How to remove tough through hull fitting

[sagablu]

If you are going to discard the thru hull, the fastest way to remove it is to smash a wooden plug in from the outside. Cut the wooden plug as flush as you can. Then using a hole saw slightly larger than the hole, drill the flange off. The wooden plug keeps the hole saw centered. Takes only a few minutes per thru hull.

If you consider the time you will save, it may be cheaper to start with a new thru hull than trying to save the one you have. keep in mind once its off, you have to clean the old caulk off, not so easy or quick.

[NahanniV]

Originally Posted by Taipe

When attempting removal of a thru-hull fitting, external grinding should be done ONLY as a last resort due to the risk of damaging the hull. If it is ever necessary to sabotage the nut a/o the threaded side either can usually be cut from the interior side of the hull with less risk.

Well, I am assuming some level of proficiency with the grinder.
Working from the inside edge of the hole, with a small grinder,
The debris doesn’t even hit the hull.
Plus, most thruhulls that need replacing are the ones below the waterline, you will probably want to sand the adjacent area to get rid of old sealant and bottom paint buildup, then I usually seal it with a coat of epoxy.

The holesaw idea is cool, but holesaws are expensive, and it seems like it might take a bit of time to pick out the correct size.