All Warships Should Have Drop Tanks

[far-trader]

Somewhere there is a misjump roll DM for using Drop Tanks. That implies that you can't clear the 100D of the tanks before the jump, meaning it has to happen pdq after sucking down the fuel. Pretty sure I didn't just make it up

I recall that, too, but not where. Wait... I found it...

MGT. Interesting. But not where I got it from. Been playing it that way for ages. From CT (a supplement or game or digest maybe) I seem to recall but I could be mistaken. I thought it was built into the rules by MT, but again, maybe not. Maybe it was just a house rule.

It is looking to fall into the mystery realm shared by my recollection of an early rule about just how long you can wait before jumping or aborting (or exploding) after using the fuel. Another one of those instances where I was sure the rule was official and dating back to CT, but have been unable to find it and am leaning to we must have houseruled it so long ago that I've forgotten the fact and attributed it to canon. Though I'm still not 100% convinced on either of the two not being canon somewhere

 

[rancke]

Mongoose adds machinery to the cost of drop tanks...

A drop tank mount costs MCr1 per 50 tons of fuel in the drop tank, and takes up two tons of space per 50 tons of fuel for the fittings to transfer fuel.

A drop tank itself costs MCr 0.1 per 50 tons of fuel space.​

This makes drops tanks slightly less advantageous. This is definitely a retcon, but one that I don't mind at all. Anything that can explain why they're not used more in civilian traffic (without making it unlikely that they'd be used at all) is fine by me, since that's what canon tells us: They exist, but they're not in general use in the Marches.

Jumping using a drop tank applies a –(15–TL) DM to the roll for misjumping (see page 141 in the core rulebook).​

So at TL 15 they don't add to the risk at all?

When a drop tank is used, roll 2d6. On an 8+, the tank survives the
ejection process and can be retrieved and reused. Otherwise, it is
destroyed by the expanding jump bubble or warped by the jettison
explosion. At TL14 the use of drop tanks has been improved to such
a degree that drop tanks designed at this tech level or above will
automatically survive use.
(MGT-HG p.43-44)​

Note that the mounting goes on the ship.

Reducing the savings in interior space a tiny amount. Doesn't hurt, but doesn't really help much. Except with the verisimilitude.


Hans

 

[Selandia]

back to jump tankers

The use of jump tanker

No, it's not doable in canon.

you've maybe got a few minutes, definitely less than 20, to suck the fuel out for jump. Presuming multiple fueling ports, large bore, and backfilling while drawing the main fuel off, it's pretty tight...

With a tanker, if it's larger than you, you're in it's 100 diameter limit, or close to it, and have to disconnect and clear the connections (rather than simply ejecting tanks) before you can get to that point. And if not clear, you go "BOOM!" .

I understand that filling tanks under the common refuelling procedure after the capacitors have been charged is a problem. But if tanks A can be drained out at speed X for charging the capacitors you should be able to drain the tank B into the adjacent tank A at speed X given the same purpose built material. Using quick release connectors allow tank B to be "dropped" (actually speed away under its own power if a jump tanker) like L-Hyd tanks.

In MTU, the idea is to give Jn-2 to a 1,000 Jump tug using Z drive (book2, 81)that have a 500 t intrinsic jump fuel tankage (Jn-1) and a 4,000 payload. The 600 t jump tankers backfill 500 t of fuel as the intrinsic 500 t get burned. Even if the backfiling is a bit slower (it can't be faster), there will be near 500 t poured and available after the initial 500 t would be used. While the power plant keep burning fuel to reach Jn-2 capability, the jump tanker (note that there is a special design of jump tanker adapted to the Jump-tug) will have time to pour the last few tons and speed away. Note that a 500 t fuel pod acting as a dismountable tank ( with 3,500 t cargo) would not pose a problem.

It is a 'Kangaroo operation" for a liner service. The jump tanker sit where an additionnal fuel pod acting as a dismountable tanks would fit, and the assembly is purpose built. In fact, the jump tanker can ride the tug through the jump as any rider or cargo pod could do, acting as a fuel pod/dismountable tanks. Unlike a fuel pod, it could launch and act as a tanker skiming gaz giant to refill the main tanks before doing another run to refill itself. It is not common in the Marches for it is a costly system. However, in liner operation, with a tug departing every 4 days from A to B and back, you need only a jump tanker at each ends to assist. Only 2 jump tanker rather than 4 fuel pods as capital expenses and 500 t of cargo a jump as extra revenu.

It would be exceptionnal for such service to be available to players' ACS in the Marches if only because couplings and transfer systems require an unlikely harmony outside a major organisation.

Selandia

 

[Selandia]

As to why disposable tanks are not more used commercially:

A)
the rules do not need to state that there is no such things as a free lunch, the referee is there for common sense to be applied:

The referee must impose fitting cost and wasted time at shipyard,

They are not available unless spaceport B is available for they need shipbuilding capability fo be fabricated.

