trying to remove a spinning coupler bolt

[rapture60]

This may be going to the wrong group but we sailors who do our own maintenance understand....I'm replacing the 2 bolts that hold the packing gland on my shaft...Boat is a Passport 40...
working in the bilge, no swing room.... first bolt no problem second I cut off the frozen nut end and freed it from the last coupler however the bolt 3/8 hex with the head intact won't come out... freely spins both ways. I suspect thread damage inside the female threaded bronze coupler....any suggestions to getting it out?
Heat is a last resort...one where it is with all the boat wiring, and usually heat is used to expand frozen bolts....the last resort would be heat to expand the bolt to grab hold of the coupler and with a spanner or socket remove it...
I'm going to try a crowbar to push the bolt to one side forcing pressure when I try the spanner to turn the bolt....
The final answer is remove the shaft from the transmission and slide the couplers off and work it out in a shop but that truly is something I want avoid...
Thanks for the creative solutions.
Chris

[scraph]

If you could get a power tool on it ... ie an electric drill with the proper socket driver ... you might be able to spin it fast enough to catch whatever thread remains and work it out.

Or ... if on the female side ... you have access to the back of the bolt ... maybe you could put a drill to it. The idea would be to get the bolt spinning in the "outward" direction while applying outward pressure to it ... so the drill bit would have to catch.

Or ... grind/cut/drill off the head of the bolt and seperate the halves at that point.

Or ... that last thing where you remove the shaft and work on it in the open sounds best.

[rapture60]

3:30 AM today I started with a crow bar pressing the bolt, somewhat bending it...I then with a small ratchet had enough pressure on the bolt to recut a few threads and by 4AM it was out...Cleaned the hole with my dremel tool, then re taped 3/8' hole using a baby ratchet as ther is no room with wiring, shaft and shape of the bilage....to use the tap tool or drill etc,,,
All is well new bolts in and working fine.