I Thought Boat Props Were Complicated

Metallurgy at it's best... and then some.

 

I watched that last night too. I believe the pigtail sprue does in fact select not just any one crystal, but one that has a preferred lattice orientation. That is why it wins the race. Twenty ton root loads on a half-pound blade at 12,500 rpm for 10,000 hours is pretty amazing, though. $30 - $40k a pop.