If hauled from a neighbooring systems to a C starport = add shipping cost

You know before jumping that there is a type B starport in that system? But they may not have in stock the tanks for your type of ship. Pay up front and come back in D weeks if they can be built locally.

When will the yard have the time to fit them if and when they will have them?

Are local reg about obital garbage forcing the payment of a recovery fee?

Collapsible tanks are an alternative to drop tanks in some case.

To avoid catastrophic missed release, Jump Tankers will work only with the host ships they have been design to operate with

The cumulative effect of cost, delay, uncetain and limited availability will make them prohibitive in free trade, aggravating availability issue.

B)

The economic of CT and some later variant is extremely crude, intended to allow "Pay As You Go Adventuring" rather than "Adventure in Accurate Accounting" and hardly more. The small scale operation depicted in free trade are making sense for the travel of Earl Dumarest and Adventure class ships or Marco Polo and is very fine with me.

However a lot of things that would make business sense (such as the use of riders in commercial operations) are not done in CT. GURP is doing better to make sense of free trading by presenting it as living from the leftovers of the Megacorp business and any Merchant Lord game usually deal with operation out of proportion to CT free trade. So at one point, the ref have to balance some things out for adventure to make sense.

Selandia

never written Trillion Credit Business.

 

[rancke]

...the rules do not need to state that there is no such things as a free lunch, the referee is there for common sense to be applied:

Not IMO. The rules are supposed to help the referee apply common sense, not to rely on him to plug holes. Just because a good referee can fix bad rules is no excuse for bad rules.

The referee must impose fitting cost and wasted time at shipyard,

Negligible compared to a 40 years service life. And should be taken into account by the rules for shipping costs. It's not really the referee's job to do in-depth analysises of shipping costs (though some of us do it anyway ).

They are not available unless spaceport B is available for they need shipbuilding capability fo be fabricated.

If hauled from a neighbooring systems to a C starport = add shipping cost.

Which is probably worth it. You save a LOT in the per unit cost of high-performance jumps. For jump-6, for example, you have a realisitc payload of around 15% (or 13 or 17 -- I've forgotten the exact figure, but it is in the teens). If you remove 60% internal tankage, you quintuple the capacity of the vessel at a comparatively trivial cost.

Of course, you need to be able to sell the extra capacity.

You know before jumping that there is a type B starport in that system? But they may not have in stock the tanks for your type of ship. Pay up front and come back in D weeks if they can be built locally.

Of course I know. I'm running an interstellar passenger line or freight company. I'm not going to invest in a ship unless I'm confident that I can fill its capacity regularly for the next 40 years[*]. To maximize my profits, I need to have the best turnaround I can achieve, so I've made a deal with the shipyard to be ready to fit me with new drop tanks as soon as I appear in the system. With heavy penalties for non-performance and possibly insurance too.

[*] I might turn out to be wrong, but that's doesn't mean I wasn't confident.​

When will the yard have the time to fit them if and when they will have them?

See above. Interstellar transport is serious business. This is the framework that free traders operate in the cracks of.

Are local reg about obital garbage forcing the payment of a recovery fee?

Almost certainly. Cost is a couple of tugs and operating expenses for same, spread out across scores of vessels.

Collapsible tanks are an alternative to drop tanks in some case.

No, they're not. They're used in completely different cases.

To avoid catastrophic missed release, Jump Tankers will work only with the host ships they have been design to operate with.

I should hope so!

The cumulative effect of cost, delay, uncetain and limited availability will make them prohibitive in free trade, aggravating availability issue.

Free traders aren't the problem in themselves. The problem is that the competition, the regular companies, can offer to move passengers and cargo six parsecs for less than free traders have to charge for a two-parsec jump (Guesstimate).

The economic of CT and some later variant is extremely crude, intended to allow "Pay As You Go Adventuring" rather than "Adventure in Accurate Accounting" and hardly more. The small scale operation depicted in free trade are making sense for the travel of Earl Dumarest and Adventure class ships or Marco Polo and is very fine with me.

This is true. These slightly less inaccurate economics we talk about here are for universe-building, not adventure-running.

However a lot of things that would make business sense (such as the use of riders in commercial operations) are not done in CT.

Which means there's a disconnect between "reality" and the rules. And that's what some of us like to discuss.

GURP is doing better to make sense of free trading by presenting it as living from the leftovers of the Megacorp business and any Merchant Lord game usually deal with operation out of proportion to CT free trade. So at one point, the ref have to balance some things out for adventure to make sense.

Or not run Trading Game campaigns.


