45’ viking with weak stringers.

YES, you should be concerned. The stringers are the backbone of the entire yacht. The fix is major and you would have to remove and replace and re-glass in new stringers. The cost is extensive.

It's possible. But really a bandaid and not a cure. First you need to find out where the water is getting into the stringers, then fix that, then epoxy, but that's really IMO a band aid and not nearly as strong as a boat with proper stringers.

1990 Viking with marine ply sandwiched over foam board , epoxied and glassed over. Depending on how much delam and moisture is present , I would proceed with caution. They're are companies that specialize in vacuum penetrating and drying out areas like stringers and then vacuum bagging and infusing the areas with resins. Look at past Ship Shape TV for the company that does this procedure.

Found it! Company is called Dryboat.

Yes it s a big concern. Could cause alignment and gear issues. Some builders used the plywood as a structural part of the stringer. Not just as a core. So if you don’t have enough strength in the fiberglass just injecting epoxy isn’t going to be enough.

I would move on. Find another boat with a good keel/stringers ,Viking or whatever you interested in but not this one. There are plenty of other boats out there to fall in love with at a fair price.

Where the hell are you going to find that ?! Good luck. It's hard enough to find a good mechanic or repair person that can do the most basic of things nowadays. I would be nice to find such a LOCAL person.
Add to that every boat builder has its way of doing their stringers, along with changing their way of doing it through out the years....through trial and error and mostly ( save) cost and time .

Try a beige carpet with a sound barrier pad beneath?? Teak and holly is nice to look at, but in a high traffic areas you are going to wind up covering it with a floor canvas or more, IMO

Since you asked for advice on the stringers and didn't follow any of it, what is your solution for the stringers? Educate us.

You can’t just pour Epoxy to replace rotten wood. It needs to be reinforced with a new core. Not only Epoxy isn’t structural but if significant amount of voids are filled the Epoxy will overheat while curing

We recently replaced the salon carpet with some synthetic flooring that looks like wood on the 84 footer I run. Looks great. Extremely tough as we did two trips to the Abacos with thousands of pounds of boxes stacked inbthe salon. No scratches. Completelybeater resistant. I ll try to look up the brand. Only downside is that it is made in china.