Isaac_Clark has it right. While access to bronze makes it easier, a raft and antler pickaxe are all you technically need to harvest chitin. (You could possibly make the Abyssal Razor before ever building a forge!) This means you can feasibly have an iron-equivalent knife before killing the Elder.

The Abyssal Harpoon allows you to drag targets where you want. This means being able to beach Serpents and wrangle Boars/Wolves.