I have a special tool to remove my Volvo Penta Duo Props. However, since I have a special tool, I assume anyone can get a special tool to remove any sort of safety or locking mechanism. I remove my props every fall, clean and store them with my other boat "stuff". I'm a firm believer in "where there's a will, there's a way", so I don't think any lock will stop anyone that really wants your expensive props. It will force the casual thief to move on to your neighbors boat though.