Hans

 

[Selandia]

Not IMO. The rules are supposed to help the referee apply common sense, not to rely on him to plug holes. Just because a good referee can fix bad rules is no excuse for bad rules.

true in theory, but that may result in 300 pages rulebook. I does not mind short rules and long wisdom.

Negligible compared to a 40 years service life. And should be taken into account by the rules for shipping costs. It's not really the referee's job to do in-depth analysises of shipping costs (though some of us do it anyway ).

Mostly true. The referee is indeed implicitly told not to bother with the macro economic of shipping and he may be rightly satisfied to consider it negligible. From the moment that rules state cost of purchase per tons, it is considered not negligible. Still a fellow traveller decided to go in dept and ask why the traveller universe could make sense. So the ones amongst us that go AAA write more in this tread . If we go AAA: as a recurent operating cost, more than tripling your fuel cost (500 cr a ton of fuel + 1,000 cr a ton of tank + fixed 10,000cr a tank ) is significant. Jump tug with cargo lighter find their advantage in jumping once every 8 days because they use their costly jump drive 87.5% of the time, rather than 50 % of the time like a standard ship running to the planets and performing 2 jumps a month. Having to go to the planet to have L-Hyd tanks fitted would negate the advantage of jump tug. turn around time is not negligible. Jump tanker on the other hand may dock with host ship as a normal docking operation without yard assistance.

Which is probably worth it. You save a LOT in the per unit cost of high-performance jumps. For jump-6, for example, you have a realisitc payload of around 15% (or 13 or 17 -- I've forgotten the exact figure, but it is in the teens). If you remove 60% internal tankage, you quintuple the capacity of the vessel at a comparatively trivial cost.

Very true, that is why I use jump tanker.

Of course, you need to be able to sell the extra capacity.

And that is hard on the table given in CT, intended for free trade. Note that this is the reason why I initially use the less expensives dismountable tanks or fuel pods. When you reach a point, you go to L-Hyd tanks or jump tankers.

Of course I know. I'm running an interstellar passenger line or freight company. I'm not going to invest in a ship unless I'm confident that I can fill its capacity regularly for the next 40 years[*]. To maximize my profits, I need to have the best turnaround I can achieve, so I've made a deal with the shipyard to be ready to fit me with new drop tanks as soon as I appear in the system. With heavy penalties for non-performance and possibly insurance too.

[*] I might turn out to be wrong, but that's doesn't mean I wasn't confident.​

.

Absolutely right, but you are now operating like my ZEN Starline Group(created to release the players from the burden of ship management), not like the free trader of CT. By the way, at the game of Trillion Credit Business, Jump tankers beat L-Hyd. What I said was intended to apply to Free Trader.

See above. Interstellar transport is serious business. This is the framework that free traders operate in the cracks of.

See above

Almost certainly. Cost is a couple of tugs and operating expenses for same, spread out across scores of vessels.

Agree, meaningless by itself, part of the cumulative effect.

No, they're not. They're used in completely different cases.

In some case that make it mandatory to have additionnal fuel, (for a J-1 trader that would have to move itself across a J-2 space without fuelling point) you may use drop or collapsible (if cargo space avail).

I should hope so!

me too

Free traders aren't the problem in themselves. The problem is that the competition, the regular companies, can offer to move passengers and cargo six parsecs for less than free traders have to charge for a two-parsec jump (Guesstimate).

Very Small Scale Tramping ( a.k.a. Free trading in CT) is the problem of this issue, because unlike liner companies FTrader could not leverage themselves to a structural role (shipyard maintenance deals, building deals, guaranteed monthly shipment etc...) in a world's shipping business. The fact that a ZEN Starlines may have a set of L-Hyd build/refilled/fitted for it every 4 day does not mean that a free trader could have custom build tanks tomorrow. In fact, any tramp will be pushed way back after ZEN or any other starline.

This is true. These slightly less inaccurate economics we talk about here are for universe-building, not adventure-running.

glad we agree

Which means there's a disconnect between "reality" and the rules. And that's what some of us like to discuss.

love to discuss

Or not run Trading Game campaigns.

Hans

Amen

 

[Theophilus]

Great discussion, keep going.

First off, I see we are using several rulesets. Mongoose, which I don't have, has different rules than T4, which I don't have.

I wonder if some of the rules we "remember" may come from sources like DGP's "Starship Operator's Manual" or other sources such as alternate rules from magazines etc.

For instance, Jumping from a planetary docking bay is not forbidden, SOM pg 13, and you wont necessarily go "boom".

But, back to subject. The "expanding jump bubble destroys drop tanks" rule sounds like an explanation why all "megamerchant" ships don't use drop tanks. It actually violates the rule previously mentioned that drop tanks weren't invented til 1080 (TL14), since it allows drop tanks at a TL lower than 14.

