Dock

The Dock enables visiting Merchants and the use of Transport Ships to travel to different islands.

The Dock can store a total of 630 Resources (food, wood, stone, charcoal, iron ore, tools, and armaments).

Uses
Building one Dock allows selling and buying resources with foreign Merchants.

Merchants sometimes have special "items" that can be purchased to add permanent bonuses or "decorations".

Transport Ships can be unlocked by having at least two Docks. Transport Ships can pick up and drop off Resources between Docks allowing you to move Resources between distant areas of the map or islands. Transport Ships are the only way to cross. Transport Ships can hold up to a total of 270 Resources.

As stated before, the Dock lets you use Transport ships to two different Docks. This allows, say, a colony on the other side of the map to benefit from your industry on a different side of the map. In some cases, the island you desire to colonize has a shallow water connection. This makes it where your citizens will build the Dock, even if they have to travel across the world.

A Dock can also be used as Food storage since it can hold more Food ( max) than the Granary or the Small Granary. Such a Dock can be protected from Vikings by using Piers or Bridges to create a seawall and a Drawbridge to restrict access to just friendly ships.