There are four ship types in Patrician 3: Snaikka, Crayer, Cog and Hulk.
Snaikkas are fast, highly manoeuvrable and very cheap, but they can hold very little cargo. Crayers have average manoeuvrability and are quite expensive. (A highly manoeuvrable ship is more able to avoid hazards such as storms while travelling and can be turned more easily in naval combat).
Only Snaikkas and Crayers can sail up rivers, which makes them necessary for trading with the towns of Cologne, Torun and Novgorod.
Cogs are more manoeuvrable, larger and slightly cheaper than Crayers, though they are slower. Hulks, though unresponsive, can carry very large amounts of cargo, cannons and sailors. Both types of ship can withstand substantial damage, a useful trait for warships or expedition convoys.
Hulks can only be built by experienced shipyards, and they are generally not available in the beginning of the game (unless you start in year 1380 or later). Pirates gain access to Hulks much earlier, so it is possible to capture Hulks before they can be built at a shipyard.
Experienced shipyards build improved ships, which have higher cargo capacity () and more hit points, though they cost slightly more.
Ships can also be upgraded by any Shipyard or Repair Dock. Basic Level 1 ships can be improved to Level 2 and Level 3, increasing the ship's hit points and number of weapon slots at the cost of some cargo capacity.
Trivia: 'Snaikka' does not exist as a word in English. Seemingly an attempt to translate the German Schnicka, it doesn't look anything like an English word, or like any other language, except perhaps Finnish.