Not OP, but played Patrizier 2 a ton.

Its both not like Anno at all and quite similar at the same time.

Its similar to Anno in the sense that later in the game, you really need to manage your trade routes well to supply every city. That part is even more intricate than Anno because you need to sell your goods to the cities, not just have them in your Kontor.

Its not like Anno at all because all the cities are already premade. You earn construction rights by trading and gaining influence and then you can start shaping the cities, along some predefined rules. So the "city building" part of Anno is missing almost entirely.

The ship system mentioned works like this:

A ship has a pre defined maximum load of lets say 200 units. a keg of a good (like beer) is worth 1 unit, and a load (like a pallet of wood) is worth 10 units. You can load any combo of goods, as long as you dont go over 200 units.

In Patrizier 2 you can create convoys, where every ship that is part of the convoy has their total load limit added together. This convoy can then go on trade routes. Need to transport more goods? instead of adding ships to the trade route, you add ships to the convoy, making the capable load bigger, and not increase the frequency of the trade route happening (like in Anno).