Not enought information to really decide. We have no idea on your skills to
rebuild steel, nor your mechenical skills to
repair the systems on board. However, if your asking the board, I'd say your skills arn't that good, your pockets arn't that deep, and you should walk away from this one.
A "new" 70'
steel hulled
boat costs in the order of ~2 million. That means when you go to
rebuild an
engine, your rebuilding an
engine for a 2 million dollar yacht. The
parts and will cost as if it was such a yacht. When you go to re rig it, your re
rigging a 2 million dollar yacht. If the vessel has taken on sigificant amount of water, basicly the entire interor is ruined. That means your rebuilding a 2 million dollar yacht interoir. And as anyone that's ever done a
project knows, it almost always costs more to rebuild an old
boat, than it costs a factory to make a new one.
And that doesn't even start with replacing plate. More than likly at least some of the
steel hull plates will be rusted up. To replace the steel
hull plates you'll have to have the yacht lifted onto the ground. I'd guess that the boat is going to way somewhere between 60 and 120 tons. Yacht lifts for more than ~85 tons are rather difficult to find. They also are much much more expensive, and not as flexable as travel lifts for smaller yachts. Also, many, if not most, lifts for vessels this size require
insurance.
Insurance for vessels of this size typicaly requires a
captain with a high degree of experence. Well, at least a year or so owning/operating a vessel of at least this size.
And then there is trying to find a place to keep it. Most
marinas for vessels of this size charge quite a pretty penny. After all, it's basicly a mega yacht. Most people that can afford to buy one in the first place can also afford a
captain and crew. They can afford to drop a couple of grand a month in marina
fees. They can afford insurance, and all that that entails.
The costs for vessels that large REALLY seem to snow ball in a hurry. You can sometimes get a vessel for what seems like an exceedingly reasonable
price, but find out that the real value of the vessel is actualy negetive. Some of them arn't even worth attempting to scrap out for the steel in the
hull. In any case, such a project isn't for the faint of heart, limited skills, or shallow pockets.
I have not attempted such a rebuild. Like most people, I love the idea of owning a large boat. I looked into what it would take to try to fix one up. In the end, I decided it was way too much project for myself.
I wish you luck.