10% of your cargo at any one time

[locarno24]

Quick question relating to cargo hatches:

According to the rules

Ships with cargo space have cargo hatches, allowing up to 10% of their cargo to be transferred at any time.

I was wondering how long 'at any time' is? The reason I ask is that I've got a statline for a 'flat pack' missile pod that a military cargo ship can load, but for it to be useful, I need to know at what rate they can be cranked out of a cargo bay.

Assuming that the freighter is a pretty huge bulk supply ship - call it 250 dTons of cargo space - then it supposedly has enough room in its hatches to easily handle multiple 'Sixgun' pods, which I make to be about 4.5 dTons, simultaneously. However, whilst it can ship five pods through simultaneously, that doesn't mean it can drop five every 6 minutes. What I can't see is any guidance on how long it takes to dump a dTon of cargo in zero-g.

Obviously you couldn't be manouvring or evading as you did so, and it'd depend what cargo-handling gear is fitted. I'm just looking for a starting point - apologies if I've overlooked something somewhere...

 

[DFW]

I was wondering how long 'at any time' is?

Read, "at a time"

 

[locarno24]

The 10% is how much can be shipped through the hatches at once; it's defining the size/number of hatches (which is why it's in the Airlocks section)

The process of shipping it through those hatches will not be instantaneous when you're talking tens or even hundreds of dTons of cargo, and even if it's a short enough time not to matter in normal ship operations it will certainly be long enough to matter in combat. Does moving a chunk of cargo equal to that hatch capacity through said hatches take 1 minute? 6? 30?

That's what I'm after any reference on.

Airlocks are supposed to take 10 seconds to cycle but claiming that you can unload your hatches' capacity every ten seconds means that in a standard combat round you'll cycle them 36 times, meaning that your entire cargo load can be dumped in 1/3 of a round. That sounds unrealistic to say the least.

 

[DFW]

Does moving a chunk of cargo equal to that hatch capacity through said hatches take 1 minute? 6? 30? That's what I'm after any reference on.

Just go down to the local airport. It takes about 20 seconds with the correct cargo handling equip and in gravity (which makes it faster).

 

[rust]

GURPS Traveller - Far Trader has data on unloading cargo on page 58.

According to this, a merchant vessel can under normal conditions unload
30 dtons of breakbulk, 120 dtons of RO/RO cargo, 180 dtons of containers,
360 dtons of dry bulk goods or 540 dtons of liquid bulk goods per hour.

Also according to Far Trader, these values are constrained by freight-han-
dling techniques, the availability of marshalling areas, the contact area
between ship and berth, etc., but not much by the actual size of the ship.

In my view your missile pods would be somewhat like RO/RO cargo, so
120 dtons per hour = 2 dtons per minute would seem reasonable to me.

 

[locarno24]

GURPS Traveller - Far Trader has data on unloading cargo on page 58.

According to this, a merchant vessel can under normal conditions unload
30 dtons of breakbulk, 120 dtons of RO/RO cargo, 180 dtons of containers,
360 dtons of dry bulk goods or 540 dtons of liquid bulk goods per hour.

Thank you, sir, that's exactly the sort of thing I was looking for.

So without specifically rebuilding the ship for the task, 12 dTons worth of cargo per round sounds reasonable with the example you've given. Marshalling isn't so much of an issue - we're talking 'heave it over the side', but the freight-handling will be only the ship's internal stuff, so it probably works out even.

...Right. So ~ three of the basic 'sixgun' missile pods (4.5 dTons) or two 'sawn-off' heavy missile pods (7 dTons) a turn, provided you've got cargo space capable of handling that much simultaneously (i.e. 150 dTons or so assigned cargo space). Sounds fair enough.

That works out at 18 missiles/4 torpedo batches - somewhere between a bay and a heavy bay - albeit at a much, much higher cost and with the ability to dump pods for several rounds then mass launch them for those 'barrage of egregious ordnance death' moments.

 

[zero]

Meh, I assumed there'd be some automation and though a cargo-bay door counted as a ship's airlock for the limit, that is was a little different due to its cargo specialty.

A current ship I have planned at 200tons has a standard airlock and on the below deck where cargo is, the cargo door for its 2 airlocks (1 per 100 tons).

 

[omegar]

120 dTons. Per hour can be done because RO/RO Invloves goods in standardised sizes, this is going to be bigger than 2 dTons. It is a system with high latency I suppose, there would be whole minutes where nothing is moved, and then a huge chuck would be moved.

I think that it would be in a set number of chunks of 10dTons, or
Even 20 dTons.

 

[Captain Jonah]

With Traveller standard shipping containers the vast majority of stuff is going to be containers.

At 10% of total cargo every turn thats an hour to offload everything which is probably slow for a high tech starport with grav lifters and robotic cargo handlers.

As Zero said, multiple cargo doors allowing two or three teams to load/unload larger ships at once.

Rating cargo shifting by 10% of the ships capacity is probably better than the gurps way unless gurps numbers are treated as per door. A fixed limit per hour regardless of ships size means unloading a megafrieghter of 50,000 dtons of cargo would take over 11 days.

Merchant prince page 114 the cargo handling system. Oddly this gives figures in terms of man hours of work it does without anywhere ever explaining how many man hours per hour are used.

