Luck IMHO
All it was going to take was 2 waves back to back close enough together and they were swamped...
That water was WAY too rough to be taking out one of those craft loaded down with joy riders out. Now weather can turn on a dime, so they may just have been too far out when it turned to get back.
That’s what I think happened, is the stormfront moved in with straight line winds, and it it probably slowed down the Duck’s progress being able to make it back to shore. You could see both boats were completely unable to make progress against the wind. Somehow the one made it back.