeks , and if you use drop tanks th esituation is more or less hte same...

Also, this 6pc gap may be the fastes, but not the only, way in/out...

Jumping in directly with drop tanks would not allow you a way to retreat. Since you basically need to return to a shipyard to repair at least the spinal after every battle, that is a bit dangerous, bordering on suicide mission.

That woul dtake longer than just using drop tanks or tankers, and be quite more expensive...

Agreed, it would take longer, but can be done long in advance, as we plan the campaign.

It would save us the need for tankers, so would save a lot of money for more cruisers...

 

[McPerth]

Use collectors to power the tanker's jump drive...

What do you mean? without fuel?

 

[AnotherDilbert]

Use collectors to power the tanker's jump drive...

If we have access to Collectors, why would we need tankers?

 

[mike wightman]

Something I have wondered since MgT and T5 changed the way collectors work.

The original Annic Nova version required 1-6 weeks depending on star type and distance from the star to recharge.

The version that is used in MgT Great Rift - which is detailed in MgT HG2e - can recharge even in an empty hex.

The only disadvantage appears to be charging time - if you need to break off by jumping you want a fusion or antimatter powered jump drive.

I could see ships with 'duel fuel' jump drives - a collector powered drive for strategic movement and a hydrogen fuel powered drive for combat circumstances.

If I were the Zhodani planning the FFW I would have ordered the production of many collector based fleet tenders to move my invasion fleets through empty hexes to jumping off points in systems close to important Imperial targets.