Take a look at this video on YouTube:
*** note I have removed this video link as I was advised this was for a motor boat and would of damaged my ruddder , so I’d ignore the post completely ***
This is an interesting video where they removed the rudder from beneath the hull , using leverage , my rudder does move from side to side , so maybe a combination of this method and also hammering the rudder from the top May do the job , three man job at least . One on rudder moving - one on plank leveraging downward pressure and one up top , hitting the rudder with a sledge hammer ? Hmmm this makes sense to me as when we did you quite a bit of force with the lump hammer , we didn’t rotate the rudder nor did we use any leverage and the rudder didn’t budge a mm for all our efforts . What you think ?