Still, the million ton bulk carrier with J4 drives uses 400,000 tons of space for fuel, where as using drop tanks for fuel and adding 400,000 tons of cargo space would only make sense.

CT Book 5, High Guard, Page 27:

"Disposable fuel tanks may be added to the ship to increase its range.

...the result is more interior space available for cargo and passengers."

Implies to me that one must have the some range capability on board. If you look at the only(?) canon example that fits:

I think you mixed your metaphor's, as they say. Disposable tanks do not increase they ships range, they just provide the fuel for the jump. I assume your saying the above mentioned megamerchant has J1 fuel on board and J3 fuel in it's drop tanks.

 

[rancke]

But, back to subject. The "expanding jump bubble destroys drop tanks" rule sounds like an explanation why all "megamerchant" ships don't use drop tanks. It actually violates the rule previously mentioned that drop tanks weren't invented til 1080 (TL14), since it allows drop tanks at a TL lower than 14.

The Imperium had been TL15 for three generations in 1080, so drop tanks would be TL15 if your argument held water. But it doesn't. Just because something is possible to make at a particular tech level doesn't mean that it will necessarily be invented at that TL. (In some cases it can't be invented at the lower TL; example, the germ theory of disease requires microscopes to discover but can be applied as soon as you can boil water). In this particular case, the capacitors in question can be made at TL9 but wasn't invented until late 11th Century Imperial.


Hans

 

[far-trader]

For what little it's worth the first publication of Drop Tanks in HG1 framed it as TL12 being the required TL for the high capacitor accumulator (MCr 0.5 no tonnage listed). The price for the tanks were the same but they were absolutely one time use only and not carried through jump. They were just to be used to jump, not to be jumped with.

 

[fredofmars]

<snip>I see we are using several rulesets. </snip>

Another thing to consider (at least in the TNE rule set) is surface area. If you don't have enough surface area to mount the tanks, then you couldn't use them anyway.

 

[Selandia]

Another thing to consider (at least in the TNE rule set) is surface area. If you don't have enough surface area to mount the tanks, then you couldn't use them anyway.

You could add the position of connectors and the issue of streamlining. Finding the right type for your ship if wandering freely through the star onboard a oddball design is a challenge. Of course, purpose built liner are not having this as a problem.

Whatever set of rule you use, drop tanks are confronted to design limitations intended to preserve the original flavor of the game when it comes to wandering on your own ship: Adventure Class Ship work hard to scrape a living.

Selandia

 

[Theophilus]

The Imperium had been TL15 for three generations in 1080, so drop tanks would be TL15 if your argument held water. But it doesn't. Just because something is possible to make at a particular tech level doesn't mean that it will necessarily be invented at that TL. (In some cases it can't be invented at the lower TL; example, the germ theory of disease requires microscopes to discover but can be applied as soon as you can boil water). In this particular case, the capacitors in question can be made at TL9 but wasn't invented until late 11th Century Imperial.


Hans

How's that?, During the Third Interstellar War and the War of Solomani Liberation (990-1002) the Imperium was at TL14. Some experimental equipmemt was entering service at TL15, But the Imperial Fleet was TL14. Unless there was a massive replacement of equipment in a 72 year period, most of the Fleet was still TL14.
The last Atlantic class cruiser was built 1050. The Last Azhanti was built in 1005. They were declared obsolete in 1048. How do you figure three generations in 1080?

The Kokirraks were brand spanking new TL14 ships in 990, by 1107 they had been upgraded to TL15, and were obsolete but still the backbone of the Marches navy.

Now, the Plankwell class, being new TL15 ships, of a modular design, would probably benefit from drop tanks. Since their J4 drives fuel tankage is greater than the Tankage of the J3 Kokirraks. Why someone didn't think to use drop tanks is a mystery. Probably because no one had done to before.

So my arguement is: Some naval designer has a Duh, moment and say's "why don't we use drop tanks?"
There available.
They provide strategic advantages.
They influence tactical choices. (Do I fight, or do I run since I have fuel)
They provide alternate fuel for those pesky shattered fuel tanks, allowing movement of damaged ships out of the war zone.
They provide multiple advantages in commercial usage. More cargo equals more profit.

Duh, why aren't we using drop tanks?

 

[Selandia]

innovation

If one take human history as base, one must consider that the military is a mixture of innovators and conservatives, with the older conservative usually in charge. Often, they are not conservative because they are old, but because through extended service (and that make them old and in charge) they have mastered the problem as routinely formulated and are unwilling to introduce a new variable that increase the " fog of war". "Don't fix something that is not broken...why change a winning formula...why introduce a weapon that will make our fleet obsolescent... are expression of conservative "wisdom" that may win arguments until a war put ideas to the test, and sometime proves that the inovator wrong.

