I think, more often than not, he makes the calculations fit the conclusion, not the other way around.
Other than pure science I'm pretty sure that is the way everything is done most of the time.
Politics, religion, relationships, cars, stocks, most other purchases and of course boats.
We select the facts that fit our conclusions. Not necessarily the optimal method but most common.
I got a big kick out of his discussion of hydraulics. He said he installed significant hydraulic systems and removed them because of many issues he mentioned. So all this technology is a learning curve for everyone.