If the teams of usually 6-7 trainees start back a ways from the ocean, they'll carry their boats above their heads.
Sometimes the BUD/S trainers will even make the trainees get wet and cover themselves in sand to "make them really uncomfortable," Davids said.
"It sounds laughable," Davids said, but "people's performance cuts off quickly when they're uncomfortable" and it's all about testing whether they can perform under tough situations.
"Typically every boat team is successful in paddling out past the surf," Davids said. "Boats that don't make it will have failed the evolution and will receive remedial training and additional physical training."
But Davids added that it's not uncommon to witness what he called a "yard sale," in which boats flip, and bodies, oars and helmets go everywhere. Sometimes boats even crash into each other.
"There was a hard and fast rule that during a wipe out each student was to hold onto his paddle," former Navy SEAL Mark Divine wrote.
"Invariably, someone would lose his during a wipe out," Divine wrote. "Some students had teeth knocked out, others had large gashes inflicted on their faces or elsewhere from free paddles."