Re: 33ft pearson, 1974 soft spot at mast base
I don't think Pearson's have compression posts - I think the masts were generally keel stepped?
Anyway, much depends on where you are, and how much you want to do yourself. I would call a couple of local boatyards and ask them.
It could be a fairly straightforward job; the risk is that when they start on the work, more ugliness appears. However, I have a friend who has recently had this done and it was not too expensive (a couple of thousand as I recall). But bear in mind that the repair is likely to cause cosmetic damage; the top deck will probably have to be painted to conceal the repair.
1) haul the boat.
2) Pull the mast (while you are at it, repair mast/standing rigging, maybe upgrade)
3) Cut the deck a few feet out from the damaged area - remove the "skin"
4) Inspect, remove rotted plywood (likely, Pearson used a lot of ply), make good where neededl.
5) Glue in new ply, fill voids.
6) Glue back "skin".
7) Fix cosmetic damage, restep mast, launch.
One of the biggest issues is the "while it is out" expense. As in "While the boat is out, you may as well repaint the bottom". "While the mast is down, you may as well replace the bulbs with LEDs", etc etc. While many of these points have merit, it often results in the final bill being twice (or more!) as much as you expect.
So call the yards, get a quick estimate of time and cost. Double the cost, triple the time. Honestly. Then if the whole deal makes sense, go for it. Oh, by the way, make sure your great boat purchase price includes the full estimate of repairs, plus a further discount representing the risk (that something else ugly turns up during the work) and inconvenience you are taking on. And be aware that 75% of buyers would walk, so it should be pretty cheap!!
I'm not saying don't do it - I am saying go into it with realistic expectations. Good luck.