I realize the earlier pic I gave of the Civilization IV technologies is impossible to read – that is a problem with blogspot, that won’t let a decently large picture get posted in high definition. I include the following pic, a portion of the table, to give an overview.
Moving on ...
The first cultures to devise boats were those whose primary purpose was getting at the fish or waterfowl dwelling on or in rivers. Such craft were small, were propelled by poles or paddles, and were not especially seaworthy. Craft of this sort would reach its peak with the canoe of North America or the outrigger of the Pacific Islands – but until 3000 years ago, such boats were intended for hunting and not for travel.
The larger sailing craft has its beginnings in deltas – specifically the Nile and lower Mesopotamia. It is logical, is it not? A watery environment requires shipping as part of the transportation/haulage of an agricultural community – hunting communities have less reason to haul goods. Add to that the yearly flooding of deltas, where travel by water is the only means possible. The flooding current demands that larger cargo vessels be somehow outfitted with superior motive power in order to keep from being washed out to sea.
The river provides a natural trade route – as does immediate access to the sea. The rule has often been that the combination focuses culture. Larger, seaworthy ships are developed, enabling them to stand up against storms – though generally the ships were built with shallow keels, allowing them to be beached when weather threatened. The galley is the high point of development for a thousand years ... up until the 3rd century CE.
Ships in D&D are usually depicted being at sea for days at a time, whereas in ancient Greece ships were almost always pulled up on the beach at the end of each day. Oarsmen were never slaves, not even in the Roman era. This was a Hollywood fiction. Oarsmen eat, and are stronger when fed well – in combat, slaves chained to oars are rather useless when the ship is boarded – whereas free, paid oarsmen fight very well. Why would you spend money to support men who could not defend the ship – nor have a reason to – when the ship is attacked?
In most galleys the oarsmen sat open to the sky – the sort of galley typically portrayed in the 1950s in Hercules epics. Hollywood movies of a later date (beginning with Ben Hur) will usually show the ‘cataphract’ variety, where a deck has been built above the rowers. Such ships were phenomenally expensive, could not be easily beached, and were thus strictly the province of the military, to be used only in battle and only with the expectation that the weather be damned. They were not used for trade or ordinary sea travel, since in a storm they were virtually certain to sink.
I have always had a soft spot for seagoing campaigns. By and large my players over the years have been less than interested. The ships are too expensive, the battles too long and clumsy. If ever there was an argument that plunder was not the soul of the game, its the lack of interest I’ve had in the art of pirating. Part of that, it has been explained to me, is the near certainty of death once the ship goes down. That tends to turn players off.
This also explains why no useful rules have ever been written regarding waterborne combat, travel or ship design. If I had a party bent on it, I would take a few months expanding the basic rules from Trireme and Wooden Ships and Iron Men, build into it some kind of damage system based on the principles of Starfleet Battles.
For this post, I’ll simply point out that every highly developed technological culture had sailing as its most powerful military arm. The Phoenicians, the Athenians, the Byzantines, the Venetians and Genoans, the Dutch, the British and finally the Americans.
Any culture on your world that does not have a strong navy will inevitably be inward looking, in its art, in its politics and in its suspicion of strangers. Waterfronts have the habit of being very open to foreigners – inland, not so much. You can measure the hatred for wandering adventures in direct proportion to how far they wander from sea and river ports.