Instead of replacing your pylon, you could consider some other options (particularly if the pylon is still attached securely to the bottom of the hull).
You could epoxy the pylon to the corner casting. The bottom picture shows where I epoxied the pylon to the front right corner casting.
You could cut the bad part off the top of the pylon, insert a piece of sleeve inside the pylon and weld another piece of pylon or mast to the rest of the pylon. The bottom picture shows how one of my pylons was welded with a new top section for the pylon.
