Shipboard Chronometers & Jump Space

[Condottiere]

There are probably three types of time kept:

1. Universal time, to keep the empire coordinated.

2. Planetary time, similar to GMT, to keep planetary activities coordinated.

3. Local time, whether on a particular meridian or on a starship.

 

[simonh]

There are probably three types of time kept:

1. Universal time, to keep the empire coordinated.

2. Planetary time, similar to GMT, to keep planetary activities coordinated.

3. Local time, whether on a particular meridian or on a starship.

Agreed. How planetary time is worked out will vary depending on local history and needs. For example, will the length of a local hour be equivalent to an Imperial hour, or be based on a convenient sub-division of the local day?

Let's say a planet has a rotational period of 31.5 standard hours. What might it's clock look like? That's probably at around the upper edge of a day length that the human body can adapt to.

There are many ways you could do it. Come up with a local hour (and local minutes/seconds) that evenly fit into the rotational period. Stick with standard seconds/minutes/hours and have a fractional short-hour immediately before midnight. In the latter case I suppose you'd have to mostly give up on clock dials.

Simon Hibbs

 

[kilemall]

I have a different view on the importance of time to a starship operator.

I believe it is EVERYTHING, at least in terms of defining a jump, astrogation in general, and defining a detection, position and course.

In terms of a jump, consider that every stellar system is in motion.

Our own solar system is travelling at 828,000 kph. A jump plotted just a year ago would put the ship a LONG way off from the 100D limit because the entire system moved away from that position at considerable speed.

The jump Generate program has to deal with system movement, orbital movement of the body you are trying to get as close to, and if you are using a random time assumption that is not entirely known, enough of a margin at the extremes to not be too close to the planet on emergence (effectively having to allow for a very large safe zone).

You need to know the PRECISE time in order to make use of any mapped hazard database. An asteroid that will cause a collision right this minute is likely not a hazard just 5 minutes ago or 5 minutes later.

Don't tell your navigator you cannot give him/her/unspecified alien gender the time cause it's not important, there will likely be a scene, quite possibly a sulking, and maybe constant ship log entries protesting unsafe conditions which will be used by your insurance company in the suit regarding refusing damage payment for the comet you collided with.

Finally, if you are reporting a detection or even an enemy position, it is vital to have some sort of timestamp or you will lead friendly forces astray.

A pirate location sent to the local SDB patrol that is 20 minutes old and they don't know it means that pirate ship could be going a lot faster when they receive and plot an intercept. The zone of possible pirate movement they are working from will be wrong and they will have greater chances to miss an intercept if they are not in direct detection range.

Similar problems obtain with naval battle contact reports that do not have a proper timestamp.

So IMTU this and the 'ship time does not match external reference time' issue is resolved by proper formatting of location and event logging.

A detection result (ship, navigation hazard, destination, etc.) is formatted with TIME FIRST, so that accurate decisions and logging can occur.

Example of typical report-

Contact 15120-00032, designated Threat 2 on our plot, Time 15120-23:07:00 HACK, contact position MARSREF bearing 270 by 136, 11.2 million kms, contact course SOLARTRUEREF heading 190 by 200, 200,000 meters per second.

Normally one wouldn't want to use shifting references, probably a hurried report to get across relative position quickly in battle.

Note that without an accurate time, even a reference to a well known astrogation feature to report the plot by would be inaccurate, have to know the time to get any relative position right, even if you are using something like Galactic True.

Although any self-respecting TL30 Jump-128,000 capable craft would be using the Big Bang as the reference AND time point, please we aren't LOCAL IGNORANT SAVAGES.

Re: logging different ship time, IMTU since time passes LONGER on the ship then in the 'real world', I have the convention YYYY-MM-DD HH:MM:SS@DD:HH:MM:SS, with the time after the @ being the time that has elapsed on ship.

So 2215-06-21 10:15:23@00:00:00:00 is the time the ship went into jump, 2215-06-21 10:15:23@02:18:09:42 is when the surprise birthday party the steward put on for one the passengers occurred.

 

[simonh]

I have a different view on the importance of time to a starship operator.

I believe it is EVERYTHING, at least in terms of defining a jump, astrogation in general, and defining a detection, position and course.

Absolutely agree, per my first post in the thread.

The base rules seem to assume that planets and systems are not movign significantly relative to each other when it comes to jump navigation, but ships will actualy spend a lot of time matching vectors with their destinations, and jumping to the right place at the right time plays a big part in this.

Simon Hibbs

 

[Enoki]

The US Navy crewman often lives by a 22 hour day when afloat... the 7 watch system, but the crewman's personal day is 6 watches. And if your sleep falls on a dog watch, you get 6 hours instead of 8. (And evntually, it hits both dogs, and then you have 4 hours of sleep... but I've heard from a number of sailors that those days, you take your personal time watch as a nap...)

