The primary sourcebook I’m using is an ebayed copy of Mage: Sorcerer’s Crusade, a stand-alone Mage game set in 1450. I figure moving it 200 years into the future will require some adjustments, but the basic rules are fine.
These rules don’t require coincidental magic as long as the mage is using a recognizeable magical tradition, given the high belief in magic at the time. I’m thinking that in Europe, this is starting to be replaced by the modern Mage rules for coincidental magic by the 1670s, but that in the Americas, it might not be.
Ship-to-ship combat is a difficult question. The range of most combat will provide some limitations, as will the size of ships: doing serious damage to a ship will be pretty difficult (but not impossible). I’d like for mages to each be about as powerful as a big old cannon, albeit much more flexible: a ship with a cabal aboard SHOULD present a nasty threat. Of course, mages are imminently killable, and they’ll be the first ones targeted by snipers atop masts, and the need for mages to be enacting ritual motions to complete their spells (none of this coincidental nonsense back in the seventeenth century!) will make them visible targets.
I played with the idea of having salt water “ground” magic, making ship-to-ship spellcasting very difficult, but that sounds like a real buzzkill. Instead I think I’ll just set up soak rules for ships that make ships pretty tough.
So, basic outline:
-Through some hook or another, depending on PC backgrounds, the cabal ends up in Seville in September as la flota hoves into view. This is the flotilla of galleons and their guardians, carrying the treasure of the New World. Seville has a festival around this time (I assume–can’t find historical verification, but it seems really likely that such an influx of wealth and horny sailors would lead to a festival), so the game will begin in citified chaotic fun.
-One of the items aboard a ship is a root/section of an exotic orchid. Really, really exotic, supercharged with magical energies. PCs will scheme, plot, and fight to get it away from the science mages who want to classify it and study it and thereby rob its power for themselves.
-The PCs will eventually make off with the orchid for their own magical stronghold, where their mentors will begin its study deep in the stronghold’s labs.
-The science mages, having followed them back to the stronghold, will attack. PCs will be sent to defend the labs at all costs.
-The orchid, now in a location of strong magical power, comes alive, growing at a tremendous and violent rate, taking over the lab, PCs inside, and turning it into a jungle.
-By the time the PCs hack their way free of the jungle lab, they’ll find themselves under the Caribbean sky, on an island. Nearby, a band of pirates has landed and are on the verge of open violence in a dispute about shares of plunder…
The first few sessions may be somewhat railroady, to get them to the Caribbean, but once they’re there, I plan to make it a lot more open.
Oh, and Doc, virtually all the Science Mages are like the Sons of Ether in this time period, IMO. Da Vinci is major major inspiration for them. At some point they’ll be attacked by a rocket-launcher-wielding science mage flying after them using an ornithopter harness.