Rudder install question

Had to remove my rudder while boat was on the lift in the boat house and my buddy that was in the water catching it dropped a washer that was between the rudder and the hull. He didn't get a good look at it as it sank to the depths so couldn't really describe to me what I need to buy to replace it. Does anyone know the size of that washer (I.D., O.D., material and thickness) or at least know the diameter of the rudder's shaft? It's an 89 Sport.

Thanks

Thank you. Just the answer I was hoping for but my buddy swore something dropped when the rudder came out and he was sure it was a washer. In looking at it I didn't understand what its purpose would be and of course I couldn't find a diagram.

Thanks again.
Jeff

Ha Jody is right.. someone could have been trying to take the vertical slop out of the rudder. I would recommend doing so on the top side of the shaft if needed rather than underneath where it will change water flow (and fall off upon rudder removal).