And the sumariners do 4 long watches (6hr) per day but normally on a 3 watch sleep rotation, resulting in an 18-hour personal day.

the UK's RN also used and sometimes still uses the same watch system.

http://www.navy.mil/navydata/questions/bells.html
http://www.globalsecurity.org/military/library/policy/navy/nrtc/12018_ch3.pdf
https://en.wikipedia.org/wiki/Watch_system

Normally, I wouldn't cite Wikipedia, but the illos are excellent, and it shows a diversity of watchstanding time-systems. I can't find my old Bluejacket's Manual to look at what it says - but I recall it had 3 different watch rotation systems.

I spent 27 years in the US Navy. I know how watches are stood. With the USN they are normally 4 hour watches but a 6 hour can be used instead. Typically you stand 1 watch and have 2 to 4 watches off.
So, you have either 6 watches in a day (4 hour) or 4 watches (6 hour). Normally all watch standers in a particular division of the ship stand the same watch rotation and the norm is to have a minimum of 3 sections of watch standers.
Your off watch time is used to do maintenance, sleep, eat, etc. You might rotate watch stations or you may have the same one all the time.
GQ / Battle stations is a different watch bill. Everybody has an assigned station and if yours is a normally manned post you relieve whoever is on watch when GQ is called and stay on watch until GQ ends.
There are some other oddities in there. Flight deck crews on carriers don't do a watch system. There is one deck crew and they operate from flight quarters to end of flight quarters, often a 16 hour work day.

 

[Patron Zero]

Maybe a short-cut answer to be about establishing a 'Greenwich' meantime would be that an Imperial communications satellite, in orbit around the main-primary world of a sector/sub-sector, would also 'ping' out the established time.

Navigational buoys found near jump-points would also have that capacity for convenience.

 

[Condottiere]

Probably some (or a series of) astronomical phenomenon, with a very precise calculation of the distance from each solar system to it (or them).

 

[BlackBat242]

I spent 27 years in the US Navy. I know how watches are stood. With the USN they are normally 4 hour watches but a 6 hour can be used instead. Typically you stand 1 watch and have 2 to 4 watches off.
So, you have either 6 watches in a day (4 hour) or 4 watches (6 hour). Normally all watch standers in a particular division of the ship stand the same watch rotation and the norm is to have a minimum of 3 sections of watch standers.
Your off watch time is used to do maintenance, sleep, eat, etc. You might rotate watch stations or you may have the same one all the time.
GQ / Battle stations is a different watch bill. Everybody has an assigned station and if yours is a normally manned post you relieve whoever is on watch when GQ is called and stay on watch until GQ ends.
There are some other oddities in there. Flight deck crews on carriers don't do a watch system. There is one deck crew and they operate from flight quarters to end of flight quarters, often a 16 hour work day.

Funny - in my 360 days aboard CV-61 USS Ranger from 11/85-12/87 I never once stood a 4-hour watch - or a 6-hour.

It was 12 consecutive on, 12 consecutive off, 7 days a week. 0700-1900 or 1900-0700.

I was in AIMD, and we had only two shifts. The 4-section watch only activated once we were in port, and then only to determine liberty - actual work schedules remained the same.

And how do you think we ran flight ops around the clock for days at a time? Not on one flight deck crew... we had shifts there as well.

 

[aramis]

Funny - in my 360 days aboard CV-61 USS Ranger from 11/85-12/87 I never once stood a 4-hour watch - or a 6-hour.

It was 12 consecutive on, 12 consecutive off, 7 days a week. 0700-1900 or 1900-0700.

I was in AIMD, and we had only two shifts. The 4-section watch only activated once we were in port, and then only to determine liberty - actual work schedules remained the same.

And how do you think we ran flight ops around the clock for days at a time? Not on one flight deck crew... we had shifts there as well.

A UDT I once knew said 'There be 4 US Navies... Subs, Surface, Carrier, and us." He later clarified "Us" to include both the Seals/UDT's, and the Seabees.

Plus, navy regs allow the captains to use any of several watch patterns.

The 2 every 6 of 7 pattern predates WWI, and was in use up through at least 2010, when a documentary filmed aboard a CV, with 3 different watch schedules in use. I remember watching it on cable... IIRC, it was 2of 6 on 7 (the old RN system) for ship's personnel except officers ( including CWO's), and the CPOs. deck crew had 12-on 12off, IIRC. But note that the Air Wing isn't actually Ship's Crew - the wing deploys to the ship, but technically answers to the Carrier Battle Group Commodore (Who may be a Captain or Rear Admiral (LH or UH).

In any case, the USN has over 100 years of collected data on alternate (non-diurnal 24 hour) shifts. I'll see if I can find it online again. But not tonight.
The UK RN, RAN, RCN also have over 100 years of such data.

 

[Condottiere]

I think there was a recent study, which I can't remember the details, on watches and it's effects on human efficiency.

