The propeller is protected by a removable safety guard that won't let your fingers get through. In case something like seaweed gets caught in it won't do any damage. Most times, you'll be able to get everything out with your hand without removing the prop nut. But if something hard gets caught in there and blocks the propeller from spinning - the motor will detect it and stop automatically to prevent any inner damage. P.S. In case something truly damages the propeller, you'll be able to resolve this issue through our service center.