What is contained in a Bridge?

[vegas]

Mike's comments inspired me to think harder about the difference between a small craft and a ship as a clue to what is included in the bridge volume and how much room it takes. Here are some new ideas:

As Mike reminds us, small craft don't have to have a bridge - a couch and a computer will do, but then your 1 dt comp-1 becomes a comp-0. Ergo, minimal controls are a 0.5 dt pilot seat and 1 dt of avionics.

A small craft bridge is 4 dt minimum and has two seats plus life support. Ergo, 1 dt for seats, 1 dt for avionics, and 2 dt for life support.

Here I think a house rule is needed, as a bridge should give a small craft longer endurance since you are adding that life support. I'd rule for a small craft to have longer than 24 hours operations you need BOTH a stateroom (which is RAW) AND a bridge. YMMV.

That is what we can discern just looking closely at the small craft rules. Then we can think about the differences between ships and small craft to get from 4 to 20 dts.

First is the airlock which I judge as 1 dt itself. (I see the wiki says its 0.5 dt, but that is awful small and I can't find a source for that.)

Then there is fact that ships move a lot more air than small craft. Not only must the airlock be evacuated/pressurized, but in 20 (HG) or 30 (B2) minutes, each of the bridge proper, all the staterooms, the hold and engineering, and (not mentioned in RAW but must be true) the flight deck can be as well. I'd think each of these sections would have its own dedicated air pumps and pressure control stations too. At 0.5 dt each that is 2.5 or 3 dt on vacuum control.

Next I'd add at least 2 damage control stations (fore and aft) at 0.5-1 dt each for fire suppression, CBR hazards, hull integrity monitoring and battle damage repair coordination, supplies and equipment.

Finally, starships in particular need to pump a lot of fuel (10 to 60% of volume) very quickly. Similarly, there is a much bigger need for water and sewage pumps on ships than small craft. I'd allocate at lease 1 dt to each of those systems in a pumping room.

Summary minimum volumes:
2 dt bridge proper, 4 seats
1 dt avionics
2 dt life support
1 dt airlock
0.5 dt airlock pump & control station
2 dt auxiliary vacuum pump control stations (4x 0.5 dt for bridge, staterooms, hold, eng)
1 dt damage control stations (2x 0.5 dt each)
2 dt fuel, clean water, & sewage pump rooms

That is 11.5 dt minimum right there.

Personally, I'd add 1 dt to the bridge just for more access/mobility for 4 people. I wouldn't have a problem bumping up ship life support another 2 dt either given all of the components. DC could easily be another dt or more. Those 3 changes add 4 dt for 15.5 dt. If you are willing to add the ships' locker (and I am coming around to the idea) I'd also say there should be an EVA ready/store room adjacent the airlock as well as a weapons locker. If those are 1 dt, 1dt, and 0.5 dt respectively, now we are at 18 dt. The last 2 dt could be distributed through the ship (lights, comms, power, plumbing, vents, gravity, etc.)

That would get us comfortably to 20 dt. Apparently there is a lot of overhead in those volumes because a 100 dt and 1000 dt ship can make do with the same 20 dt, but I'm OK with that. A lot of the space IS access to my mind.

EDIT

on still further reflection, 2 dt for life support is for a 20 dt small craft. a 99 dt small craft has a ~20 dt bridge and still only 2 dt are couches/avionics. Is our "bridge" actually 18 dt of life support? That doesn't seem right either, but it does encourage me to raise the life support dt on a ship up from 2.

 

[Straybow]

I would note that in the old days a cockpit for a crew of 4 (pilot, copilot, navigator, engineer) would fully fit within 1 dT (14 cumets, approximately 8' cube in freedom units). It would be barely tall enough for an average man to stand. The cockpit wasn't the full width of the aircraft body, as the fuselage would be narrowing to a cone-like nose, and the cockpit was usually perched at the top, not the whole height of the fuselage.


People keep forgetting that 1 dT is a stupidly large volume to use as a basis of measurement. 4 workstations in 14 cumets comes to 3.5 cumets each. Workstations don't need full 3.5m height typical of floorplans. They can use areas where the hull is sloping.


All those other things people describe aren't "bridge." They're needed, and they can and should be invoked to explain some of the overly large requirement holding over from the original game. But they aren't "bridge."

 

[Grav_Moped]

A small craft can get by with 1.5Td "bridge" (Mod/1 and 1 seat) up to 99Td. Granted, this substitution costs MCr1.525-MCr1.925 more than the default option (lowest difference at 99Td, highest at 20Td or less), but oddly, it doesn't seem to have any in-game effects on performance or combat capability aside from the initial computer down-rate.

