Before messing about with straightening the mast, raise it and see what it does with the standing rigging at work.
My mast had a bend to one side starting right above the spreaders for a bunch of years. The bend made the mast head lean about 3 or 4 inches to one side and I think it happened in early 2000's when the boat still belonged to my dad. The story as I understand it is their rigging tangled with another boat's while being towed back to shore in Long Beach or San Diego - they forgot their rudder and volunteered to be the committee boat for a race and things went awry when being towed.
To straighten the bend, I used an oak block that I contoured to the profile of the mast, placed against the bend and then a 4x4 post on the opposite side of the oak block, along with 4 ratchet straps to slowly counter bend the mast. I went in stages and used two straps per side so I could gradually tighten and then let the straps loose and sight the mast for true.
The amount of counter bend I had to induce to actually make the mast straight while at rest was mildly terrifying! At first I did a little, but a little wouldn't do it, so the little got more and more. I just kept trying to get a little better each time until it was darn near perfect. I would loosen one set of straps per side at a time so the mast didn't spring violently the other way when I undid one.
I have worked with aluminum storefront extrusions (2"x4-1/2" rectangular tubes) for years and know that they can be bent into a fairly tight radius without causing failure so I was kinda confident in what I was doing. Even so, I feared buckling the metal and having to buy a new mast.
I don't have a great "before " picture, but you can see how far from straight I needed to go in the opposite direction to fix a 3 or 4 inch offset. This was done in November 2017 so through the past couple boating seasonsz I've throughly tested the fix and am pretty confident there isn't going to be catastrophic failure... at least not from what I did.
