To relate one manufactured hull is not an example ...
Take a look at some others ... I have one where the thrust in VERY negative . AND , its manufactured !
but , none the less ....
All , in all , there are general rules of thumb , and then there are the exceptions .
Either way .
And FTR - comparing a surfboard , which utilizes an external force , also , can not be compared or exampled to/against airboats which are self-powered .