Rather than make a bulk ship post, I will be presenting ships individually. In my treatment of Spelljamming Ships, Ships and Helms are integrated into a single magic item, and so cannot be removed from each other without a major rebuild. Unless otherwise noted, all Spelljamming Ships use the vehicle rules found on page 119 of the Dungeon Masters Guide.
So I am starting out with the Tradesman, a "standard" ship in Wildspace, and one most often acquired by adventurers.
Cargo: 18 tons
Hit Points: 625
Damage Threshold: 10
2 Cannon (crew: 2) Ranged Weapon Attack: +6 to hit, range 600/2,400 ft., one target. Hit: 44 (8d10) bludgeoning damage.
The tradesman is undoubtedly the most widely produced, widely used, and widely altered spelljamming vessel in the Cosmic Seas. Originally crafted as a small merchant ship (hence the name), the tradesman has seen use as a scouting vessel, pleasure craft, personal transport for the wealthy, and even (heavily modified) as a short-range warship. The trailing fins of the tradesman, though appearing merely decorative, help its maneuverability in flight. It raises its sails when traveling by water, relying on wind rather than its helm for propulsion.
Away from planets and other large objects, a Tradesman flies through space at what is called cruising speed. At cruising speed, a Tradesman ship allows a ship to travel between adjacent planets in 2d6+2 days (The random element assumes that even adjacent planets may be in different parts of their orbits). In extreme circumstances, you could double or even triple these times.
These vessels come equipped with two Lanterns of Air Purity and an Astrolabe. See Special Equipment for details. Any other equipment must be purchased by the owners/crew.
Trading: The trade routes to most worlds are not extensive to begin with, and most people find the solutions to trade problems afforded by magic superior to long-distance travel through space.
There are exceptions. Worlds that lack certain metals, lumber, or finished goods are often quite happy to be part of interstellar trade. And, of course, all worlds appreciate the glow of extraterrestrial gems and jewels. The most common traffic even to worlds that value magic over space travel is in information; small, valuable items; unique items; smuggling; and passenger service. In these areas the standard tradesman is at its best—a cheap way to get from point A to point B.
Free Adventuring: The tradesman is often a first-time adventurer's craft, mainly because it can be
bought cheaply and repaired easily. Aboard adventuring ships, the chain of command usually stops after captain—which in adventuring terms usually means "the one who yells the loudest." Merchant tradesmen are not particularly happy with the collection of spell-wielding and sword-swinging maniacs who trample all over their stock and trade, riling up the monsters and bringing attention to the tradesman as a ship to attack. The traders' reactions to adventurers who use these ships varies.
Some are unwilling to deal with such individuals. Other send them on wild goose chases to other systems to drive them away.
Piracy: The common nature of the tradesman also makes it a vessel for pirates new to the trade, again before they "trade up" to more impressive craft. When using a tradesman, the pirate's best targets are other tradesmen and the occasional galleon that is brought up out of the ocean by groundling adventurers. Pirates who use the same tradesman for a while tend to modify it by speeding it up, making it more maneuverable, and adding more weapons.
Light Cruiser: A tradesman variant preferred by pirates and those plagued by pirates. This type of ship
has an Armor Class of 16. It carries three cannons.