General Starport traffic levels -Has anyone developed an app or spreadsheet for this?

[Commander Truestar]

So, I was wondering....

Has anyone developed a spreadsheet or app for this?
I checked in the files section but I can spend a day searching all the past entries there.

Thanks for ay help

 

[Commander Truestar]

As an example, I am fleshing out the Extolay system in the Spinward Marches.

This system is admittedly on a frontier edge of the Imperium

But,
1) It is on a major trade route
2) It is on the communications/X-boat route between Regina and Rhylanor
3) It has an Imperial Naval base present
4) It is only 2 parsecs from Regina
5) It is the closest system to the Tionale system, which is an Imperial Client state
6) It is within J-6 of 10 extra-Imperial systems which may use it as an entry/trading point

So, I would expect it to have a decent traffic load.
But, using the math in "From Jump-Point to Port" by Leroy W. Guatney (GDW-JTAS 22), I get a maximum capacity of 84 Starships spread over a likely pair of highports and a downport.

That seems a bit light to me.

 

[tjoneslo]

Ohh, I have this data. I have used the GT:Far trader rules to generate the complete trade maps for all the worlds across the imperium, and indeed charted space.

The map is here:

https://wiki.travellerrpg.com/File:Spinward_Marches_Sector.pdf

The complete economic data is here:

https://wiki.travellerrpg.com/Spinward_Marches_Sector/economic/Milieu_1116

And this is the explanations of the map and the data columns:
https://wiki.travellerrpg.com/Trade_Map_Key


For Extolay itself: It has a per-captia income of Cr3,660 which make it pretty poor, but supports a trade of BCr809 / year (BCr 15 / week), and 786,930 passengers / year (15,133 per week). .

The port is self is size 4 (a medium class B port) employing 2,835 people full time.

 

[Commander Truestar]

Thank you tjoneslo
I can certainly use data such as the port employment numbers!

But, I don't see where this gives me the number of berths the ports have and the actual number of ships which might in in port at any given time?

 

[tjoneslo]

That ends up being derived from the trade routes on the map (a green BTN 10 route into Extolay):

The green lines represent BTN-10 intermediate routes. These routes are served by twenty to forty freighters and a smaller number of liners and free traders. On average ten ships per day enter or leave port. As an average there is 100,000 dtons of cargo and 2,000 passengers per week along the route.

The passenger count is higher than average because it connects to Regina, the Subsector capital.

 

[Fovean]

Thank you tjoneslo
I can certainly use data such as the port employment numbers!

But, I don't see where this gives me the number of berths the ports have and the actual number of ships which might in in port at any given time?

I think you’ll have to break it down based on the ships in YTU. If you’re just using Subsidized Liners and Free Traders, each ships is probably carrying 5-20 passengers, let’s say average 15. That’s 1000 ships per week. If you have 5000 ton haulers (or bigger) clearly there will be fewer ships per week to service those 15K passengers.

Same with cargo and freight. Rates for this cover quite a range but maybe for a quick estimate we say the average value is Cr25,000 per ton (to allow for bulk foodstuffs but also air/rafts and radioactives and so forth). At BCr15 per week that could be 600,000 tons of cargo per week. Here’s where those 5000 ton bulk haulers really come into play.

Of course YMMV. When you get into trade numbers like this I think you start to quantify the Megacorp shipping that we always hear about in the background of the 3I. I’d say there’s quite a few 10K dton mega haulers on the Extolay route, several dozen 5K dton Bk2 style freighters and liners, and scads of 200-1000 dton player type ships picking up the scraps. I’d think there’s a least 100 berths (something like 10 mega berths, 30 large berths and 60 standard berths) at Extolay Highport, if not more. And none of this “week in port looking for cargo/pax” - I’ll bet there’s some fast turnaround happening there.

EDIT: whoops, I see tjoneslo has clarified for you

 

[tjoneslo]

I'm off by three orders for the cargo. Should be Mcr 809 per year.

 

[AnotherDilbert]

For Extolay itself: It has a per-captia income of Cr3,660 which make it pretty poor, but supports a trade of BCr809 / year (BCr 15 / week), and 786,930 passengers / year (15,133 per week). .

The dominating trade route is Regina (BTN 9.5, GCr 5-10/year):

There are also a few BTN 9.0 routes, e.g. to Efate, Allel, Jenghe, and Rhylanor.


In total I get (just counting a few sectors):

So, about 7 million Dt cargo worth GCr 70 and 700 000 passengers per year.

If we bother to add all sectors it will be a few GCr more, but nowhere near GCr 800, at least locally?


The Extolay starport will handle roughly 150 kDt cargo per week, with perhaps 1-2 kDt cargo per day for free traders. That would mean very roughly tens of multi kDt freighters per week and tens of free traders per day.


