If you've purchased Subnautica Special Edition and have been waiting for your Hull Plate to appear in your Steam inventory, have another look now. It should be sitting there, all proud with it's unique number and purchase date. Hull Plates are redeemed in waves, which is why you might have had to wait a little while. If you haven't received one, but have purchased Special Edition, double check that you have completed the Steam ID form linked on your Humble Bundle redemption page: The same page where you redeemed your Steam key and downloaded Subnautica's prototypes.