Hi Nice Aft

-- You wrote...
From just looking at my own pictures of the MacGregor winch, it seems that bolting it to a heavy plate would not have made a difference. It would have given way at the same point.
That is only true if you place the plate on the WRONG side of the winch mounting face. Place it INSIDE the winch, to replace the skinny washer shown in your picture, and it will not fail at that point again. (Size the plate properly, and you can read that as CANNOT fail at that point again). You will have essentially made the weakest link in the chain the strongest link, and made the next weakest link, wherever that is, the point of future failure.
Metal fatigue should not be at issue here because it's likely the winch was formed from a lower-grade, (not high-carbon, not work-hardenable and not heat-treated) steel, and the radius of the bend is large, especially compared to the radii of the other bends made at the time of manufacture. (And unless the winch has been straightened more than once before). If cracks are present at the time of rebending, they will be visible upon inspection.
Since you're going to get a new, heavier winch, I'm posting this more for the benefit of those who might want a simple, easy way to strengthen their winch BEFORE this possibly happens to them. In fact, simply replacing the existing washer with a larger, heavier washer (and maybe a longer bolt if need be) will increase the force the winch will withstand before deformation occurrs.
Regards.
