Adds massive cargo ships to the game, that function similarly to trains. Also adds deep sea oil, oil platforms, tanker ships, train bridges and other water based content.
Are you on factorio 1.1.75 or greater? Or perhaps the loaders were the wrong way around (especially if you were on an older version of K2 which didn't have loaders automatically snapping to trains/ships). Loaders work fine with cargo ships for me.
I tested further and loaders do work, but you have to place them closer to the ship. Inserters work when next to the ship and when one tile away, but loaders have to be right next to the ship. I'll have a play with the collision boxes of the ships to see if this can be improved.