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Shipyard Production

Here's a design challenge for you:

A cubic mile of ice is about 310,000,000 dtons. Have a specially designed rig jump out to the inner oort cloud and attach to one of the many large chunks of ice floating around. Using thrusters (or conventional rockets using water as propellant) generating a few hundredths to a tenth of a G. Drive the large block of ice into orbit around your planet. Refine fuel from block of ice.

If you really are pulling a cubic mile of water off your primary world every seven years. It won't be too long before someone notices the climate change.
The Earth's surface area is 510 000 000 km2, of which 360 000 000 km2 or 360 000 000 000 000 m2 is water. The top mm of water is 360 000 000 000 000 * 0,001 = 360 000 000 000 m3 or ~25 000 000 000 dT water.

If we skim 310 000 000 dT water for fuel every year it will take us 25 000 000 000 / 310 000 000 ≈ 83 years to lower the oceans 1 mm (1/25").


No-one will notice such puny skimming, ever.

On a tiny world, with tiny oceans we might object on principle. Practically it will not matter.
 
If the typical corsair craft is four hundred tonnes, you aren't going to need anything larger than a frigate to counter that and act as trade protection.

Line of battle ships are power projection, and reflects what other interstellar polities bring to the table; if smallcraft and strikecraft are furnished with weapon systems that can critically affect larger ships, the switch will be to carriers.
 
I have a sneaking suspicion that the volume of hydrogen being used on a frequent basis would prove to be interesting.

The Earth has 360 000 000 000 000 m2 of surface water. The oceans are currently raising by about 3 mm / year. We can skim 360 000 000 000 000 * 0,003 = 1 000 000 000 000 m3 or 77 000 000 000 dT water per year without changing the surface level.

A single MdT freighter doing J-3 every other week would use 1 000 000 * 30% * 25 = 7 500 000 dT fuel / year. The Earth could support 10 000 such megaton freighters without changing the surface level.


A gas giant like Jupiter has a volume of ~1024 m3 or about 1023 dT. It would take 1 000 000 megaton freighters about 1023 / 106 / 107 = 1010 years or 10 billion years to deplete the gas giant.


Space is big. Humans are puny.
 
The Earth has 360 000 000 000 000 m2 of surface water. The oceans are currently raising by about 3 mm / year. We can skim 360 000 000 000 000 * 0,003 = 1 000 000 000 000 m3 or 77 000 000 000 dT water per year without changing the surface level.

A single MdT freighter doing J-3 every other week would use 1 000 000 * 30% * 25 = 7 500 000 dT fuel / year. The Earth could support 10 000 such megaton freighters without changing the surface level.


A gas giant like Jupiter has a volume of ~1024 m3 or about 1023 dT. It would take 1 000 000 megaton freighters about 1023 / 106 / 107 = 1010 years or 10 billion years to deplete the gas giant.



Space is big. Humans are puny.

Now look at that over a span of 100 or even 1,000 years where it comes to Earth's water supply.

Also, continued dipping into Jupiter will change its characteristics over time. I think however, that you missed my original point. Do an analysis of how many freighters are in active service for trade within a region to get the total hulls using the volume of fuel being bandied about in your post above. Then multiply that by a factor of 10 for the volume used in a decade. The numbers will likely surprise even you.
 
For anyone interested, I've resurrected the thread regarding a fueling corporation in THE LONESTAR titled as "GURPS TRAVELLER Gas Mining Operations". I will post the specs on the ships used in that "operation" and will also post the specs on the ground vehicles etc. I will try and recreate the actual spreadsheet data I used for the initial stock offering per the rules in GURPS TRAVELLER FAR TRADER.

That is so that I can stop posting to THIS thread and keep the drift to a minimum. Sorry!
 
I presume that is why GURPS TRAVELLER STARPORTS notes that some worlds with hydrographic values of 4 or less, routinely forbid or heavily regulate on world refueling. When I mentioned this once before, people were NOT happy.
Take a size 2 world with hydrographics 2. It has a diameter of 3200 km, so a radius of 1600 km and a surface of 4 * π * r2 ≈ 32 000 000 km2 or 32 000 000 000 000 m2. 20% ocean is ~6 000 000 000 000 m2 water surface.

1 mm of that water is 6 000 000 000 m3 or ~400 000 000 dT. If this is a major trade route and we skim heavily, it might even be measurable in a few decades time...