I think it's conclusions were summed up in don't wear out the crew, weary people make more mistakes, which are less tolerable with modern equipment.

 

[aramis]

I think there was a recent study, which I can't remember the details, on watches and it's effects on human efficiency.

I think it's conclusions were summed up in don't wear out the crew, weary people make more mistakes, which are less tolerable with modern equipment.

ISTR the results being tied to the new Stealth DD... as in, determining how many crew she really needed.

 

[Adam Dray]

Timekeeping and syncing might be an additional function of the xboat network.

Though synchronicity is a lie across interstellar distances--relativity and all. You can't even sync to a common event because of it.

 

[rancke]

Though synchronicity is a lie across interstellar distances--relativity and all. You can't even sync to a common event because of it.

This is presumably negated by FLT travel. If you aim at a place where a world is supposed to be in 168 hours and that world turns out to be where you expect it to be when you arrive 168 hours later, that's synchronocity enough for any practical purpose.

(Also, FLT or not, if you aim a laser at a spot one lightyear away, can the people at that spot not conclude that you sent it exactly one year earlier when they see it?)


Hans

 

[Condottiere]

I doubt that you can sync using x-boats, since your mileage and time may vary.

However, X-Boat stations may have precise instruments that are synced with universal time, which they broadcast, and allows spacecraft and grounders to adjust their chronometers.

 

[kilemall]

This is presumably negated by FLT travel. If you aim at a place where a world is supposed to be in 168 hours and that world turns out to be where you expect it to be when you arrive 168 hours later, that's synchronocity enough for any practical purpose.

(Also, FLT or not, if you aim a laser at a spot one lightyear away, can the people at that spot not conclude that you sent it exactly one year earlier when they see it?)


Hans

Two points-

1) Is the jump always 168 hours? If so, reliable Generate jump plans would put you on the 100D limit consistently. If not, the jump plan needs to have a safe zone which would potentially put the target planet several light seconds away from a shortest time jump if the jump goes long in elapsed time.

2) No you cannot assume that, light bends in heavy gravity, the speed is the same but the distance traveled relative to source emitter position may be longer.


As long as you know all the gravitational effects between here and the laser source you should be able to calc it, but its not going to be consistently exactly 1 LY distance per exactly 1 LY time.

 

[SanDragon]

Imperial Navy is on Sylean Standard Time.

 

[rancke]

1) Is the jump always 168 hours?

No. There are two different reasons for that. One is jump variation, which makes the jump take 168 +/- 10% hours. With those, if you arrive ins, say 160 hours, your target world will be where you'd expect it to be after 160 hours. So they represent no problem. The other is misjumps, which can skew time in the ship relatively to time in the universe. If they are identified as misjumps (as is usually the case), they can simply be ignored. If they not identifiable as such, the time variation must be very, very slight.

2) No you cannot assume that, light bends in heavy gravity, the speed is the same but the distance traveled relative to source emitter position may be longer.

As long as you know all the gravitational effects between here and the laser source you should be able to calc it, but its not going to be consistently exactly 1 LY distance per exactly 1 LY time.

But if you can calculate the difference that doesn't matter. You'd be able to compensate for any such variation.


Hans

 

[rancke]

Imperial Navy is on Sylean Standard Time.

More likely it is on Imperial Standard Time (which is the same as Greenwich Mean Time (presumably actually Coordinated Universal Time)). Sylea is extremely unlikely to have a day of exactly 24:00:00 hours.


Hans

 

[rancke]

However, X-Boat stations may have precise instruments that are synced with universal time, which they broadcast, and allows spacecraft and grounders to adjust their chronometers.

You still have to figure out what time it is on the X-boat station first.


Hans

 

[kilemall]

No. There are two different reasons for that. One is jump variation, which makes the jump take 168 +/- 10% hours. With those, if you arrive ins, say 160 hours, your target world will be where you'd expect it to be after 160 hours. So they represent no problem. The other is misjumps, which can skew time in the ship relatively to time in the universe. If they are identified as misjumps (as is usually the case), they can simply be ignored. If they not identifiable as such, the time variation must be very, very slight.

8 hours little?

Not counting Earth motion, just solar system motion, 8 hours is 6,624,000 kms worth of not being where you expected it, or put another way, 20+ light seconds off.

Or another other way, that's approximately 520D from Earth.

That's PLENTY of pirate match vee and plunder time, just for starters.

Heh, I already have it beat with my mechanic, but I suppose a good one would be you know how long the jump will take so the Generate compensated and set you at the 100D limit like you like.

Interesting point there, does that mean a ship with a 168 hour jump plan being chased might face a pursuing ship jumping two hours later with a 160 hour jump plan getting there ahead of the first ship?

But if you can calculate the difference that doesn't matter. You'd be able to compensate for any such variation.

IF it is known space with major variables in the path of the light source known.

Should obtain most of the time, but not always.