Water is compressed over the hole. As it passes over, it draws air into the Chunnel (channel/tunnel). It is the principal of the U class racing boats on pontoons. Each side panel is veed out with hard concaves toward the rails. Check out the pic of the hole.
★Rob Machado Experiment- Finless Alaia
Standard finless alaia ,only foam and glass. Two side biter concaves to the convex rail at tail. Have to lay up the carbon flap so when rob steps on the tail the finlets pictured above pop out the bottom. Other wise when trimmimg it rides like an alaia.