Few examples in a much much longer list that may include better exsmples:

Since when could we have built the Ironclad? Why did the USN had to wait for the Merrimac to figure that wooden ship should not have been there.

Shallow run torpedo and Pearl harbor anyone?

Fisher and its fight for the Dreadnought?

The introduction of Oil fired boiler for the fleet vs availability of oil ?

The Surface-surface missile vs 1967 sinking of the Eilath?

Nelson daring to "torch the book" and scrap the "line of battle" at Trafalgar?

On the other hand, the inovators sometime got the wrong idea.

Nearly all Imp Japan Army fighter (not IJN Zeke) using nothing more than twin 7.7mm Mg in 1941 (or italian using a pair of 12.7) because it was doctrine that light weight and agility was everything?

Skua and Fulmar (RNAS insisting on biplace fighter to be used as recon plane)?

Single engine light bombers that pretend to be fast enough to operate without fighter cover?

Battle cruiser at Jutland?

Or they have the wrong timing, like "la jeune école" of the French navy around 1900 that was 15-35 years ahead of the relevant technology.

It would have taken nothing more than a single catastrophic incident at the R & D stage to have convinced even the less conservative that things were not ready.

Changing doctrines and technology on such a massive scale as the Imperial fleet is quite a ressources consuming gamble and it may be the only excuse needed (if one is needed) to justify some parts of the canon.

Conservatives are not always wrong to be prudent, in the drop tanks case, the HG rules make them wrong, but lets pretend the NPC did not knew the rules and were afraid of the rolls.

Selandia

 

[rancke]

How's that?

Rounding. I usually count 30 year to a generation. 80 years ~ 3 generations.

During the Third Interstellar War and the War of Solomani Liberation (990-1002) the Imperium was at TL14. Some experimental equipmemt was entering service at TL15, But the Imperial Fleet was TL14. Unless there was a massive replacement of equipment in a 72 year period, most of the Fleet was still TL14.

The Imperium is said to have achieved TL 13 in 300, TL 14 in 700, and TL15 in 1000 [RfC:34]. Considering the unlikelihood that someone just happened to invent the first device of each tech level in years divisible by 100, I interpret that to mean that these are dates that historians decide on after the fact, and that they mean that a significant number of Imperial worlds had achieved the indicated tech level by those dates.

How many are "a significant number"? I don't know, but since the Imperium by 1117 has a goodly sprinkling of worlds that are listed as TL16, yet isn't considered to be TL16, I would say that it could be as low as, say, 1% (As long as those are pop 8+ worlds).

The last Atlantic class cruiser was built 1050. The Last Azhanti was built in 1005. They were declared obsolete in 1048. How do you figure three generations in 1080?

The Imperium is still building TL 10-14 ships in 1105: "The Imperial Navy procures ships at TL 10 to 15." [HG]

Why? No canonical explanation, but my take is that the Imperium tends to take its membership taxes in goods produced on the member world. If Mora was TL 14 in 1030, it would be building TL 14 ships for the Imperial Navy. Once it reached TL 15, it would start building TL 15 ships for it. Nowadays TL 10-14 worlds don't pay their taxes in front-line battleships, but they still build tankers and transports and less-than-jump-6 couriers.

The Kokirraks were brand spanking new TL14 ships in 990, by 1107 they had been upgraded to TL15, and were obsolete but still the backbone of the Marches navy.

What is the source of this information about the Kokirraks? That they were first built in 990 and that they were TL14 at the time? From the information that I can find (p. 42 of FS), I'd be much more inclined to believe them to be brand spanking new TL15 ships in 990.

Now, the Plankwell class, being new TL15 ships, of a modular design, would probably benefit from drop tanks. Since their J4 drives fuel tankage is greater than the Tankage of the J3 Kokirraks. Why someone didn't think to use drop tanks is a mystery. Probably because no one had done to before.

<<Sigh>>. I get it. This is from an MGT source, isn't it? Because according to FS, Kokirraks are jump-4. I'm sorry to impose upon you, but could you please include quotes of the historical evidence you rely on, as I don't have MGT:High Guard? Otherwise we're simply arguing past each other.

(FYI, my references are: FS = Supplement 9, Fighting Ships; HG = CT:High Guard; RfC = Referee's Companion.)

Anyway, Plankwells are hardly new TL15 ships.

"For decades, the Imperial Fleet in the Spinward Marches has included at least one BatRon of Plankwell class ships, but recently (1102), the last such squadron was rotated to the strategic reserve in Corridor Sector." [FS:40]​

If "for decades" indicate any span of time longer than 20 years, the Plankwell class was designed before drop tanks were invented. The bit about being rotated back into the strategic reserve might even indicate that they're getting a bit long in the tooth, which would make the design at least 40 years old.