700 000 passengers, of which 250 000 to Regina, means about 1 900 passengers per day, so several multi-kDt liners per day, mostly to Regina.


This is just local traffic. More traffic will be passing through.


Spreadsheet:
http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=41477

 

[AnotherDilbert]

I'm off by three orders for the cargo. Should be Mcr 809 per year.

I suspect not, but perhaps one order of magnitude?

 

[BackworldTraveller]

The UK (That's probably a TL-8 Class B shipping port) moves about 60 million TEU worth of cargo internally and about 10 million TEU through its ports each year (5 million in, 5 million out) That is a population 7 island.

Each TEU is about 5 dTons of cargo. So that's 50 million dTons

Additionally it moves about 93 million tons of dry-bulk, 192 million tons of liquid bulk and 104 million tons of roll-on-roll-off goods through its ports each year. Divide those by about 20 for dTons you get 5 million, 9million and 5million additional dTons of movements annually.

Based on the above statistics, I'd suggest that the traffic volumes at ports is considerably understated in the statistics given. It would suggest that each and every person on a planet would move about 1 dTon through the port each year.

So a population 10 world will be looking to move about 10 million 10 dTon containers through its ports each day.

i.e. Population number -3 is about the total trade demand per day in 10 dTon cargo units.

What does this tell me?
1) Worlds with populations larger than about 7 cannot have only one starport. A population value of 7 is going to generate 10000 cargo movements per day through the port perimeter. That's the equivalent of 100 trains or 10,000 lorries. It doesn't matter what type of transport is used, that's a traffic management headache.
2) For larger worlds, published starport designs have seriously under-estimated the volumes of container storage and marshalling needed. The port is going to need space for at least twice the number of containers as its daily throughput. That's 5000 stacks 4 high (or 300m x 4500m with no gaps) minimum for a pop. 7 world.
3) There are lots of big container ships about. Many more than I'd realised! A 2000 container vessel would need to be about 40,000dTons.
4) ACS cargo rules really are just picking up the last-minute trade on big worlds. Scheduled routes are a lot more reliable than that.
5) A 400 dTon pirate ship is too small or most civil shipping is really unarmed: Your average Traveller's floating gunboats are the exception not the rule and are definitely at the dodgy end of acceptable in civilised areas.
6) The only thing that will provide trade to satisfy a pop 10 world is a pop 10 world...Those major trade routes are huge and distance isn't really an issue.

 

[Condottiere]

1. Then you have Just In Time.

2. And three dee local printing.

3. Recycling might be encouraged.

 

[Commander Truestar]

The Extolay starport will handle roughly 150 kDt cargo per week, with perhaps 1-2 kDt cargo per day for free traders. That would mean very roughly tens of multi kDt freighters per week and tens of free traders per day.

700 000 passengers, of which 250 000 to Regina, means about 1 900 passengers per day, so several multi-kDt liners per day, mostly to Regina.

This is just local traffic. More traffic will be passing through.

Per Canon, we also know that the following corporations/MegaCorps are active in-system:
Al Morai - Transport
Uakye Trans. Partners - Transport
Hawkins & Ouzogh LIC - arms salvage org, recovering/refitting Zhodani, Sword Worlds &
Vargr gear left from the 5FW
Oberlindes -Transport

We also know, from location, that there should be a significant amount of cross border trade with extra-Imperial systems nearby. Those systems will largely use the ports at Denotam and Extolay as entry ports unless they have the political or economic clout to jump the additional systems to reach Regina directly

 

[AnotherDilbert]

We also know, from location, that there should be a significant amount of cross border trade with extra-Imperial systems nearby.

There is some according to the Far Trader system:

About the same trade to Arden as Vilis, but far less than Regina.

 

[Hairy Jim DeGriz]

I'd like some more data, please

Ohh, I have this data. I have used the GT:Far trader rules to generate the complete trade maps for all the worlds across the imperium, and indeed charted space.

Looks like another trip to FFE to purchase the GURPS starship CDs for MTU reference. So Far I've purchased the T5, T4 and d20 CDs. I refuse to buy the LBB collections since I still have my original books....

Three questions - Have you posted any other subsectors (like Glimmerdrift), and how do I find them? Are Excel files avaialble? What RU formula did you use so that there are there no worlds with negative RU when Efficiency is negative?

 

[Commander Truestar]

I refuse to buy the LBB collections since I still have my original books....

I bought that for two reasons:
1) the added out-takes and "change over time" comparisons
2) I transferred all the files to an external HDD and it makes it soooo much easier to reference the books during play as a GM

 

[AnotherDilbert]

Spreadsheet for the entire Imperium (with surrounding sectors).

Type a system name, get total trade:

Spreadsheet link:
http://www.travellerrpg.com/CotI/Discuss/showpost.php?p=626185&postcount=4