1967 Hansen Fin restore help

Hi guys, a board collector friend of mine picked up this great looking restored Hansen and asked me to help him attach the fin. Looks like it was originally a wave set, with just a single bolt going through the boards deck into the base of the fin. The guys restoring it made a replica fin out of airplane glass, it just needs to be bolted on to finish the job.

Question is where can i get the proper bolt for this? I have a tap and die set to make the proper threads inside the base of the fin. If they don’t sell the bolts anywhere does anyone out there know what the bolt looks like (length, thread, width, ect…) and i can go rummage through home depot.

Second question: the board is missing a box for the fin. Originally there was a plastic box in there right? Looks like the inside however is laid up pretty sturdy with resin/glass and the base of the fin fits in there snug. Hopefully it wont crack up in the water with airplane glass pushing up against it. Cant imagine they sell the box for this thing anywhere, correct me if im mistaken.


Well, you are mistaken about a number of things. The ‘‘box’’ is molded into the board during the glassing process, using a male plug. The fin had a machined base, that matched the interior of the molded box. The original fin bolt was 3/8th inch stainless steel, counter sunk slotted screw. I don’t recall the thread pitch, or bolt length. Perhaps someone with an original one can measure it for you. You are not likely to find a bolt at Home Depot. Contact a screw and fastener supplier. The fin attachment method was conceived by Fred Smole, and the final production setup was designed by engineer Mr. Don Okey. Please note, I’m the guy that shaped that particular surfboard.

Thanks Bill, yeah I see your autograph there on the deck. Cool shape, I like the knifed out rails. If anyone out there can shoot me the length of the original screw and the thread pitch I see a variety of them for sale on amazon… or better yet if you have a spare original one kicking around im a buyer. Forgive my millennial ignorance I can’t find much on the topic out there anywhere.

I’ve got one, but not for sale. I can check the bolt size and length. I would think that you could drill out and insert a nut into the fin that you have with Epoxy. Then find the right screw and put it thru the deck. You can do the hole in the deck in a similar manner that a “drill thru” leash attachment is done by packing the hole with milled fiber. It’s a nice fin, so I’d use it. May not be the original style that came with the board though. And absolutely; Everything Bill has told you is correct and from one who would know. Lowel

As Bill already mentioned, it needs a 3/8" countersunk slotted bolt. That’s what was used for those fins. If the threads inside the fin are not stripped, just take the fin to a hardware store and try a few different thread pitches in 3/8ths size. The length should be easy to figure out. You can see the threads inside the fin, so measure how deep that goes. Then add the difference between the inside of the box to the deck side where the fin goes. That can easily be measured by sticking a pencil through the hole and marking it. Try to find a bolt that is slightly shorter than the overall depth of the measurements you find. You don’t want the bolt to bottom out before it’s snug.
And, as already mentioned, that is not a Waveset fin at all. It is the proprietary fin system specific to Hansens of the period.

I ended up buying a 2" machine thread screw with 3/8" thickness at home depot. Cut 1/2" off it so the screw was flush with the bottom of the board. Then I used my tap and dye set to thread the fin. Rode it Sunday, this thing is fast! What a fun ride!

Looks like you have it covered but here’s this:

Wow thanks Gene, huge Cooperfish fan! Wish I could get a better look at that board too bad that chick is in the way