It does make computer upgrades far more expensive though.

Wait. Can a small craft have two computers? Use 1 Mod/1 for the flight controls, and a second Mod/1 for the weapons systems. This gets you Mod/1 capability for the same tonnage as a Mod/2 down-rated to Mod/1, but for MCr7 less!

Conceptually, these are:
Computer and a seat or two as bridge: fighter cockpit, minimal radome (think F-16, not F-15)
Small craft bridge: Airliner flight deck including forward radome (this is F-15 and early commercial aircraft radar sized)
Starship bridge: Oceangoing ship bridge

 

[AnotherDilbert]

Wait. Can a small craft have two computers?

Yes, of course.

Use 1 Mod/1 for the flight controls, and a second Mod/1 for the weapons systems.

No, only one can be operational at any given time. The other(s) are reserves in case of damage.

 

[AnotherDilbert]

The bridge is well defined since time immemorial:

The Bridge: All starships must allocate 20 tons displacement for basic controls, which include guidance radars, drive and power plant controls, communications equipment, and other devices required for proper control of the ship. Basic controls cost CR 500,000 per 100 tons of hull mass displacement.
The basic controls do not include the ship's computer, which is installed adjacent to the bridge and is available in a variety of configurations, ...

The "bridge" isn't a room, it's all the equipment you need for C³I including sensors, communications (internal and external), avionics, and crew workstations.
The control workstation in Engineering: "Bridge".
The intercom system: "Bridge".
The command systems that allows control of the drives from the control room: "Bridge".
The local "wifi" network: "Bridge".
Radar antennæ: "Bridge".
Radio communication system that can reach lightseconds: "Bridge".
And, of course, the central control room: "Bridge".



Life support, galleys, or air locks are not part of the bridge, but "stateroom" tonnage.

 

[vegas]

I would note that in the old days a cockpit...

Analogizing to a cockpit isn't great. The human endurance required is longer - 24 continuous hours - and so is the machine endurance. There is no ground crew for maintenance for weeks at a time so reliability needs are higher and maintenance must be performed underway. That means more redundancy, more access space for repairs and maintenance, and more ergonomic constraints than a terrestrial cockpit.

All those other things people describe aren't "bridge." They're needed, and they can and should be invoked to explain some of the overly large requirement holding over from the original game. But they aren't "bridge."

The RAW are quoted up thread and they are explicit that bridge volume refers to much more than the bridge proper.

 

[vegas]

Life support, galleys, or air locks are not part of the bridge, but "stateroom" tonnage.

I agree it would make more sense for life support to come out of stateroom tonnage (size scales with number of bodies) but the CT small craft rules are explicit that bridge includes life support.

I agree galleys probably aren't bridge - they aren't operating equipment - though I wouldn't die on that hill if someone disagreed.

Airlocks on the other hand I'm more inclined to include - they are required for operations along with all the auxiliary vacuum control for other sections. Vacuum control is a core life support function along with other atmospheric controls.

 

[Grav_Moped]

Very small craft wouldn't have airlocks, but instead depressurize the cockpit/bridge.

 

[vegas]

Yes, as per RAW. Hence the air lock is something that is a part of a ships bridge 20 dt but not part of a small craft 4 dt bridge.

 

[Grav_Moped]

Yes, of course.



No, only one can be operational at any given time. The other(s) are reserves in case of damage.

Rules lawyering: Simply by being committed to operating the flight controls and navigation, the first one is reduced to zero factor. The "weapons can still be used" statement means they're being fired without computer assistance.

At that point, the second computer is the backup, placed into operational status.

Yeah, it's a weak argument. But then, the whole computer-as-bridge thing shouldn't be providing sensors equal to what you'd get from a 4Td-minimum bridge anyhow (and under LBB2, military-grade sensors!), but it does.

 

[AnotherDilbert]

I agree it would make more sense for life support to come out of stateroom tonnage (size scales with number of bodies) but the CT small craft rules are explicit that bridge includes life support.

Small craft couches explicitly includes life support. A small craft bridge provides two couches (inc. life support for two).

The bridge doesn't generally include life support.

Staterooms: Quarters for the crew and for high and middle passengers are provided in the form of staterooms, containing sleeping and living facilities. Each stateroom is sufficient for one person, and contains all important life support considerations.

