My niece hit bottom in the river, and she made it another mile almost to the dock when the boat quit pulling. (She jumped in and towed it in). It is an OMC sterndrive, looks like a big Chevy 4 cylinder to me. The transmission feels like it's going into gear, but the prop don't turn. I pulled the cotter pin, put a 1 1/8 wrench on the brass nut, and with one finger, spun the prop backwards to unscrew the nut. I pulled the prop expecting to find a shear pin of some sorts, but there isn't any. The prop has two of the 3 blades slightly bent at the ends, and the lower unit skeg is slightly bent. Is a shear pin built into the prop, or is there something inside the lower unit that I need to look at? Thanks.