So my arguement is: Some naval designer has a Duh, moment and say's "why don't we use drop tanks?"
They're available.
They provide strategic advantages.
They influence tactical choices. (Do I fight, or do I run since I have fuel)
They provide alternate fuel for those pesky shattered fuel tanks, allowing movement of damaged ships out of the war zone.
They provide multiple advantages in commercial usage. More cargo equals more profit.

Duh, why aren't we using drop tanks?

Cut and paste time.

* Drop tanks cost money to buy and money to replace.

* Spare drop tanks requires big freighters to move about, so they represent an additional logistic problem.

* Ship procurement on the scale the Imperial Navy operates on is planned many years ahead (The Adamdun was finished in 247-1089, 15 years after the Shulgi was laid down, thus planned more than 15 years before it was finished. And that's just a small 1200T ship. [TK:10]) Dreadnaughts take several years to build, funding to build them are authorized before that, plans to build them are worked out long before that.

* The Imperial Navy may want to test the concept before going ahead and spending trillions on new battleships that might turn out not to work as expected. Maybe try them out on smaller designs first. And perhaps build a couple of squadrons worth each of few different cruiser and battleship designs.

* "And, you know, if we allow the Navy to have drop tanks, they'll just use them even when they're not needed, and that costs money. Better not. We've managed fine without drop tanks for a thousand years and more. These newfangled ideas are never as good in reality as they look on paper." [Count Damien Tancredi, Imperial Minister of Finance, 1090][*]

[*] NB! Not canonical.​

Hans

 

[Theophilus]

What is the source of this information about the Kokirraks? That they were first built in 990 and that they were TL14 at the time? From the information that I can find (p. 42 of FS), I'd be much more inclined to believe them to be brand spanking new TL15 ships in 990.


<<Sigh>>. I get it. This is from an MGT source, isn't it? Because according to FS, Kokirraks are jump-4. I'm sorry to impose upon you, but could you please include quotes of the historical evidence you rely on, as I don't have MGT:High Guard? Otherwise we're simply arguing past each other.

No, This is from CT Supp 9 Pg 42.
BB-S436J4-C78909-697T9-0 The 3 is Jump Drive
Fuel 80,000. 60,000 for J-3, 20,000 for PN

The written text says:
Performance: Jump-4, 6-G, Power plant-A. This is a misprint as you cannot get a J-4 6G drive in a Kokirraks Hull. Doing so takes 87% of the ship for Armor Bridge, Drives and Fuel. Leaving to little room for the weapons and crew.

Therefore the written text Jump-4 must be a misprint.
(Please note the same misprint for the Tigress class DN; 190,00 tons fuel, Needs 240,000 tons for J-4)

As to the Kokirraks being in service in 990, T20 Gateway to destiny places a squadron on Kokirraks at the Ley sector capital in 993.(Page93) Since TA7 Fighting ships places all Imp warships at TL14, that would Include the Kokirraks.

Please note that retrofitting the Kokirraks to TL 14 is not difficult, Meson reduced to Q, Power plant reduced to fit the available tonnage, etc. The text in Supp 9 says that the Kokirraks are one of the older ships in Imperial service and are now being phased out. Therefore having them in service 100 years ago, like the AHL and the Atlantic class (TL14 in TA7), and the Chrysanthemum, also over 100 years old, makes a kind of sense.

 

[rancke]

No, This is from CT Supp 9 Pg 42.
BB-S436J4-C78909-697T9-0 The 3 is Jump Drive
Fuel 80,000. 60,000 for J-3, 20,000 for PN

The written text says:
Performance: Jump-4, 6-G, Power plant-A. This is a misprint as you cannot get a J-4 6G drive in a Kokirraks Hull. Doing so takes 87% of the ship for Armor Bridge, Drives and Fuel. Leaving to little room for the weapons and crew.

Therefore the written text Jump-4 must be a misprint.

It certainly is a discrepancy. Thanks for clearing that up.

As to the Kokirraks being in service in 990, T20 Gateway to destiny places a squadron on Kokirraks at the Ley sector capital in 993.(Page93) Since TA7 Fighting ships places all Imp warships at TL14, that would Include the Kokirraks.

That's going to mess with a lot of intricate discussion some of us did a while back on the discovery date of Black Globes and (in that connection) construction dates for Kokirraks. >>Sigh<<

Maybe these are a different class of Kokirraks[*]? After all, all Imperial warships are TL14 at the time, and the present-day Kokirraks are TL15.

[*] The Kokkiraks? ​

Please note that retrofitting the Kokirraks to TL 14 is not difficult, Meson reduced to Q, Power plant reduced to fit the available tonnage, etc.

