Airlocks?

I've seen a few airlocks around in screenshots, how is the liquid pumped out? Or do drains just delete the liquid they drain?

 

Most of the airlock designs use sensors and drains. And yes, drains simply delete liquids

 

Good to know, I couldn't find a pump anywhere on the wiki and I'm not far enough in my current playthrough to have tested it. Thanks.

 

They delete liquids? I wonder if you could drain an ocean world over a long enough period of time that way?

 

Correct me if I'm wrong, but I think Oceans are special in that the water constantly respawns to prevent exactly things like this or draining it all into underground caves.

 

Yeah, Ocean planet liquid is infinite. An airlock would still theoretically function though, as long as it's at the bottom of the ocean leading underground, which is exactly the entrance of my planned base this playthrough.

 

Literally any square in the Ocean that lacks any block altogether spawns unlimited water, so removing walls can be a problem if you're making an underwater city.