I am going to buy a Intex Seahawk 4 inflatable boat soon and I want to build a plywood floor so i can stand up and fish out of it. I have looked up many tutorials and seen people make this project but I haven’t found out what type of ply wood works the best. I’ve checked home depot’s website and every kind of 1/2 inch plywood is either interior rated or exterior rated but pressure treated. I was thinking about using this: https://www.homedepot.com/p/Columbia-Forest-Products-1-2-in-x-4-ft-x-8-ft-PureBond-Birch-Plywood-833185/100020218 But it says that it’s only meant for interior use. The things I would like to know are:

1: Can I use the originally mentioned plywood if I water proof it? And if I can, what products should I use on it to make it water proof and in what order should I put them on?

2: Is there a better, more waterproof type of 1/2 inch wood that won’t rot and is rigid enough to support weight?

Thank you to anyone that can help. I really do appreciate the support.