"The abtract had a name and address of the owner of the lien but he never was able to get ahold of anybody."
And was that a private party, or a business? I suspect the current owner didn't try very hard. If the lien was paid off, a "satisfaction of lien" would be on file, someplace, somewhere. Otherwise it is all malarkey and no one wants to really touch the tar baby (contact the lien holder) because they might come take the boat.
I'm sure the local (county ?) courts have a provision to nullify a lien and set it aside IF the owner really can't be contacted, i.e. by service with a certified letter, etc.
Can the current owner get the lien cleared? Of course. But if the lien was and is valid, the current owner may still have to pay it off--or surrender the boat. So they've got a very good reason to NOT contact the lien holder.