Hate to disagree- but I once owned a boat that the previuos owner used 5200 on.. Had core rot everyplace that the 5200 had dried up and leaked.
I suggest using the epoxy method described above. But go further, bend a nail into an "L" shape and gouge out a hollow with a power drill in your coring to create a washer of sorts. Then fill the hollow with thickened epoxy. It will also take the load better.