It would make sense to ask the current owner if he has had any of the issues you mention. All the items you mentioned apply to some boats, not all, of course. (Not sure what the fueling problems refers to). If you have an inspector (surveyor?) checking out the boat that should answer some questions for you I would think. Why not request a water test with the current owner. Take the boat out for a test ride and check the bilge pump, and all other electronics. Then after putting the boat back on the trailer ask to check the inner hull drains (
Inner Hull Drains...the official word from Triumph) to see if you find any water. Only you can make the decision of course. There are hundreds of happy Triumph owners here if that helps.