Hans Rancke commented on the failure of Traveller to keep up with the growth
of the universe as envisioned with respect to quantities of merchant shipping
earlier this week. Others (the Higginbothams and myself among them) have
also commented on this in the past.
(This may ramble...it's late and I'm tired---Scott Kellogg was by for dinner
tonight on his way back to Alabama). While talking with Scott about this, I
realized that I had been overlooking a resource on my shelf for a long time:
The Encyclopedia Britannica World Data Annual (1989 in this case). There
is a summary set of tables on a variety of topics, including Transportation.
Under transportation there is a section for sea cargo tonnage loaded and off-
loaded. Since this is the '89 book, I assume these figures are from somewhere
between '85 and '89. TAking three examples (China, U.S., and Bangladesh, which
are Traveller populations 9,8, and 7 respectively) we find the following
numbers:
China 71,000,000 metric tons imported (exports less)
U.S. 425,000,000 metric tons imported (exports less)
Bangladesh 7,500,000 metric tons imported (exports less)
I took the large of the two numbers, since it would put the upper limit on the
number of ships required. Assume the U.S. to be roughly analogous to an
'industrial' planet for sake of argument. Applying the standard Trav
density fudge factor of 1 ton / cubic meter, we find that 425,000,000 tons
works out to be about 31.5 million displacement tons of cargo arriving per
year. If this was all carried in bulk freighters with 20,000 tons of useful
cargo space, this would amount to 1574 arrivals per year, or 4.3 per day.
If all of these ships made one jump per two weeks (standard Trav assumption),
and shuttled between 'U.S.' and planets one jump away, a fleet of 121 bulk
freighters could handle all of the traffic. Now, if you assume that _all_
of the traffic was being carried in 400 ton Type Rs with 200 tons of useful
space, those numbers would be 100 times higher, and 12,000 Type Rs would be
needed. You can see how you would go about figuring things with the
assumptions about round trip voyage time, cargo tonnage and so forth changed,
right?
Bangladesh (free trader territory!! hehehehe) would require about 18 Type A
arrivals per day to carry all of its traffic, so the port would have about
126 ships on the ground at any given time.
Let's see, other assumptions unstated: these numbers are for tonnage by sea
only as there is no usable data on international rail and road traffic.
International air traffic is given in ton-miles (or metric ton-kilometers),
which means you need to make some guesses about trip length to calculate number
of cargo aircraft departures. Probably not significant in terms of total
volume. On the other hand, it would mostly consist of high value cargo and
might provide a different sort of estimate.
Anyway, with these sorts of real world figures available, we should be able
to come up with something that will allow us to make a reasonable guess about
ports and ships.
It's tired and I'm late...enough for now...
Rob Dean