My father recently dropped off an old windsurfer that he picked up at someone's yard sale. It's in good shape, as far as I can tell, but is missing the rear fin. I looked it over and can find no info printed on it at all with regards to make or model, except that it is a Bic. It's 12' long, and has two spots for the mast. Does anyone have any idea where I might even start looking to get specs on this thing? I think I can fabricate a fin for it, but I'd love to know what size I need to make it. I checked out Bic's website, but didn't see any vintage stuff.

Any help would be muchly appreciated.