Now there are exceptions, but the old adage if it is too good to be true, it likely is. I doubt it will sell that fast. The thing is most people will not spend 30 to 40 thousand on a project boat, they will risk a few thousand, but not 40,000 for a project boat. Granted the payoff in the end could be high. They look to be asking around $100,000 on yachtworld (asking not selling) so figure you can get 70-75 for it after your done if up to good standards. I could see a 43 foot abandoned boat needing well over 40,000 in work, especially if it has taken on water over the engine. That is a lot of teak that would need to be replaced not to mention the engine. Upholstery could be several thousand in materials alone. I have heard of folks spending 4,000 or more on cushions for a 30 foot boat. The motor for that boat will be at least $10,000 just for the motor, not including install.
So be careful, it could be a bottomless pit and if your not going to do your own work, run! If you do your own work you might get lucky and break even. Of course boats are not a good investment anyway.
Look at this one for $100,000 looks good and he says he will take offers
Mason 43 For Sale - Simplicity
I have not seen it, but makes you pause before getting involved in a project.