"High Guard" and fuel skimming

[E.D.Quibell]

Then, show me the rule for partial power usage, where are the tables or rules? Well?

Page 64 RM _1 Power Supply_: I quote "install as many kiloliters as are necessary to achieve the desired power supply" and the key word is "desired". Each Power Plant unit can be caculated independently as given in the tables on the same page.

Prid pro quo: Show me the rule requireing full power outage of a power plant. Where are the tables or rules? Well?

Best regards,

Ewan

 

[HG_B]

Page 64 RM _1 Power Supply_: I quote "install as many kiloliters as are necessary to achieve the desired power supply" and the key word is "desired". Each Power Plant unit can be caculated independently as given in the tables on the same page.

Prid pro quo: Show me the rule requireing full power outage of a power plant. Where are the tables or rules? Well?

Best regards,

Ewan

Waiting for the rule in the book that shows how to do partial power plant power for different M drive speeds for installed drive...

Well?

 

[E.D.Quibell]

Waiting for the rule in the book that shows how to do partial power plant power for different M drive speeds for installed drive...

Well?

Done that.

Where's yours?

Regards,

Ewan

 

[HG_B]

Done that.

:rofl:

 

[mike wightman]

Ok children - play nice.

To answer HG_B's question - a MTJ article (DGP's canonical MT magazine) adressed the issue of running power plants at various output levels for fuel conservation because people noticed the obvious flaw in the rules that you could run the power plant at a reduced energy output for general use and only use full output for combat.

By the way they allowed it since one of the big problems of MT was the fuel required for power plants (it's why they reduced the jump fuel required per jump)

It may have been in a Challenge article as well - I'll go check.

 

[navanod]

Gentlemen, if I may interject for a moment, CT mentions powering down the fusion plant in JTAS 14, page 25. The text there suggests that it is possible to 'power down' the plant. The relevant bits (emphasis mine)

Ships in non-combat situations can be "powered down" to reduce the fuel consumption of the ship's power plant. The minimum level of power plant is one, which is enough to power the life support systems and maintain maneuver drive-1, jump drive-1, etc. No energy using weapons may be used in powered down condition. Ships which spend an entire 4 week period in powered down state reduce the fuel consumption of the power plant to the powered down level.

If a ship is caught by an enemy in a powered down state, the crew may attempt to bring the power plant up to full blast. One turn is required for each level of power plant to be restored. No energy-using weapons or shields may be operated during this "stoking-up" period, and agility is reduced to one.

That suggests to me that output of the power plant can be varied, you don't have to power it down to just the minimum, and that anything less than full power is insufficient to power energy weapons. The one turn per level to power it back up provides a significant drawback - several turns with no screens, energy weapons, and an agility of 1 makes you a sitting duck long enough to ensure you're a crispy sitting duck.

Granted, it's an optional rule in CT, but does show some precedent in canon (if JTAS articles can be considered canon). Just my two pence.

*Ah, Mike beat me to it.

 

[mbrinkhues]

Actually "Assignment:Vigilant" and IIRC the Challenge Article "Ships of the Black War" also had rules about regular and peak performance. A:V was more detailed showing various tricks in ship design like

+ No life support/gravitics in the fuel tank
+ Booster power plants that only activate if full power is needed
+ And IIRC also variable output PPlants

Traveller ships can have more than one PPlant in Mega without changing the total size of the plant unless you get very small (Size efficiency factor) so every design can be designated "with booster plant" easily.

=============================

SDBs have the common "boat" advantages with more internal space availabel than a ship so they can use a bigger plant to get better agility than "ship". And they can use a hull shape that is optimized for athmosphere duty (Many ships are not).

Bringing the fusion plant online was done quite fast in Traveller, well within a ship combat round so the system will give you surprise

Not sure if there where rules for "scanning against background radiation". If yes the SBD "looking out" would have less problems than the fuelers "looking in"

Quite a few ships do not self-refuel but rather use fuelers. And those are "easy prey" for an SDB. Some ships can "emergency refuel" i.e the AHL but normally should not do that (Arrival Vengeance states that the ship was specially modified and reenforced in the "neck" region before it's last big voyage)

 

[E.D.Quibell]

:rofl:

Try defending your position, as opposed to being annoying.

Ewan

 

[pmbnss]

Fuel Skimming

Something to consider about fuel skimming in combat is the time requirement..

At first blush, Adventure 5 (Trillion Credit Squadron) pegs it at 7 combat turns to fill the tanks (pg. 39), and if you are dependent on fuel transfers, add another 6 turns to the length of the combat. I'm not sure off the top of my head how CT purification works out on the time issue, so I'll ignore it for now.

So at minimum you need to "hold the line" for those seven turns while your reserve refills, plus then refuel the folks who held the line.

The movement rules in Book 2 are also telling. To enter orbit from a Large Gas Giant's 100D limit, your pilot must decelerate the ship from insystem speeds down to an "orbital speed", say 1G, - that is covering 14,000,000 km to the atmosphere. Then it's another 14,000,000 km back to 100D limit to jump away. At 6G acceleration, and assuming no gravity from the Gas Giant, that is another 14 combat turns each way, so at minimum, 35 combat turns. Probably more with cycling ships out of the line, and slower ships. At 3G, you can figure on about 20 turns each way (times calculated using the Book 2 trip time formula, then rounded).

Small Gas Giants are not as dangerous, with only 5,000,000 km to cover from 100D limit to orbit, so 9 and 12 turns, respectively, each way.

If you are assuming a full stop to Jump universe, then the trip time is considerably longer from the 100D limit to orbit (on the order of 28 turns one way at 6G, and 40 turns one-way at 3G).

