Hey, I've been attempting the same thing. 1st I do not think the oceanic is implemented in stock KSP nor do I think atmospheric is implemented. It doesnt seem to be an issue with having to deploy, as if you tell the module to be a surface you should be able to start and stop harvesting of water. Water must be an available resource under the vessel for the option to pop up in surface mode, so you have to create the water resource and have it populate the planet (i tested by just having the entire planet have 100% water) I cant determine how to tell if the ship is in water however... only when the ship is in the water biome (unfortunately much of costal water is the shore biome). I edited the surface ore scanner to scan for water to help me trouble shoot this. I thought perhaps oceanic may only work when the ship was in the water biome but to no avail, and surface stops working as soon as you are in too deep of water (basically when you leave the shore biome). Harvesting on land has not worked yet, may try to just edit the rill to harvest water and see what happens.
