Partly seized engine?

I drove thru a small stream that was 14 inchs deep and 3/4 the way thru my engine stoped. i tried to restart my engine but it did not. i pulled it out and tried to start it but acted like the starter was sezied. i purchased a new starter and it did not fix the proplem i am able to turn the fly wheel 3/4 the way then it wont turn any more. i put the starter back on and it started 3/4 the way but completely stoped. i removed the starter again and the fly wheel will move if i push with a screw driver but only 3/4 the way i though maybe i got water in the engine so i removed the spark plugs but did not help. any one know what can be wrong ( my greandfather said my water pump is leaking