For your podnaught design. Use 10% of total cargo rather than the gurps fixed values, a big warship dropping less than a score of extra missiles by pod just isn't going to be worth it. Dropping hundreds will be noticed

Try.
Have Starship, will Traveller 6

Cargo Transfer.

STARPORT CLASS......TONS PER 6 MIN........MAXIMUM / MIN
A..............................10% of ships cargo.....Unlimited
B..............................10% of ships cargo.....1500/750
C..............................5% of ships cargo.......500/250
D..............................6 x 10.........................----
E..............................D6 x 5.........................----
X..............................Not possible................----

Cargo transfer either onto of off a ship is based on a % of total capacity of advanced starports with automated cargo handling. On less advanced starports cargo transfer is based on having a cargo vehicle available to move the cargo containers around. Maximum cargo is in tons per hour for a single standard docking bay, minimum is the tons per hour the system can handle even on smaller ships. Use minimum where % of cargo hold is smaller otherwise use % of cargo hold up to maximum. A Class A or B starport can empty a medium merchant ship in an hour or two, time is money after all.
A class A starport is capable of moving tens of thousands of tons of cargo an hour though if they have a 500k ton megafreighter in port you may have to wait a few hours before they can get to your ship so it is refs discretion as to how quickly you can get unloaded at the commercial docking bays. Class B and C starports are more restricted in what they can move on or off a single ship. Class D and E starports rely on vehicles and are limited by the number and capacity of the vehicles. Class X starports being no more than flat areas of ground with a landing beacon have no cargo handling and require either hand unloading or the Ship must bring its own cargo handling vehicle or device.
A ship equipped with a cargo handling systemwill have no effect on the cargo transfer rates of class A, B or C starports. On the others it will count the starport type as one level higher for cargo transfer rates so a ship with a loading belt and 200 tons of cargo docked at a class D starport will be able to load and unload at the rate of 200 tons an hour as that is the minimum for a class C port.

 

[phavoc]

One thing to keep in mind is that if you are ejecting a missile pod, you are basically tossing it out, and probably giving it a big of a 'shove' to clear the ship. Then (assuming here) onboard gyros and thrusters are going to orient the pod towards your target and then launch can occur at any time after that.

So standard loading/unloading rules don't apply. If you only care about getting it outside the ship, you don't need to worry about niceities like making sure you don't bang it up too much, or jarring it or whatever. As long as it makes it out the hatch and clears the ship you're good.

A good analogy would be how long does it take you to clear out your closet? If you are just chucking everything out and not caring how neat it is outside the door, then you'll clear it out in probably a 1/10th the time if you had to take everything out, move it, stack it neatly, then return to the closet.

You should be able to chuck out a pod at least every 30 seconds if you have mechanical help, like a track-system that the pods roll along and then get shoved/ejected. If you want easy math, then make it every 60 seconds, which gives you a ROF of 6/combat turn. And size really wouldn't matter, so missile or torp pod would be treated the same.

 

[rinku]

The "hour to unload" implied by 10% per turn does make sense if you are talking about the entire process (i.e. unloaded, receipted, sorted and stored). You can only unload a quickly as the recipient is able to cope with it.

 

[locarno24]

So standard loading/unloading rules don't apply. If you only care about getting it outside the ship, you don't need to worry about niceities like making sure you don't bang it up too much, or jarring it or whatever. As long as it makes it out the hatch and clears the ship you're good.

A good analogy would be how long does it take you to clear out your closet? If you are just chucking everything out and not caring how neat it is outside the door, then you'll clear it out in probably a 1/10th the time if you had to take everything out, move it, stack it neatly, then return to the closet.

Believe me, you are not 'chucking them out'. When you're moving large amounts of ordnance about, inside a ship's armour belt, whilst potentially under fire, you do it bloody carefully. Whilst it may fall freely once it's out, I'd guess it balances out with the time for moving things inside the holds.

 

[zero]

^ That.

Also in my custom ship, the cargo hold is for 60 tons, that makes 6 tons at max. at a time through the one cargo bay door I have. I see the regular airlock time for that be taken through what with whatever automated things move the cargo along (Probably some kind of conveyor belt with ramp is implemented).

 

[phavoc]

So standard loading/unloading rules don't apply. If you only care about getting it outside the ship, you don't need to worry about niceities like making sure you don't bang it up too much, or jarring it or whatever. As long as it makes it out the hatch and clears the ship you're good.

A good analogy would be how long does it take you to clear out your closet? If you are just chucking everything out and not caring how neat it is outside the door, then you'll clear it out in probably a 1/10th the time if you had to take everything out, move it, stack it neatly, then return to the closet.

Believe me, you are not 'chucking them out'. When you're moving large amounts of ordnance about, inside a ship's armour belt, whilst potentially under fire, you do it bloody carefully. Whilst it may fall freely once it's out, I'd guess it balances out with the time for moving things inside the holds.

Let me rephrase that.... You are, essentially "chucking them out" in the sense that your goal is to eject them as fast (and safe) as you can. Obviously you are going to need a loading/feed mechanism to move the pods from their storage area to their launch area. And when they get there you will be ejecting them in such a way that maximizes your throw weight in the least amount of time.

Unloading/launching is always going to be far easier and less time consuming than loading. Plus a weapons feed mechanism is going to be optimized to unload/feed far faster than it takes to load for the simple reason that when you are feeding, you are in combat.