So, best speed at a Small Gas Giant with a 6G fleet, you are talking probably 32 potential turns of combat (9 from the limit to orbit, 7 for half the fleet to skim atmo, 7 for the other half, and then 9 more to burn to the 100D limit and jump). Assuming no battle damage, of course.

Alternatively, there is nothing saying you cannot handle skimming operations as separate battles, particularly if you don't mind mashing bashing Book 2 into Book 5 a little bit. Range from 100D limit to orbit is 45LS, effecting tracking range for combat is 3 LS, so elements of a fleet that disengage by acceleration could "press forward" to orbit to skim. Meanwhile, the Defender could divide forces into a interception force (the first battle) and hold SDBs in "stealth mode" in the atmo, targetible at only 1/8 LS - well within Book 2, and therefore arguably Book 5 combat range.

So not only does the skimmer need to disengage by acceleration, but also with escorts to hold off the SDBs.

-Peter

 

[aramis]

CT Purification is 8 hours post grab. 24 turns.

 

[Maccat]

adventure ?? Secrets of the ancients had a good bit on a floating city in the depths of a gas giant, took M3 just to hover at depth, had breakdown of temperature, pressure limits. It even has sensor stuff.

There's a disparity in high guard and TCS and the ships book for CT on the time requirements, i consider it ideal to do work ups to process the fuel *fast* to match the TCS turns, haven't gotten around to it yet <s>. Then again there's no real fuel tanker design for fleets that copmes to my mind offhand.

for HG i've always envisiged it's game effect of limiting the agility of ships performing refueling maneuvers, so they are more vulnerable to attack. Azhanti High Lightning used dedicated fuel shuttles, many ships don't have them, and a dedicated maneuver and armored vessel will have advantage over ship needing jump fuel tankage, akin to battleships vs battle riders.

There are threads discussing the feasibility, adviseability etc of even doing GG skims at all. From system design using scouts, a lil military/naval outpost on a GG moon seems much better for refuelling. Always struck me as submarune warfarish, atm limited speed., M required to not sink, etc.

So rulewise ships more vulnerable to crashing, a maneuver drive hit can result in an involuntary (and fatal) deorbit. Maneuver is limited, either to resist the GG grav, atm drag, or both. Also vectors come intoplay for orbit, atm effects. A hull breach could burst through bulkheads under stress from high stresses. Weaponry ranges likely less effective than vacuum, also no PA fire in atm.

Another view is the screening of the planet itself, high guard the ships in orbit to detect approaching vessels, to prevent over the horizon ambush effect

anyhow hope this helps!

 

[samuelvss]

Tend to agree with Maccat and others about the tactical disadvantages to skimming, and the advisability of the navy setting up fueling stations. I haven't worked the math, but I would assume that skimming is not something that a fleet with anything less than considerable superiority could do opposed.

I have assumed, in my limited travels in the CT canon, that various fueling sources wold be used if the tactical situation permittted. One of these would be deep space caches in classified locations. I realize this brings up the whole 100D debate, which I will acknowledge and avoid in this post.

An invading navy, and a navy under other tactical/logistical constraints, will, however, generally have to be prepared to skim. It will presumably do so at the least defended GGs.

We do things that make us vulnerable tactically all the time. We do them for important reasons, and we take what precautions, but do them we must. Logistics are commonly military force's "soft spot."

I would use 0 agility for skimming ships, and agility cap for SDBs of Agility minus Gs of altitude where the SDBs are lurking/engaging from. I would be insterested in anyone's ideas on sensor play for CT in this situation.

 

[RainOfSteel]

Did anyone ever solve the issue of heating from compressing gas during fuel skimming?

I remember discussions on the TML that basically stated that skimming sufficient fuel to fill the tanks would produce enough heat to melt the entire vessel.

 

[aramis]

Two means of skimming:
1- fly-through
2- settle in and compress

Method 2 allows shedding heat, but requires at least 2 g's to work, preferably 3.

 

[RainOfSteel]

2- settle in and compress

I'll take that one.

 

[Andrew Boulton]

I remember discussions on the TML that basically stated that skimming sufficient fuel to fill the tanks would produce enough heat to melt the entire vessel.

So would using the jump drive.

And in TNE, air/raft use HEPlaR...

 

[atpollard]

Did anyone ever solve the issue of heating from compressing gas during fuel skimming?

I remember discussions on the TML that basically stated that skimming sufficient fuel to fill the tanks would produce enough heat to melt the entire vessel.

... just out of curiosity, what is the melting point of partially collapsed matter (superdense, bonded superdense) and would it fail slowly like steel or suddenly like ceramics?

 

[RainOfSteel]

So would using the jump drive.

Oh, I remember, the part about a fusion process never being able to use up so much hydrogen.

Graeme Batho's big "how jump works" article from back in 2001 gave a fascinating idea on what was happening to all that hydrogen, but despite how good a job was done, I never liked that explanation.

 

[RainOfSteel]

... just out of curiosity, what is the melting point of partially collapsed matter (superdense, bonded superdense) and would it fail slowly like steel or suddenly like ceramics?

Personally, I have no idea. If the fuel skimming issue hadn't been pointed out by people with knowledge of physics, I would never have known about it. Presumably, they knew about ship's armor, too.

 

[aramis]

The big problems with the settle and compress:

• anything NOT armored with hydrogen resistant armor (probably via magnetics and electrostatic charging) is going to be pervaded by small amounts of hydrogen and helium after a while.
• Air temps cold enough to make the compression heating welcome
• pressure differentials requiring strong hull shells (10's of ATM)
• airlock seals exposed to mild corrosives.

Given the rules for fuel storage, that first is likely already solved by TL9. The mild corrosives are not usually concentrated enough to do significant damage... but it's a minor increase to maintenance long term, I'd think.