On the other hand 400 000 000 dT is about 20 000 000 Scout/Couriers refuelling. In a year that would be ~55000 a day or ~2300 an hour. Who would want that kind of traffic over prime beachfront property? Especially as they are Scouts and will create sonic bangs and crash into each other regularly?
 
I think however, that you missed my original point. Do an analysis of how many freighters are in active service for trade within a region to get the total hulls using the volume of fuel being bandied about in your post above. Then multiply that by a factor of 10 for the volume used in a decade. The numbers will likely surprise even you.
I do not have Gurps Traveller.

I can use my own amateurish estimate above:
Quick, very non-canon, estimate of trade volume:

China, pop 1.5 billion, exports about 30 million TEUs per year or about 100 million dT per year.

A 50 billion pop A world with the same ratio would export ~3000 million dT per year.
Say we are using 100 kT J-3 freighters carrying 50 000 dT cargo. We spread the exports over a subsector, say on the average 6 Pc or 2 jumps. A regular trip takes 2 × 9 + 5 = 23 days one way or 46 days round trip, that is 7,6 trips / year. So each freighter exports 50 000 × 7,6 ≈ 380 000 dT / year. We need 8000 such freighters for that volume of trade.

8000 freighters using 100 000 × 30% = 30 000 dT fuel per jump and 7,6 × 2 × 2 ≈ 30 jumps / year is 8 000 × 30 000 × 30 ≈ 7 000 000 000 dT fuel / year.

For Earth that would be 1/10 the volume we can skim without affecting the ocean surface level. And much of that would be skimmed all over the subsector.


That would be a billion dT merchant ships per subsector at a value of TCr400. That would be something like half a trillion dT merchant ship at PCr200 for the entire Imperium. The Imperium has a GDP of PCr138 according to the wiki. If we replace the shipping every 50 years that would be PCr200 / 50 = PCr4 or 3% of the Imperial economy devoted to building ships. A bit much.


(PCr = Petacredit, PCr 1 = Cr 1015 = Cr 1 000 000 000 000 000)
 
With only one trade partner, Lunion <=> Adibicci generates on average, some 30,000 dtons of freight traffic (line business) per week. Tramp freighter trade carries about 750 dtons on average.

Trade is a function of economies as a function of population. It gets modified downwards due to distances involved. A single pop 9 or 10 world can have as many as 30 trade relationships (or more). I'd have to check my text file I have that lists these relationships for the spinward marches. It was created by running every world against all other worlds, calculating distances in parsecs, adding both world trade values and subtracting distance penalties. If the bi- world trade value failed to exceed 6.5, it didn't make the list. Yearly trade volumes for a bi-world trade value of 10 results in 1 to 5 million dtons yearly.

If it were me trying to estimate shipping tonnages involved, I'd divide tonnages by .9 to account for the fact that all ships never get 100% cargo capacity filled. Then I'd get the average cargo capacity per class of ship, and use those numbers to divide weekly tonnage rates to approximate hulls involved in shipping. Yes, you have to account for the different possible class of ships in your Traveller universe when you do this. So design a few sub-1000 ton ships, a few large freighter classes, as well as a few passenger liners that might take some freight in addition to their primary core service of passenger transport. Of course, once you figure things for freight, you get to it for passengers as well. ;)
 
With only one trade partner, Lunion <=> Adibicci generates on average, some 30,000 dtons of freight traffic (line business) per week. Tramp freighter trade carries about 750 dtons on average.
Let's see what we can do with this...

Lunion has a pop of 8 billion (pop 9). I generates 30 000 dT trade / week with a single nearby pop 8 world. We can have up to 30 connections, but the further away, the less traffic.

30 000 dT / week is ~1 500 000 dT / year. We have 30 connections, but most are smaller, some are larger, let's call it 20 times that in total for a total of 30 000 000 dT / year.

Using the same 100 000 dT J-3 freighters transporting 380 000 dT / year as above, we need 30 000 000 / 380 000 ≈ 80 freighters to handle the volume.

They consume 100 000 × 30% = 30 000 dT fuel per jump and 7,6 × 2 × 2 ≈ 30 jumps / year is 80 × 30 000 × 30 ≈ 70 000 000 dT fuel / year. Peanuts.


