Wharf and Ship
The Wharf & Ship needs to be placed on the main river or a lake. The ship is used to hunt seals and whales for Seal Meat, Whale Meat and Whale Blubber, and to catch Lobster.  

Whale Meat, Seal Meat and Lobster are food while Whale Blubber is used by the Oil Press to make Lamp Oil, or by the Chandlery to make Candles.

Size: 8 by 8

Construction Requirements: 30 Stone, 30 Lumber and 10 Hull Components; Work: 400. Must be built on a shore.

Profession: Sailor

Maximum Workers: 4

could this be added to dock set or get a separate mod? is that possible?

While it's possible, it isn't probable. Right now, Kralyerg is working on MegaMod 9 and still has lots of work to do.  To make this a separate mod, all of the items required to build the wharf need to be included as trade items; otherwise, the buildings that produce Lumber and Hull Components need to be added too or the items would only be available through trade.   The 4 items produced by the Wharf need to be included in the mod too.  Note that the Whale Blubber won't be able to be used for candles.  All of this info is contained in various separate files. At this time, it is unlikely that a single building will be turned into it's own mod.  However, at some point in time, Kralyerg may make additional CC mods that contain groups of buildings with similar functions like he did with the Docks.