Originally posted by OctoberSky:

My experience is that there needs to be some fire source. If I have a teleport base with just the port plus the workbench I've never experienced a raid and likewise a farm base with just the workbench. But if I have a forge base then there is a fire source and I usually get the raid.

I had no fire source at my boat dock just a work bench and a boardwalk into the water.