Power failure in space

[Grav_Moped]

(Per CT High Guard, the jump requires energy equal to two turns of a power plant of the same rating as the jump, as well as a functioning jump drive and jump fuel of course. Once the jump is initiated, is the power plant throttled back to PP-1 to conserve fuel, or must it maintain output equal to the jump rating - and why if the jump drive is powering the jump field? So many questions.)

My take on CT (except for '77) is that you need Pn=Jn to keep the jump field stable, based on fuel consumption rates. Mind you, based on those rates it's got to be Pn=nameplate Pn regardless of Jn through the duration of jump but that's silly. Mongoose does not need power to the jump drive after jump initiation.

I'm guessing that for multi-week misjumps, the jump field just stays intact of its own accord despite having the power cut. (It shouldn't, but it does. Game mechanics substitute for sensible fictional physics here....) The thing is, the CT misjump rules carried forward from LBB2'77, which only cared about power plant fuel to feed the maneuver drive and nothing else. Long-duration misjumps weren't intended to be total party kills -- that's the purpose of the "ship destroyed" result on the misjump table. They may not have noticed -- or cared -- that the revisions in '81 turned those long misjumps into TPKs.

 

[Grav_Moped]

The "hard fact" about Traveller is that it must be accounted for in the construction.
And we've all looked at the various ship construction rules.....and NONE of them specify backup systems.

Depends on the rules version. Any of the CT versions could have it included, but below the resolution of the build system. It could be part of the bridge tonnage, or part of the 4Td per stateroom, or included in the power plant (backup batteries, but not an actual backup plant -- that'd be a separate line item). Lots of stuff was implied to be there that wasn't specified in the component descriptions -- the "ship's locker" is the best-known example, but landing gear fits the category too.

The other thing to keep in mind is that a realistic minimal "keep the lights and HVAC on" power requirement is a rounding error in Mongoose, and statistical noise in Classic.

From an earlier post of mine:
"We have a real-world example: the International Space Station. Based on pressurized volume (excluding the solar panels and whatnot) it's about 68Td, and averages 102 kilowatts power use. That's the average solar panel output over time; it has batteries to carry it over during the 1/3 of its orbit that it's in the Earth's shadow. 102KW is about 0.00041 EP or 0.012 PP. (Not a typo!)"

Classic (LBB5'80) will not allow you to build a power plant that produces less than 62.5kW (the 1Td powerplant at Pn-1 in a 25Td, TL 7-8 small craft). It also does not track power usage below 125MW (the 1Td manuver drive in a 50Td, 1g small craft).

 

[warwizard]

Just for fun in T4 I once designed a ship where each system had it's own dedicated power built into it's space. The laser turret has a power plant inside to power the laser and ditto with every ship's system. As it was a warship it had extra redundancy, there was no "Main" power plant to take the hits, so I used the procedures outlined in brilliant lances to get a hit table for every 5% of the ship. It still lost ability to jump and lost some computer levels, but it was still firing long after more unitary ships were unable to shoot.

 

[Rupert]

There's this issue where the Navy insists on twin engined fighters.

Someone pointed out, that statistically, if one engine fails, so does the other.

Except when they don't (okay, it was an attack aircraft, but I think it still counts) - the A-4 Skyhawk was single engined.

 

[Rupert]

How do I know owners will work that way? I recently found a man who was paying $150 a month for a "Sump Pump Endorsement" in the insurance for his third-Floor Condominium.

I'll let that sink in rather than explain it.

Ouch.

The "hard fact" about Traveller is that it must be accounted for in the construction.
And we've all looked at the various ship construction rules.....and NONE of them specify backup systems.

There are rules for putting them in if you want them in some. Fire, Fusion, & Steel does specify backup computers as being required, but that's the only back-up or redundancy I can think of that's required by a design system.

It's like escape pods - there are rules for them, but they aren't installed in standard designs, and were never considered common enough to be in the core ship construction rules. Contrast with the Space Opera rpg, where they were 'free' with each starship hull, so all ships had them.

 

[Rupert]

Just for fun in T4 I once designed a ship where each system had it's own dedicated power built into it's space. The laser turret has a power plant inside to power the laser and ditto with every ship's system. As it was a warship it had extra redundancy, there was no "Main" power plant to take the hits, so I used the procedures outlined in brilliant lances to get a hit table for every 5% of the ship. It still lost ability to jump and lost some computer levels, but it was still firing long after more unitary ships were unable to shoot.

The rules don't cover it, but that'd be a maintenance hog, and would carry a mass penalty in extra pipework and power conduits. If you did that in GURPS Traveller it'd be hugely inefficient because most power plants (including fusion reactors) have a base weight just to have a plant, so lots of small plants is quite inefficient.

