Here is a 6 blade Herring I converted to a 5, I seem [ATTACH=CONFIG]523823[/ATTACH]to be an expert on this, it's happened more than once on various boats.

I slung a blade off a 4 blade Bravo 1 prop last summer. Definitely was due to a crack since my HOs don't have near the torque or stresses a bigger motor has. Still scared the sh## out of me! Luckily it didn't hit anything else. Guess it went down instead of up!