[Southernap]

So if you assume that 2300AD is canon for follow on. Then per the Earth/Cybertech source book and the Adventurer's Guide of the Core Rules, then post Twilight War, the only two nations that still had any worthy merchant fleets is the Japanese and the French. Assume that the Japanese have enough super tankers for their economy. Then they might still be willing to trade troop transport on a super tanker to protect the ship from hostile pirates in places like Bangkok (here is an entry point into Bangkok Source Book) or the Malacca straits. That can provide the fuel coming into and out of the West Coast of the North America as well in exchange for food stuffs and some light industrial goods.

I could even see some smaller style oil tankers making runs to the Lands down under again in exchange for foodstuff and some trade goods.

I also want to say that there is a Challenge article, near the end of that magazine's run, which had a Twilight 2000 scenario that mentioned the use of a Japanese merchant ship to get into Japan and rescue some rocket scientists from a town going into anarchy and bring those scientists to the US to restart the space program in the US.

So those two data points just screams to me that Japan has the best merchant fleet and more than likely in the period from 2001 till 2101 become a major economic power house/trade house in the post war period and even more so under the French Peace period.