I actually just realized that there is a really useful real-world
example of the kind of "ladder of trade" model I'm advocating.

The Port of Los Angeles / Long Beach is one of the busiest cargo
shipping hubs in the world. At any given time you'll see many
extremely large container ships (and other types of large freighters)
being loaded and unloaded. There are also pipe-head moorings farther
offshore for oil tankers. The big ship traffic goes to and from the
port via well-constrained paths, and smaller craft avoid those paths
when they can, or travel with caution when they can't.

About 40km from Long Beach lies the island of Santa Catalina. The only
significant town on the island is Avalon, which is a resort community
with lots of hotels and restaurants. It has a good marina with a pier
that reaches relatively deep water. Several supply boats arrive early
each morning with fresh food (and other necessities) for the day.

At the other end of Catalina is the very small settlement of Two
Harbors, with a year-round population of a few dozen, and a small
marina with a short, shallow-water pier. I don't know if this is still
going on, but when I spent a lot of time there circa 1990, I was
delighted to discover that they had a converted WWII tank landing
craft nicknamed the "Salad Bowl". It spent most of its time at anchor
out in the harbor, but once a week it would come to the beach, deploy
its ramp, and the town garbage truck and a large panel truck would
drive on. The boat would then cross to Long Beach, where the trash
would be disposed of and the panel truck would be loaded with supplies
for the following week. The boat would then land on the beach again,
the vehicles would drive off, and the boat would go back to its
mooring. All of this just across the channel from one of the world's
busiest cargo ports.

If there's room for three coexisting levels of shipping in a 40km
region of one planet, imagine how many there are in the Third
Imperium!

On Wed, Aug 27, 2014 at 1:52 PM, Andrew Long <andrew.long@mac.com> wrote:
> On 27 Aug 2014, at 21:10, Craig Berry wrote:
>>
>> Are people seeing my posts on this thread? Nobody has replied directly to anything I've said over the past several of them. I don't mind being ignored by people, but I'd like to make sure I'm not being ignored by a robot and hence not heard by the people. :)
>
> You're not being ignored (at least, not by me!) It's the <italic>contentious</italic> people who are generating the traffic.
>
> Regards, Andy
>
>
> --
> Andrew Long
> Andrew dot Long at Mac dot com
>
>
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--
Craig Berry (http://google.com/+CraigBerry)
"Eternity is in love with the productions of time." - William Blake