The answer, it depends!
It depends on what the planned end use of your boat (user, show or something in between), the condition of your boat prior to restoration and on:
The scope of work you desire driven by the level of quality you desire
Strip and Refinish
New no soak bottom
Need to find original hardware
Length and Beam of your boat
Restorations can cost into the 100s of thousands of dollars for better than original condition show quality - See the article Lovely Rita's Riva, Vintage Boating Life issue #17 - or they can be much less for a well maintained user quality boat.
Typically, but not always our customers desire a good, reliable, user boat - similar in quality to contemporary conventional construction.
General guidelines for good user boats up to 17 feet:
Strip and refinish $1,000 per foot Upholstery $5,000
If wooden seat backs / bottoms flooring need replacement add up to $5,000
Re chrome $3,000 to $5,000
Gauges approx $500 each incl removal and replacement $2,500
No soak bottom $1,500 per foot
Frames, Keel, Stem or Chine(s) extra
Engine rebuild $7,500 and to replace $20,000 Want a new starter, add $250, generator $600, alternator conversion $1,000, carburetor rebuild $600, fuel pump rebuild $200, water pump rebuild/new pump $200
Removal and replacement / detailing extra Other work? structural work? plank replacements? Hardware missing?
So as you can see a complete restoration even for a user boat could cost over $4,000/foot. However, the cost could still be managed down.
Does the boat need a new no soak bottom or is the existing bottom in good condition? Is the engine running? Maybe it just needs a tune up. What is the condition of the upholstery? etc.
Ultimately the costs depend on the scope of work required to get your boat to the condition you desire!
What is it worth when we're done?
It may not be worth as much as you spend on it ..... but the cost of ownership compared to a new boat of conventional construction is better.
In this scenario:
The cost of a Classic boat and restoration$40,000
Value immediately after restoration$30,000
Cost of a new conventional boat$40,000
Value when you drive it from the dealers lot$30,000
Value of classic increases 3%/ year
Value of new conventional boat 45% of original after 10 years
Classic gets maintenance coat of varnish every 3 years Assume all other maintenance is same cost
Difference between cost and value at end of 10 years
Classic $40,000 value, $45,257 cost (original purchase of $40K plus maintenance of $5,357). Cost of ownership was $5,357 after 10 years. New conventional $22,000 value, $40,000 cost (original purchase and OK lets pretend there was $0 maintenance just for fun) -- Cost of ownership was $18,000 after 10 years. What could / would you do with the extra $13,000?