Managed to link some of the islands. Somehow I wasn't able to "harpoon" the other ships. Tried to outmaneuver them, but eventually they got too many and sank me.
What do you mean by you were able to harpoon the other ships. Was it a bug?
I was holding E, put the green square over the ship and released E. The line showed up, but the ship didn't sank. It just kept shooting and moving.
To shoot u actually need to left click, e is just for aiming