From our experience you can waste a lot of money umming and ahhing about whether to but a boat or not. But in the back of your mind, no matter what, if you love it you’ll buy it anyway.
Research the boat, find out what other people have done to it in the past, ask people if they know the boat and have any info about it. Other people tend to know more about the past of historic boats than the owners sometimes do!
We wasted loads of money hiring a crane for the day, having Banstead taken out of the water at a yard with no lifting equipment. The survey came back highlighting problems, we bought it any way! We could have put all of that money into repairs. I think that most Historic boats could easily have thousands thrown at them if you had it, but if you haven’t then you can patch them up until you or someone else can afford it in the future.
If you are brave enough, the buy the boat without a survey (knowing a little about the boats past would be wise) use the fact that you are buying the boat without a survey to barter down the price, but know that you might have to spend 5 to 10 Grand just to get it insured
Just my advice! Others may disagree.
Take a chance and good luck