I agree galleys probably aren't bridge - they aren't operating equipment - though I wouldn't die on that hill if someone disagreed.

Airlocks on the other hand I'm more inclined to include - they are required for operations along with all the auxiliary vacuum control for other sections. Vacuum control is a core life support function along with other atmospheric controls.

I can't provide a specific quote for air locks, but galleys are explicitly included in "stateroom" tonnage.

Staterooms require four tons at a cost of Cr500,000 per stateroom. Staterooms actually average about two tons, but the additional tonnage is used to provide corridors and access ways, as well as galley and recreation areas.

I would include air locks in the "corridors and access ways" category, hence in the stateroom tonnage.

 

[BRover]

I agree it would make more sense for life support to come out of stateroom tonnage (size scales with number of bodies) but the CT small craft rules are explicit that bridge includes life support.

I agree galleys probably aren't bridge - they aren't operating equipment - though I wouldn't die on that hill if someone disagreed.

Airlocks on the other hand I'm more inclined to include - they are required for operations along with all the auxiliary vacuum control for other sections. Vacuum control is a core life support function along with other atmospheric controls.

This is my thought. Galleys and Med bay and even maybe an office or so (to store ships papers and archives and even a few hardcopy manuals for emergency?) are part of commons and life support = stateroom cubic. (ETA: Airlocks beyond the first would be part of access ways, as per AnotherDilbert.)

First airlock and controls and avionics/sensors/commo equipment are bridge, as well as the ship locker. (Small craft have basic life support, as part of the couches. Likely big bridges would too, as emergency equipment, duration less than the stateroom's month.)

Errant thought: how might higher/lower tech affect life support duration? I'm thinking TL 6-7 (1960's-80s) is pretty limited, with air tanks and scrubbers but not so much recycling of O2 etc. By TL 10+, surely recycling is likely, offering progressively better duration, as losses per cycle are limited?

 

[Condottiere]

Operating only by computer would depend on how much automation is involved.

The passenger doesn't have a dedicated workstation, and if he exerts physical control, might only be able to do so through a touch screen.

 

[AnotherDilbert]

Rules lawyering: Simply by being committed to operating the flight controls and navigation, the first one is reduced to zero factor. The "weapons can still be used" statement means they're being fired without computer assistance.

No, only one at a time:

SPARE SYSTEMS
Spare jump drives, maneuver drives, power plants, computers, and screens may be installed in a ship to take over in the event that the main unit is disabled.
These are backup devices only and may not be in operation at the same time as the main device.

Yeah, it's a weak argument. But then, the whole computer-as-bridge thing shouldn't be providing sensors equal to what you'd get from a 4Td-minimum bridge anyhow (and under LBB2, military-grade sensors!), but it does.

Agreed, it's a clunky system, but it works all right under LBB5:
Civilian or budget small craft lacks bridges, and are not very combat effective.
Heavy fighters have large computers and bridges and are at least marginally effective.

Note that only starships have defined sensor performance in LBB2:

Ordinary or commercial starships can detect other ships out to a range of about one-half light-second; about 1,500 millimeters. Military and scout starships have detection ranges out to two light-seconds; 6,000 mm or 6 meters.

 

[vegas]

@AD,

I love me a rules a nerd, and you are a great one. However, appealing to B2-'77 definition of a stateroom isn't applicable (unless that is your only version) because by B2-'81 it was revised and the reference to life support was materially changed:

Staterooms: Quarters for the crew and passengers....No stateroom can contain more than two persons however, as it would strain the ship's life support equipment.

No longer does a stateroom "contain all important life support considerations", instead now occupancy is limited to not strain "the ship's life support." That revision should not be missed. What's more, B5 makes it explicit what is in a stateroom:

Staterooms actually average about two tons, but the additional tonnage is used to provide corridors and access ways, as well as galley and recreation areas.

Life support is conspicuously absent from that definiton. Life support is most certainly operating equipment. It fits under the bridge definition far better than the stateroom definition by 1981.

As for calling an airlock part of "corridors and access way", while not explicitly wrong is ignoring that airlocks and associate vacuum control are essential ship operating functions for life support and not merely for ordinary passage nor an ordinary portal. I think they fit under the bridge definition far better.

 

[mike wightman]

I agree.

Let's say we build a 199t ship and have one stateroom. Does that mean there is no life support/grav plates/acceleration compensation anywhere else in the ship? No corridors, no crew spaces, no accessways.

