Hit a submerged rock. Moving at low idle speed in 20 ft of water when depth finder alarm went off and bam hit something hard. Pulled back on the throtle to take it out of gear. When I settled down I put the boat back in forward gear it did nothing but spin. First thought I threw the prop. Kept engine running (it never cut out) and lifted the drive to check it out. Prop still there but can't get it to go in gear. Messed up something inside big time, right? I am hoping I can get some ideas as to what might have happened from the least worse case scenerio to the worse case scenerio before taking it to a shop where they'll tell me I need a new outdrive. Any ideas? Much appreciated.