 

[warwizard]

The rules don't cover it, but that'd be a maintenance hog, and would carry a mass penalty in extra pipework and power conduits. If you did that in GURPS Traveller it'd be hugely inefficient because most power plants (including fusion reactors) have a base weight just to have a plant, so lots of small plants is quite inefficient.

I'm of the opinion that the T4 FF&S rules DO cover it. It says "select power plants from the "power systems" section of this book (page 81)" Engineers: Computer mod (CM) times power output in MW/30 and maintence crew is CM* mass of power plants (Plus a list of other things), all divided by 500. So TL 15 min CM is .2, so one engineer for every 150MW of installed power, and one maintenance tech for every 2500mt of power plants. This tells me all power plants wherever located in the ship are lumped together, and what type they are does not matter, just the power. and fuel usage for the fusion plants is per year, no pipes needed just a tech or engineer with a dewar flask to drop by during annual maint and top them off. (for the .6MW*.1kl/year. so 60l of liquid hydrogen for the smallest plants).

 

[Rupert]

That what I mean by 'don't cover it'. Unless those plants are all utterly stand-alone (which means if one fails all systems it powers go down, no way to draw power from elsewhere) they need to be on a grid, and that grid is more complex because of the multiple power sources. They each need to be mounted, and need their own compartments, etc., that that's the sort of thing that tends to scale more slowly than mass (so many small plants need more volume and mass of mounting, storage, etc.). Maintenance takes longer, if only because the techs lose time moving from one plant to the next.

FF&S2 does cover some of that with the scaling efficiency by size, but I'm not sure it covers all of it.

 

[Carlobrand]

...

The "hard fact" about Traveller is that it must be accounted for in the construction.
And we've all looked at the various ship construction rules.....and NONE of them specify backup systems. ...

I believe CT book 5, or maybe it was Trillion Credit Squadron, discussed having back up systems. And the actual hard fact about Traveller is that quite a lot is not accounted for in the construction. You only need to compare CT Book 5 to MT Referee Manual to realize how much is not accounted for in CT. Even MT takes a few liberties: there are battery design rules, but there's no mention of batteries being needed for fusion plants; one is left to conclude the power plant contains integral batteries to start up the reaction. There's also no specific rules for freshers or kitchens or food storage; they're assumed to be unstated parts of the living space allotments.

 

[warwizard]

I tend to custom design my turret weapons to have the 1 DT cover the entire power needed by the turret and it's weapon/s including overpowering for higher ROF for point defense usage. Point defense does not usually need to do more than surface hits to make the missiles a mission kill. (on board sensors and coms take up a lot of the missile m2, so 2 or 3 surface hits = mission kill) so 1 or 2 damage points for 3 hex range is a fairly small package and power required.

 

[Grav_Moped]

How do I know owners will work that way? I recently found a man who was paying $150 a month for a "Sump Pump Endorsement" in the insurance for his third-Floor Condominium.

I'll let that sink in rather than explain it.

Depends on the building. Flooding the basement might take out the building's electricity. Maybe a centralized HVAC system is vulnerable. Elevators, perhaps -- especially if they're needed for disabled residents' ingress and egress. Sewage outflow might be affected if there's an onsite sewer lift pump. Where's the parking? Is there common (partitioned) storage in the basement? It's not quite as simple as that...

Your point stands as a general case, though.

 

[TamsinP]

One thing that needs to be borne in mind with multiple power plants is that each one will need piping to carry fuel from the fuel tanks. That's a lot of liquid hydrogen being shunted throughout the ship, with lots of opportunities for massive problems if a pipe gets damaged.

 

[warwizard]

I stated above that the T4 FF&S fusion power plants are fueled for a year and the rate is 100 liters per year per megawatt the smallest power plant is .6 MW which needs all of 60 l per year which is co-located with the power plant and a tech can refill it with a dewar flask during annual maintence. No piping needed, and the heat sink... is .0006m2 that is 6 square centimeters. Think of this as a lot of very very small power plants in locations like turrets, low berth bays and life support, and they provide local devices with power, off grid so to speak. They are completly self contained, and get refuelled once a year. The ones covering the life support might be 2X the size, and the hear sink? Well that is two wires through the bulkhead to a thermocouple the size of a deck of cards.

 

[Condottiere]

That's why you have naval architects.

