This keeps coming up. Is this depth story not simple to fact check with simulations? Are we missing something?
According to him the answer is no.
Which makes sense, really. The generated surface waves alone are impossible to simulate, never mind the turbulent wake.
I remember playing a waterpolo match in a pool for diving (really deep and long double the usual), it felt like a slog and it felt like drowning
But he explained that shallow pools can be also be fast for fluid reasons, and not for psychological ones (better coupling of the arms for propulsion by using by viscous coupling to the floor?)