I keep my boat on a trailer in front of my house, and would never even consiter leaving the props on. They disappear pretty often if left on, and the 2 minutes it takes will be wisely spent removing them by you, rather then some guy that see's them. Sounds like you need to buy a 2 5/16 socket. It's not much trouble to take them off. I put my props on at the launch, and take them off at the launch always. I've left them on a few times, and I pull mu truck up within an inch of the prop nut, and go in and then I cant sleep all night, cuz all I can think about is what if my props are gone... I've gotten out of bed a few times and put my truck in the garage and removed the props just to get some sleep. A little hassle for alot of insurance.