When Jonny Skolnick was in Wrightsville Beach, N.C., for the Carolina Cup paddleboard race in April, he had heard that some high-caliber paddlers were heading north for the fifth annual DeSatnick Foundation Cape to Cape race. But after missing last year’s 17-mile haul from Cape Henlopen, Del., to Cape May because of an injury, Skolnick had something to prove. He won the prone paddle division two years ago, after all.

“This was the most competitive field they’ve had at the Cape to Cape,” Skolnick said the morning after he won the stock…