your rudder is supported by a pintle bearing, a piece made of stainless steel where the bottom of the rudder shaft sits.
This part is bolted into the base of the skeg. You will find the bolts if you sand off the GRP that covers these bolts.
You will also need to remove the U-shaped stainless steel part that bears a nylon bushing, at mid-height. This part is also bolted into the skeg. Sand off and you'll find the bolts.
Then, in aft cabin, you need to remove the steering cables quadrant from the rudder shaft top, and open the nylon nut stuffing box.
What is the reason why you want to remove the rudder blade?
Have a good day.