A couple of questions regarding Grav Decks.

[R.Tempest]

 1: How does the station keeping drive on a Jumpship affect the Grav Deck. In the artwork the deck is oriented at a right angle to the direction of thrust. I realize thrust here is very low but would it be felt on the Grav deck. Clearly the Grav decks on Warships are there for use when the ship is not using the Interplanetary drive. I may have asked this on the old board.
2: On a small Grav deck, or any ship mounted one I suppose, would there be enough of a difference in generated G-force between a persons feet and their head to cause dizziness or nausea or pooling of blood in the feet.

[Weirdo]

1: If a unit is intended to use the grav deck and station-keeping drive at the same time(such as a JumpShip or station), then the deck's walking surface can always be built at a slight angle, calculated so that the offset force from the angled rotation is cancelled out by the force from the station-keeping drive.

Given how little thrust a station-keeping drive puts out(in Battletech terms), the angle needed is probably extremely slight.

2: It can, which is why smaller decks rarely rotate fast enough to produce a full 1G. I believe this is addressed in StratOps somewhere. Long story short, you get enough Gs that regular exercise will keep you healthy, or at least, healthy enough to do your job until you can have some R&R on a planet or a larger grav deck.

[Frabby]

The design concept has been called "carousel mounting" on this forum. Basically, the "floor" of the grav deck isn't installed at a fixed angle, it can tilt to accomodate a perpendicular thrust vector from the station keeping drive.

Also, I doubt that BT grav decks look like in the 2001 - A Space Odyssey movie on the inside. I'd rather expect them to be a number of separate cabins, used primarily for sleeping/downtime.

[Weirdo]

Downtime, yes, but probably not sleep. From what I understand, if you're only going to spend part of your day under gravity, to maintain health you need to spend that time working your bones and muscles. You'll want stuff where people are active, such as gyms, maybe a jogging track on larger decks, lounges, bars, stuff like that. Actual unconsciousness time does nothing for you in this regard, so you might as well do that in zero G. I suspect only the largest stations actually put people's quarters on the grav deck.

[Daryk]

Depending how "tall" the ring is, the sleeping quarters could be in the lightest gravity section simply for comfort, with the gyms and such in the "lowest" part.

[Weirdo]

If you've got multiple floors on your grav deck, I'm fairly certain you're already in the realm of largest stations. Remember, most grav decks aren't bicycle wheel structures like we often visualize, more like subway cars on a loop-shaped track. After all, the middle area has to be kept available for structural members and various systems to pass through.

[Daryk]

If it's an Argo style deck, it could have more than one level even though the square footage meter-age is relatively modest.

[Weirdo]

As in the ship from HBS Battletech? I could see that, yeah. There are probably very good reasons why 99% of all space units in Battletech use wholly internal grav decks, though.

[Daryk]

Totally with you on that... moving parts where they can be shot tend not to stay moving for long...

[cray]

Totally with you on that... moving parts where they can be shot tend not to stay moving for long...

The Argo gets away with it because it was specified as an utterly civilian vessel built at the peak of the Star League.

[Kovax]

If you've got multiple floors on your grav deck, I'm fairly certain you're already in the realm of largest stations. Remember, most grav decks aren't bicycle wheel structures like we often visualize, more like subway cars on a loop-shaped track. After all, the middle area has to be kept available for structural members and various systems to pass through.

More likely, PAIRS of subway cars, spaced 180 degrees apart to preserve balance, and probably with some sort of fluid pumping system to equalize their masses as people/objects enter and leave the cars.  Spinning a single heavy object around the central axis would tend to introduce a lot of wobble.

[Weirdo]

I was thinking of a single continuous circle of cars honestly. That way you can still have a 2001-style jogging track, but safety doors can close when needed to preserve pressure.

[cray]

More likely, PAIRS of subway cars, spaced 180 degrees apart to preserve balance, and probably with some sort of fluid pumping system to equalize their masses as people/objects enter and leave the cars.  Spinning a single heavy object around the central axis would tend to introduce a lot of wobble.

I wouldn't worry about the transfer cars' mass versus the tonnage of a grav deck, which includes the gravdeck mechanism and any quarters, SI tonnage, and other facilities included in it. The balancing system would be able to handle much more than the cars.

[Kovax]

Most importantly, if you start work on a gravitational deck in your campaign, finish the job.  You don't want people to accuse you of not playing with a full deck.

[marcussmythe]

Silly question:

How does one enter and exit the grav deck?  Do you stop it?  Are there long doors on the deck and the adjoining, non-rotating parts of the ship that open when they match up (dont get caught by the rotation!), holes in the grav deck ‘ceiling’?  Something else?

My best mental picture had the grav deck laid out below (+’s are ship ‘normal hull’, —————— represents the transfer car track, >>>>>>>> is the transfer car,  and ===== as the grav deck)

++++++++++++++++++++++++++
——->>>>——->>>>>>———>>>>>
==========================


The transfer cars would be at rest relative to the hull, doors open to the hull.  Doors close, transfer cars all accelerate to the speed of the grav deck, and match up with doors on the other side while people come up to 1G.  Doors open, and people in car climb down ladders/stairs onto grav deck.  Doors close, transfer car slows to match hull.  Repeat.