It makes a lot more sense for the basic life support etc for a ship to be included in the 'bridge' with the additional load taken by staterooms. The bare minimum for up to 20t is 4t, rising to a bare minimum of 20 tons for up to 1000t of ship, after which 2% becomes the overhead for controls, avionics, comms, sensors, basic hull life support and gravitics, airlocks, accessways, and of course the ship's locker

 

[vegas]

Errant thought: how might higher/lower tech affect life support duration? I'm thinking TL 6-7 (1960's-80s) is pretty limited, with air tanks and scrubbers but not so much recycling of O2 etc. By TL 10+, surely recycling is likely, offering progressively better duration, as losses per cycle are limited?

I agree. At lower tech levels resupply is required because there will be losses. But at what time interval? This would be calculable/SWAGable with enough research, but then would also really require firming up how much volume is dedicated to life support. Probably more trouble than I'm willing to entertain...

 

[AnotherDilbert]

However, appealing to B2-'77 definition of a stateroom isn't applicable (unless that is your only version) because by B2-'81 it was revised and the reference to life support was materially changed:

I see no contradiction, just different levels of incompleteness...

By LBB2'81 a ship can have 1 "stateroom" and have life support for 2 people, or it can have 100 "staterooms" and life support for 200 people; it would seem that life support is proportional to the staterooms, not the bridge.

What's more, B5 makes it explicit what is in a stateroom:
Life support is conspicuously absent from that definiton.

Life support is explicitly included in small craft couches and staterooms.

Life support is not specified at all for ships, so I assume ship life support works like small craft life support, since that is the only discussion of life support in LBB5'80.

Life support is most certainly operating equipment. It fits under the bridge definition far better than the stateroom definition by 1981.

Maybe, but by LBB5'80 the bridge is only for control:

The Bridge: Every ship requires a bridge for control of the drives and electronics and for navigation. ... The bridge contains all necessary equipment for the control of the ship with the exception of the computer.

As far as I can see the LBB2'81 mention of "... and other equipment for proper operation of the ship" means basically the same as the LBB2'77 and LBB5'80 "... equipment for the control of the ship ...", otherwise you could just as well include the power plant into the bridge...

As for calling an airlock part of "corridors and access way", while not explicitly wrong is ignoring that airlocks and associate vacuum control are essential ship operating functions for life support and not merely for ordinary passage nor an ordinary portal. I think they fit under the bridge definition far better.

Agreed, it's a matter of opinion.

I would say it fits much better as a part of "stateroom" tonnage. If we have 100 staterooms we need far more air lock capacity than if we have 1 stateroom.

We can even make fully automated ships with a few robots and brains. That ship would not require any staterooms nor air locks.

Again, needed air lock capacity is proportional to staterooms, not the bridge.

 

[AnotherDilbert]

Let's say we build a 199t ship and have one stateroom. Does that mean there is no life support/grav plates/acceleration compensation anywhere else in the ship? No corridors, no crew spaces, no accessways.

Life support and grav plates are two different cases.

Grav plates (and hence acceleration compensation) is in the decks and proportional to hull size, not the bridge. I assume it's included in hull cost at insignificant tonnage, but that is just my supposition of course.

... the grav plates integral to most ship decks, and which allow high-G maneuvers while interior G-fields remain normal.

No corridors, no crew spaces, no accessways.

That is all "stateroom" tonnage.

 

[kilemall]

So are you saying that a portion of the bridge tonnage is for life support overheads, grav plates, acceleration compensation that sort of thing? Airlocks, docking tubes, landing gear...

I'm saying the starships are more complex beasties running a lot longer then short duration small craft and that the 20t bridge scales to the degree of extra automation the smaller ships need to maintain usable space, plus jump control/navigation, plus better sensors then the small boats.


Max automation comes with the 100-ton scouts, 10x the minimal bridge at 20% volume and that requires just a pilot. Next are the traders at 10% volume and 3 'systems crew', then the fat trader at 5% of ship's volume. It just drops from there to the more normal 2%.


Think more like those are 'ship's robots' subsumed in the bridge tonnage, highly deterministic and 'dumb' then the usual mobile variety but built for maximum redundancy and reliability.


I also have default sensors that are 'just' planetary ranged, but much more capable then the 'Cessna' level of avionics for the small craft.



Big part of why the Type J is so important for prospectors, one man operation scanning and running a ship for weeks out there.


If you like, it would make sense to charge off the airlocks, landing gear, tubes and ship's locker to the bridge space. For gravitic decks and compensation, I would charge that off to the M-drive, and life support to the stateroom tonnage.