Basically a dock would be a structure that sits above the water, and would be permanent, sort of like a raft that you can't move once it's built.
Docks would be made mostly of wood, rope and bone glue, maybe some metal for chains.
It would be built sort of like a wall (that we could walk on), initial corner post and lengths from there, build on shallows or deep water, and the initial corner could be built on shallows only. Building on deep water should be more expensive.
Also boats could be hitched to it, and adding a lock and chain would make it a crime to remove the boat without a key.
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