I assume you mean backdate (or whatever the proper word is) them to TL14. I think it is immensely difficult. Substituting a factor T for a factor Q is not a problem, except for the increased power energy point requirement. But the killer is the power plant. The minimum factor for the power plant is 6 (maneuver 6), but the minimum realistic one is 7 (actually, 6+; 1200 EP plus whatever the weapons, screens and computer need). That requires a power plant with a minimum size of 14% of the ship's tonnage. More if you want the proto-Kokirrak to have any sort of secondary energy armament.

I admit that it's just possible to imagine a TL14 design that has PP 6 by assuming that it didn't have enough agility to take full advantage of its maneuver drive and almost no secondary energy weapons. That way the power plant (12%) plus power plant fuel (6%) will take up a total of 18% of the ship tonnage. By installing a factor 10 TL15 power plant (10%) and partitioning off part of the cargo space to provide another 4% fuel tankage, you get a new combination that takes up 20%. You also get 2% of the old engine room that you can use for something new. Or you could put half the extra tankage in the engine room and the other half in the cargo space.

But is it a plausible upgrade? Not in my opinion. The thing to remember is that the original hull remains the same and upgrades don't affect the major interior partitions, and that retrofitting components is expensive. Replacing a factor Q with a factor T and accepting a lower agility might make sense; ripping out power plants is a different matter. Building a new TL15 design and retiring the TL14 design from front-line service makes the most sense.

The text in Supp 9 says that the Kokirraks are one of the older ships in Imperial service and are now being phased out. Therefore having them in service 100 years ago, like the AHL and the Atlantic class (TL14 in TA7), and the Chrysanthemum, also over 100 years old, makes a kind of sense.

The AHLs start getting phased out after about 60 years and the Atlantics may not have begun being built until 1020. The Chrysanthemum design goes back for over a century, but that doesn't mean that the first ones are still in action 100 years later. Just that they were still being built more recently than that.


Hans

 

[Starviking]

So my arguement is: Some naval designer has a Duh, moment and say's "why don't we use drop tanks?"
There available.
They provide strategic advantages.
They influence tactical choices. (Do I fight, or do I run since I have fuel)
They provide alternate fuel for those pesky shattered fuel tanks, allowing movement of damaged ships out of the war zone.
They provide multiple advantages in commercial usage. More cargo equals more profit.

Duh, why aren't we using drop tanks?

One thought that comes to mind is that losing the occasional Gazelle to a misjump is acceptable, but losing a Plankwell occasionally is not.

Also, it may be far easier to get the Drop Tanks from the ship to the ship's 100D limit before Jumping with a Gazelle rather than with a bigger ship. Math could be done on that, but I haven't got the time these days.

 

[whartung]

Ah, drop tanks.

Personally, I'm a "jump tanker" advocate. Some may remember my treatise several years ago laying out the "economics" using some FF&S designs. (Economics are in quotes since we know the values used were dreamed up over coffee in Illinois one day.)

But, at the same time, there is some credence to the canon argument of "Regardless of how viable it may or may not be, apparently it's Just Not Done, and we simply don't know all the facts as to why".

But we can still play along and try and analyze the problem anyway (which is why I like jump tankers for large commercial operations, the "numbers" are really nice).

The first question to be answered is how is Jump Fuel consumed. Apparently, it is consumed at some specific rate, and whatever rate that is can be met by a tank somehow bolted to a ship. That means the the fuel is not consume instantaneously, and that the fuel is not consumed "in flight", within jump space. Otherwise, drop tanks wouldn't be viable at all, as they could not be dropped before jump (as their fuel would be needed if its consumed during jump), and they likely could not meet the fuel rate of "instantaneous". Is there some assumption that it takes 3 times longer to charge for a J3 than it does for a J1, since it consumes 3 times as much fuel? It's a fair leap, I think.

So, given that drop tanks apparently DO exist, that implies that the jump drive consumes X Tons of fuel per minute during it's firing sequence.

The next question is: "When does jump happen?" That is, when the jump process starts to consume fuel, is that like lighting a fuse, or is the consumption process simply a matter of charging the jump capacitors and then the pilot has some window of time to "pull the trigger" after the capacitors have reached the appropriate charge. How big is that window? 0s? 10s? 1 hour? Can you overcharge the capacitors and let them leak to expand the window?

A better way to phrase this is "How long after the fuel is completely consumed for jump, does the pilot have to initiate the actual jump process?" Also, how late in the charging and jump process can the pilot abort it completely?

This is important because it can address the aspect of the drop tanks interfering with the jump itself.

I think there's this vision of drop tanks being like the tanks on jet aircraft. Visions of F-86s over Korea blasting tanks away as they dive in to combat.

That's not the role of these tanks. Drop tanks on aircraft give them long loiter times and can be jettisoned in case of combat. On starships, typically, the drop tanks are used before combat, prior to jump, where time is less of a concern.

