Gday, attached are photos of a fin i have in my old Tyronsea. It looks like an A box but then the little fin-shaped clip at the front has got me confused. i can't seem to remove it and i don't want to snap it just in case it is a required piece of hardware. Despite an exhaustive search on youtube and seabreeze i cannot find any info to tell me what this clip is called, and how to change it out.

i'm pretty sure that if i can get it out, i can bring the A-Box fin forward and screw it in using that front screw. at the moment the screw is not holding anything down, its just filling the hole.

I used the Tyronsea to learn to sail, and still use it for friends etc... but my latest escapades have involved Stand Up Paddling SUP with the Tyronsea and it is ideal. New adjustable Starboard SUP paddle was $150. Much cheaper than forking out over $1000 for a second hand SUP board.

Any advice on the fin is greatly appreciated.

I used to use a similar arrangement to allow my fins to pivot when the hit rocks. I had rubber at the back of the fin, so impact would release it from the front tab, the tab being screw in place.
But looking at yours I think it's slightly different. The fin is jammed hard up against the back of the box, and the tab has no screw. I have a feeling you need to slide the tab forward away from the fin. You may have to rock it forward and backward to release it.

This old memory is playing up, but I swear I've seen one somewhere, maybe even in the bottom of one of my odds and sods boxes, I'll go for a look in a while and report back.

OK you're in luck, in the distant past somebody must have given me one of these things, so I've taken a pic for you.



I think the front bit is missing a small stainless rod in the front hole, but maybe not?
You can see the small front fin, (a canard I think, helped stop spin out), has teeth that engage teeth in the main fin's tab. And side extrusions that run in the finbox's side slots.
So I guess if you apply forward pressure at the rear tip of the little fin, and push down on the front of the main fin, that should disengage the teeth allowing the little fin to slide forwards. Then they can both be removed through the slot as normal.

Hope this helps.

^^^ I knew it looked familiar and was going to suggest a knock with a rubber mallet on leading edge of the fin.
Wasn't game, until Decrep came up with the goods top stuff

BTW I reckon they worked well and could still be useful nowadays

Brilliant decrepit - i'll try this tonight. It looks identical to the teeth at the bottom of my "canard" and hopefully i'll be able to get it out. Although as you say... if it works then leave it there. My issue is going to be that i'll need a fin to fit into the fin box properly and screw in, otherwise i'm better off with the current canard clip.

^^ you ca still fit any US box fin with the normal screw and nut