Anyone know of a good book, supplement, or source on ship building/design, trading? I don't know if any of you have played Traveler (I'll bet some have) but I want a system to trade/buy, sell, design, create and build your own river and sea vessels in the same basic way as Traveler did for spaceships. So ship specification and individualization will be very important in this milieu.
There are a few books covering ships, but most of those I'm familiar with have already been suggested.
For trading, if you can find them there were two GAZ-series D&D products from the late 80s, Republic of Darokin and Minrothad Guilds, which had rules for trade suited for D&D. Including, iirc, a trader class. It included a map of the region with indications of what sort of products areas exported and what they imported, rules for what ships and wagons could carry and how much they cost to operate, and most of the things you'd want for trading endeavours. My players never took an interest so I can't really tell you how they worked, and of course they're hard to obtain now.