[Alsadius]

I sort of imagine it like The Martian - there's a ring with spokes leading to the centreline of the ship, and at the axis of the ship there's a doorway where you can go from the spinny bit to the non-spinny bit. You're not spinning all that fast in RPM terms (a 100m grav deck producing 1g spins at 3 RPM, and they tend to produce much less than 1g in practice, so you're probably dealing with ~1 RPM), so you can easily just move in and out.

[Weirdo]

Per StratOps page 139, transfer cars is exactly right, though I don't think ladders would be necessary. Easier to just put the transfer car track alongside the grav deck track at the same radius. A full description of what you can put on grav decks and other tidbits is on page 140.

Long story short: The classic grav deck from 2001? That wouldn't provide jack squat in the way of useful gravity. For a deck that small to be useful, it'd have to spin so fast that you'd be horking every time you moved your head because of coriolis effects, not to mention the weird wind effects you'd get between the stationary air in the middle and the air moving many tens of kph at the rim. On top of that, Discovery must have been very weak structurally, since a grav deck that goes all the way to the middle like that leaves no room for a keel or spine.

[idea weenie]

Per StratOps page 139, transfer cars is exactly right, though I don't think ladders would be necessary. Easier to just put the transfer car track alongside the grav deck track at the same radius. A full description of what you can put on grav decks and other tidbits is on page 140.

Long story short: The classic grav deck from 2001? That wouldn't provide jack squat in the way of useful gravity. For a deck that small to be useful, it'd have to spin so fast that you'd be horking every time you moved your head because of coriolis effects, not to mention the weird wind effects you'd get between the stationary air in the middle and the air moving many tens of kph at the rim. On top of that, Discovery must have been very weak structurally, since a grav deck that goes all the way to the middle like that leaves no room for a keel or spine.

I thought the grav deck like that was contained in the 'ball' at the front of Discovery?

Most importantly, if you start work on a gravitational deck in your campaign, finish the job.  You don't want people to accuse you of not playing with a full deck.

That was horrible.  Wish I had thought of it

[Weirdo]

I thought the grav deck like that was contained in the 'ball' at the front of Discovery?

It was, but given that the ball also contains most/all the 'people live here' bits, it's preferable for that area to survive some damage.

[Arkansas Warrior]

IIRC, some of Kevin Killainy’s Chaos Irregulars stories include sections taking place on a grav deck.  The Engadine two-parter, I think.  It’s been a while though, I’d have to read it again to remember much detail.

[marcussmythe]

Per StratOps page 139, transfer cars is exactly right, though I don't think ladders would be necessary. Easier to just put the transfer car track alongside the grav deck track at the same radius. A full description of what you can put on grav decks and other tidbits is on page 140.

Long story short: The classic grav deck from 2001? That wouldn't provide jack squat in the way of useful gravity. For a deck that small to be useful, it'd have to spin so fast that you'd be horking every time you moved your head because of coriolis effects, not to mention the weird wind effects you'd get between the stationary air in the middle and the air moving many tens of kph at the rim. On top of that, Discovery must have been very weak structurally, since a grav deck that goes all the way to the middle like that leaves no room for a keel or spine.

Teach me to RTM first...  thank you, sir.

[Warship]

I seem to remember in one of the earlier novels where Phelan was climbing down onto a grav deck in a Clan ship and not into cars on a track.  Not owning StratOps, have things been retconned?  Is there any new data on the width and height of a deck based on the tonnage?  If not, I would redesign just about every Jumpship with additional decks used as crew quarters.  Although I agree exercising under gravity helps your skeletal and muscular systems, sleeping under gravity must provide a bonus of some sort.  With their relatively low cost in tons and C-Bills, I would redesign every Jumpship to have several.

[Weirdo]

More like people have put more thought into stuff since older things were written. What was written in the past can't be unwritten(and I'm pretty sure they're never going to issue errata), but that doesn't mean the newer stuff can't be more accurate.

My advice? When reading the older stuff, just fix it in your brain, or gloss over it.

[Daryk]

I'd take it as there simply being more than one way to skin this particular cat...

[Warship]

More like people have put more thought into stuff since older things were written. What was written in the past can't be unwritten(and I'm pretty sure they're never going to issue errata), but that doesn't mean the newer stuff can't be more accurate.

My advice? When reading the older stuff, just fix it in your brain, or gloss over it.

I just edited, but it has been about twenty years since I read the novel in question.

[Weirdo]

As I understand, sleeping in gravity does nothing at all for bone/muscle loss. It's activity or nothing.

[Warship]

I am thinking mental health-wise.

[Weirdo]

No idea if sleeping in gravity feels better than sleeping in zero-g, so I don't know if we can assume there's any mental health benefit.

[Warship]

Gameplay-wise, it probably does not matter.  I just keep thinking of a family-owned jumpship traveling around the Inner Sphere just making their way, Firefly-ish.  Maybe they have a couple of Small Craft for the occasional planetary landfall.  But, for the most part, they live aboard ship.  As such, I am thinking they need a more constant exposure to gravity.

[Weirdo]

Children, yes. I think there was a bit in one of the Camacho's Caballeros novels that said when in space, children of the unit spent most of their time on the JumpShip's grav deck.

I imagine that spacer families avail themselves of station grav decks whenever they're available.