Pearson 424 tang bolt

[Petedd]

I am refurbishing my Pearson 424 spars and have removed all hardware but can't get the thru-bolt that holds the lower shroud tangs on the main mast. This bolt, looking at the thread end, has what I assume is a compression tube over it but it looks more like a stepped bolt. I cannot get the bolt to come out (no amount of pounding or PB-Blaster will do). Bolt turns freely.

Is this typical? A sister ship owner told me that his yard had to cut the bolt out and replace it. This will be tricky as there is no space between the bolt and the tangs.

Advice on how to proceed would be greatly appreciated.

Pete