Checking for rot?
 

I am looking at buying a project boat and wanted to know how I would check to see if the floor needed to be pulled to replace stringers or in my case balsa. I assume for the transom I would have to bang on it as well as drill holes from the inside to see if I find dark wood?

Re: Checking for rot?
 

check is to see if the floor is soft, spongy, etc. you can tap the floor with a platic mallet to see if you hear a thud or tap. the good spots would yield a solid sound whereelse the spots that have delamination, rot would sound more hollow. consider a marine surveyor for a second opinion.