Lunion is almost half of the subsector, so the subsector would need ~200 freighters. Since the ships carry cargo both ways it should be ~100 freighters for the subsector. At 300 subsectors the Empire would need 30 000 freighters (3 billion dT) worth ~PCr1,5. Replacing them every 50 years would cost TCr30 / year. That is 30 / 138 000 ≈ 0.02% of the Imperial economy. Certainly affordable.
 
Irrelevant real world example:

Earth today has about 1 000 000 000 GT shipping. A GT appears to be about 1/4 dT so 250 000 000 dT shipping, dominated by bulk carriers, tankers, and container ships. Passenger traffic is negligible.

The biggest ships carries 550000 dwt or 19000 TEU, both appear to be about 50 000 dT cargo.

Recalculate in to this:
450px-MSC_Oscar_%28ship%2C_2014%29_002.jpg
195000 GT ≈ 50 000 dT, external cargo 19000 TEU ≈ 50 000 dT. M$140 ≈ MCr70.

All the worlds shipping would correspond to 5000 such ships carrying 250 000 000 dT cargo. A scheduled trip China - Europe - China seems to take ~3 months, so perhaps 4 trips per year. Total trade volume 4 × 250 000 000 = 1 000 000 000 dT / year. Total cost of merchant fleet 5000 × MCr 70 = GCr350.

Compared with the estimate of Chinese export of 100 000 000 dT / year that is not entirely unreasonable.
 
Looking at the age of the fleet there appears to exist a lot of old hulls, but a negligible part of the tonnage is older than 25 years. It appears the big ships are replaced after about 20 years, but the small tramp freighters are used until they are very old.

250 000 000 dT of shipping is replaced every 20 years, means a used shipyard capacity of 250 000 000 / 20 = 12 500 000 dT turning over GCr350 / 20 = GCr17,5. World GDP is ~T$80 ≈ TCr40. Shipbuilding costs 17,5 / 80 000 ≈ 0,02% of the world economy.

TCS says it should be about 7 000 000 000 / 1 000 ≈ 7 000 000 dT. Not unreasonable.
 
That's because ship systems and hulls decay, and it's easier to build a new ship.

Also, maintenance costs in Traveller are incredibly and fractionally cheap.
 
While those are all interesting in terms of global trade, the question is how much of that will translate in to actual interstellar trade.

I don't know what fraction of the global trade is in, say, petroleum, but that's perhaps an example of a staple commodity that most planets would like to keep local if possible.

I'm simply using petroleum as a base example of a staple commodity that folks would be motivated to keep local if only to keep costs down.

But it also brings up other freight costs.

Is a M-Drive equipped ship the cheapest form of transportation available? Would worlds still float large holes in the water to put stuff in to in order to move goods from one end of the planet to another? How much cheaper is the hull of a large container ship than a star ship? How much cheaper than a ship designed not to float, but not leave atmosphere either. Ideally the structural aspects of a floating ship supported by water are less than a free standing ship. The time benefits of flight may simply not warrant the extra expense of building the craft.

But all those factor in to how much trade and commodity development remains local to the planet rather than relying on imports. Logically I'd think there is great value to keeping such staples local (not simply for security, just raw economics).

That just suggests that as the world gets more mature, it will rely more on what it can produce locally than on imports. Relegating interstellar trade to more exotic and luxury items.

So, while these numbers of global shipping are representative of total trade currently on Earth, I don't think those numbers necessarily translate 1:1 to an interstellar system.

But "I am not an economist", and the Imperium's economy is lightly sketched out at best anyway.
 
While those are all interesting in terms of global trade, the question is how much of that will translate in to actual interstellar trade.
There is, of course, no reason to believe that todays wet shipping has anything to do with space shipping 3000 years from now. But it says something about the economy, we can't devote even 1% of the Imperial economy to building merchant shipping without extraordinary explanations. That caps merchant shipping in the Imperium to a few billion dT, or perhaps max 10 billion dT. That leads to a used civilian shipyard capacity of perhaps in the region of 500 million dT in the entire Imperium and that means shipyard with a capacity over 1 million dT will be rare.