 

[Rupert]

I stated above that the T4 FF&S fusion power plants are fueled for a year and the rate is 100 liters per year per megawatt the smallest power plant is .6 MW which needs all of 60 l per year which is co-located with the power plant and a tech can refill it with a dewar flask during annual maintence. No piping needed, and the heat sink... is .0006m2 that is 6 square centimeters. Think of this as a lot of very very small power plants in locations like turrets, low berth bays and life support, and they provide local devices with power, off grid so to speak. They are completly self contained, and get refuelled once a year. The ones covering the life support might be 2X the size, and the hear sink? Well that is two wires through the bulkhead to a thermocouple the size of a deck of cards.

You won't be carrying around liquid hydrogen in dewar flasks and filling them like it's gasoline. While I'm sure the storage technology will be very mature, it's still a very cold, very 'slippery' substance that will require careful handling. At best we're talking someone going through the whole ship with a fuelling hose. Better hope they don't miss one.

As for the heat sinks - the total area is the same either way, but with many small plants each one requires heat piping to the outside, and thus a hole in the hull.

If they are completely self-contained, with no interconnections, if the power to something vital is lost, you can't supply it from elsewhere until you physically rig lines. If you do have interconnections, they need to be managed and that means current controls and switching, and software and personnel to manage that. Again, doable, but an overhead.

I'm sure it's workable, but there'll be overheads. At the very least, if you use FF&S2 as you mention, you lose the scale efficiencies (and I still hold that you'll need more maintenance on many small reactors than on one or a few large ones).

 

[Commander Truestar]

There are rules for putting them in if you want them in some.

Exactly...
"Put them in if you want them"

That does not mean "assume they are there because it would make sense."

It would have made sense to have lifeboats for everyone on the Titanic.
But it took "actual laws" to force ship builders to have those life boats because Titanic wasn't the only one.....just the most famous

And, BTW, the second most famous was the White Star Lines "SS Atlantic" (you would have thought they'd have learned)
The SS Atlantic was part of the White Star Line and one of the most modern steamships afloat.
Running short of coal, Captain Williams diverted to Halifax to refuel. At 3:15 A.M. on the 1st of April, 1873, while the captain slept, the Atlantic smashed at full speed into the rocky shores and was wrecked, killing ~550 people

So, I don't count on logic
I count on people who want profits and will use that tonnage to make money instead of save lives

The examples march through history and show us no one builds for safety unless the laws make them

 

[Condottiere]

In Alien, it was cheaper to put the crew on ice.

 

[aramis]

In Alien, it was cheaper to put the crew on ice.

In Alien, hyperspace drives conscious folk mad. As in psychotic breaks. Also, they're not cryo... they appear to be chemical hybernation. Excepting the escape pod; it appears to have been cryo.

Since having the whole crew go barmy isn't conducive to maintenance nor commerce... it becomes a needed expense.
Also, barring external interference, Alien's berths seem more reliable than CT's or MT's.

Exactly...
"Put them in if you want them"

That does not mean "assume they are there because it would make sense."

It would have made sense to have lifeboats for everyone on the Titanic.
But it took "actual laws" to force ship builders to have those life boats because Titanic wasn't the only one.....just the most famous

Titanic had boats aplenty... but it couldn't get them all launched. The rated capacity was not sufficient to include 3rd class. 1178 seats, for 1448 1st and 2nd class passengers. (most of the lifeboats were rated by seating; you could overload them once in water.)
The 874 crew, save perhaps the senior officers, were expected to hit the water in life jackets. The Third Class were generally considered more as livestock than passengers, weren't even supposed to go to the lifeboats, and didn't have enough life jackets, either.
Where the big hurt was for the lifeboats, most launched just over half full, and not all hit the water....
In theory, only the third class passengers and the black gang should have died...

Yeah, that's some pretty callous calculus. Titanic was in an era where Class Consciousness mattered, social standing was important, and money could make up for "bad breeding," at least for white folk. (The nouveau riche may not have actually been that popular overseas, but their money sure was.)

But there are more things that went wrong. While we start with insufficient lifeboat drills, add insufficient life jackets, crew unfamiliar with the davits, davits which wouldn't work on either side while the ship was listing (let alone pitching), evacuation plans based upon single failure point need (instead of the 3+ compartments flooded), difficulty in heading to your lifeboat station in a listing and pitching hull, and of course, the callousness of many of the class conscious 1st class and 2nd class passengers. Plus, night-time resulting in many who could have been saved by the boats being unseen by those in them.

Note that while there is a requirement for 100% now, not all of that is boats. A chunk is allowed to be rafts, usually of the inflatable variety.

 

[aramis]

One other thought Book 2 drives already include redundancy of smaller units If they didn't, the first telling hit would take out the whole drive.

 

[TamsinP]

I seem to recall there was a further problem on Titanic because the forward half of the promenade deck (from which passengers were meant to access the lifeboats) was enclosed, which made it more difficult to get into those lifeboats than the ones further aft.