To add a little more to my post, the law of physics we are talking about is Archimedes' principle:
en.wikipedia.org/wiki/Archimedes%27_principleThis is a great interactive blog post that takes you through it starting from the basics:
ciechanow.ski/naval-architecture/I actually found this blog from his post on airfoils which is directly applicable to how our foils work as well:
ciechanow.ski/airfoil/They are long reads but I find them really informative.