So, the idea that the ship is triggering the jettison of the tank "just before jump" seems a bit far fetched to me. If the tanks proximity at time of jump is that dangerous (and a misjump is considered, effectively, lethal, IMHO), then you simply jettison the tanks early in the jump charge process so the tanks and the ship have adequate time to get out of harms way. You manage this by buffering the fuel necessary in internal ship tanks to handle the last moments of the charging cycle. You can also use this buffer to determine whether it's safe to jump at all, if, for instance, a tank did not jettison properly and would result in a misjump if it remained, then the pilot has the opportunity to abort the sequence. Internal tanks + post charge jump window is the amount of time you have available to ensure that the drop tanks will not interfere with the jump.

If the jump process is a lit fuse, that can't be stopped once started (that is, once we hit the GO button, fuel begins to be consumed at whatever rate and at the end, a jump (or misjump) happens no matter what), then it's easy to argue that drop tanks are simply too dangerous to use, save for military vessels. A stuck tank can easily result in a misjump. You can buy time with internal tankage, but a stuck tank is a stuck tank and is likely to not get unstuck within that buffer of time. Perhaps a risk worth taking for military operations, but likely not for civilian ones.

Perhaps the fuel rate is simply too fast for anything interesting to happen once the process is started. From GO button to Jump space is 60 seconds and in that time 60,000 tons of fuel is consumed for a J6, 100K ship. That's 3.7M Gallons per sec, or about 25 times what goes over Niagra Falls. So, I don't know how realistic that is. Those are some pretty big pumps and pipes.

So, really, much of it comes down what the jump process really is. If the fuel consumption rate is reasonable (measured in minutes, perhaps 10s of minutes), then however many minutes are necessary to get the tanks away from the ship to avoid a misjump can be accounted for with internal tanks (e.g. 20 minute charge cycle, 5 minutes using on board tankage, tanks are dropped at the 15m mark, and ship has 5m of acceleration to get away from the tanks, or a tanker...).

*I* think that there is a reasonable jump charge time, that there is also a jump window after charging, and that a jump can be aborted at anytime up to when you hit the post charge "GO" button. Combining those charge times with buffer tanks, and reliable connections make jump tankers, and drop tanks, a viable, safe option. I found them viable in TNE, which use FAR less jump fuel than HG. It's even more viable for the ships with the larger fuel requirements.

If anyone has documentation on the jump process and how it relates to this discussion, that would be welcome.

I'd have think more about the operational aspects of using drop tanks for military operations vs jump tankers for large, commercial cargo ships. I don't know how much sense drop tanks really make "in the wild".

 

[Spike]

Whartung has already addressed most of the points I would be making in this argument, only with more references to canon than I could possibly do.

I would like to state that it seems to me that a number of people are reading an awful lot into the description of drop tanks, specifically the bit about how they are 'one use only', or disposable, or however it says it (sorry, no book handy to reference for an exact quote, give me an hour or two...)

I think this is less a statement of hard, logistical fact and more a reminded to players and GMs that, if you drop a tank in system A you obviously do NOT have the tank in System B.

This is especially true of independent merchants and adventurers. A military force or an especially well developed trade company with set lines and a fleet of ships will have a greater footprint in any system they regularly use. So while Ship A, jumping from System A may not have Drop Tank A when they arrive in System B, anyone in System A may still be able to pick up, refill and reuse Drop Tank A (especially given the redonkulous prices I seem to recall for them... we are essentially talking about a big empty shell here...)

Obviously answers about how Jump actually 'goes down' would answer a few other questions, like using 'ship to ship fueling', with tankers and hoses replacing drop tanks and so forth.

A consideration too is that there are other militaries in Traveller than the Imperium, and it would only take a few embarrassing defeats in local battles to 'lesser' forces using innovative tactics to create a sea change, as it fairly traditional in military innovation. It doesn't matter than your ancestors going back to the beginning of time have used the rock as the weapon of choice, if your men are dying RIGHT NOW to the sharp rock you can damn well bet that they will start using sharp rocks regardless of tradition.

Conventional Wisdom had it that the aeroplane was useless in warfare as anything other than a scout (and I bet THAT was a hard sell too...) unlike some bastard started dropping bombs over the side with one.

 

[PFVA63]

Hi

I think I'm beginning to come around to the point that some others have already made in this thread, that, if we assume that there will be enough time for the empty tanks to get clear of any gravitational boundary so that they can be re-usable, then I'm not sure why you couldn't instead have your ship hooked to tanker instead.

It would seem that a tanker, with its own maneuever engines would have an even better chance of getting beyond any gravitational boundary in the time between its transferring the last of the needed fuel and the initiation of jump by the recieveing ship, than unpowered drop tanks would and there would be no need for a second ship to come along and collect the tanks, refurbish them (if needed), and then refill and transport them.

Regards

PF