What state do you want to get the boat titled in?
There are different procedures in place depending on how you got the boat. (http://www.dnr.sc.gov/boating/registration.html) According to the website if you purchase a boat the seller must give you the title and if they have lost it they must get a duplicate before they can sell it. I am assuming the same is true if you were given the boat. Although because of the year it might have been a previously exempted boat that you will now have to title. (http://www.dnr.sc.gov/boating/index.html) The problem with that is it requires a tracing of the HIN. The website also mentions that it could have a serial number so since you have the serial number they may accept that instead of the HIN. (http://www.dnr.sc.gov/boating/terms.html#hull) Since this is an unique case they do mention how you can contact them for more information at the Boater Registration Office at(NNN) NNN-NNNN That is probably the best way for you to take this matter.
Please let me know if you need any more information.