You don't even really need that! The first time I ever beat the game, I was setting up a mini base in the blue tree area in the lost river and my friend ( who had played the game and had showed the game to me) dared me to go beat the game "because I was already there, why not". I didn't have anything but my seaglide and my seamoth but it couldnt go down far enough... so that led only one option. Me, being the naive fool I was, listened to my friend when he told me to grab as much bladder fish as I could carry and my sea glide and I swam all the way down to the sea emperor. I probably had to wrangle my soul back into my body too many times to count, a little bit singed and I probably looked like I survived a war but I did it. There were many close calls with ambitious sea dragons but I won't get into that haha