This is the skeg and skeg support beam up to the counter with the rudder bar behind sitting in it's plain bearing. The rudder blade is still to be added.
The skeg is 1" thick and, to give slightly more prop clearance, is mounted under the hull baseplate. The front end of the skeg is chamfered to reduce the chance of engaging on an obstacle.
Above the rear deck:
At the top end of the rudder bar (supported by another plain bearing above the rear deck) is this square block. It is tapered and keyed as shown to fit the rudder bar thus allowing the considerable torque imposed by steering the boat to be handled
The Z-iron is welded to this block.