A) The collection of Naval bases should have a "Port capacity" large enough to support the Imperial navy in the area. Generally this is a subsector. Based upon calculations done by Chris Thrash and Hans the Imperial subsector navy (Numbered Fleet) is between 10 and 30 million Dtons.
From this we can roughly estimate the entire Imperial Navy to also about 10 billion dT using another 500 million dT yard capacity.


If each ship is big and takes a few years to build then the entire Imperium is using something like 3 × 500 million × 2 ≈ 3 billion dT yard capacity.

That is a value that is vaguely estimated from canon, and is of course not very exact. But you would need a good argument if you want the number to be more than 10 times bigger or smaller.

We can also see that the TCS formula that would give us a yard capacity of ~pop/1000 or 18 trillion / 1000 ≈ 18 billion dT is about ten times too much.
 
But all those factor in to how much trade and commodity development remains local to the planet rather than relying on imports. Logically I'd think there is great value to keeping such staples local (not simply for security, just raw economics).

That just suggests that as the world gets more mature, it will rely more on what it can produce locally than on imports. Relegating interstellar trade to more exotic and luxury items.
You may be right but I believe not.

In our history lasting peace generally leads to increased specialisation and increased trade, and there are very good economic reasons for that. Today we call it globalisation. In short, there are no good reasons for putting a microprocessor fab or umbrella factory in every city or every country.

Most of the Imperium has had internal peace for 500 years or so, nothing has interrupted trade routes for these centuries.

Interstellar shipping is very cheap. Using a large J-3 freighter we can push prices down to a few hundred Cr per Pc, even faster and cheaper with drop tanks. Let's say a megacorp can ship a dT on a major trade route for Cr500.

To ship a TEU container between Europe and China seems to cost a few hundred $, probably cheaper in quantity, let's say Cr100 or Cr35 / dT. Interstellar shipping is much more expensive than ocean transport today. Cheap bulk goods would be expensive to ship.

Trade to the next sector, say 50 Pc, starts go get expensive.

Example: Industrial goods:
A hand-computer (iPad) costs Cr1000 and weigh 0,5 kg. The packaging might be 0,0025 m3 or 400 / m3 (actual iPad carton measured), a dT is 14 m3 or 5600 units. To ship a dT to the next subsector (10 Pc) would cost Cr5000. The computers sell for ~5000 × Cr1000 ≈ Cr5 000 000. Shipping would be 0.1% of the price.

Example: Food:
A bottle of wine sells for Cr10. A bottle is 0,75l or 18 000 per dT, we lose space when shipping cylinders, so let's say 10 000 bottles per dT. They sell for 10 000 × Cr10 ≈ Cr 100 000. Shipping is still Cr5000. That is 5%, clearly noticeable, but not crippling. You are still likely to pay more for local delivery than interstellar shipping.
 
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For what it is worth, I dug up a data file I created that listed all of Lunion's BTN trade partners where the BTN value was 6.5 or higher. 6.5 BTN means VERY minimal trade going on - the kind that can be fulfilled by a scout ship. The higher the value, the more trade obviously.

Lunion's BTN list where BTN > 6 amounts to 321 trade partners.

Breakdown was:

52 X 6.5 BTN Trade Partners
70 X 7 BTN Trade Partners
88 X 7.5 BTN Trade Partners
52 X 8 BTN Trade Partners
29 X 8.5 BTN Trade Partners
18 X 9 BTN Trade Partners
8 X 9.5 BTN Trade Partners
4 X 10 BTN Trade Partners


Will give you average tonnage per BTN Value when I get a chance later.
 
Then there's training, another factor that's hard to stuff into a spreadsheet macro. Yeah, during WW2 the USN was able to take hillbillies and turn them into radiomen and radar operators, but what was the TL "gap" in question? One or two? Are you going to take a kid from a TL 4, 5, or 6 world and train him in a reasonable amount of time to operate, maintain, and repair TL 14 and 15 equipment?

Say, what happened to that 'monkey see monkey do' mixed TL ethos you were pushing?

Surely the intrepid TL jumping weather crystal radio operators of the lower TLs can be brought up to speed.
 
Don't forget that the Traveller starships are the airliners and spaceships the in-system 'trains' re: passenger transport and rapid cargo/mail/parcel delivery, so that is a significant amount of tonnage to build and maintain.
 
True, that is something we have ignored so far.

It is also rather difficult to even begin to estimate. Does Gurps have any clues?

It would give B starports something to do...
 
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