Best defence when you are able to, build a raft, you can live on that for the first month, get to a swamp area with a box base raft and pick up some plant X, you can defend your base with plant X boats, I'll see if I can find a picture of one, they won't attack titans as far as I know or maybe gigas but they'll push back anything else pretty easily.
Plus I build too much when I get time to get on Ark heheh.
Hah, it is possible, a little tricky to work with some times as there's no real ' circles ' to work with. But it's one of my fave things to do on Ark, just build random stuff to see what can and can't be done =P