Can anyone point me to a shop (preferably in Australia) that has these in stock please?
Well wadaya' know!! 
At some time in the very distant past I must have thought it was a great idea to get a few of these just in case I needed them.On a vague memory, I went through my odd and ends old stuff box and found I have three of them already! Problem solved! Happy days!! 
The post bag they came in tells me I got them from SOS surf. From memory, that was a Western or South Australian Fin company that am pretty sure has gone long ago.
Stainless split pins work well too. Just flatten off the broken tab, drill a hole and glue in.
Select to expand quotesailquik said..
Well wadaya' know!! At some time in the very distant past I must have thought it was a great idea to get a few of these just in case I needed them.On a vague memory, I went through my odd and ends old stuff box and found I have three of them already! Problem solved! Happy days!!
The post bag they came in tells me I got them from SOS surf. From memory, that was a Western or South Australian Fin company that am pretty sure has gone long ago.
SOS still exists in WA but is now only kiting, SUP and surfing no windsurfing. It is still run by John Geyer.
www.sossurf.com.au/surf/
Select to expand quoteGrantmac said..
How do these work/what do they do?
Replace the broken off tab on a US box fin.
After some router work to mill some thickness off
Select to expand quotewestozwind said..
Stainless split pins work well too. Just flatten off the broken tab, drill a hole and glue in.
That is bloody gold. Never heard of it. Ripper tip
Select to expand quotewestozwind said..
Stainless split pins work well too. Just flatten off the broken tab, drill a hole and glue in.
It's the wrong end man . The screw clamp end , not the pin .
Select to expand quoteMark _australia said..westozwind said..
Stainless split pins work well too. Just flatten off the broken tab, drill a hole and glue in.
That is bloody gold. Never heard of it. Ripper tip
What are you guys smoking , it's the other end .
A split pin has a hole in the end.
Drill a hole in the longitudinal axis of the fin where the tab should be.
Glue the split pin in, so the holey end now creates a hole for the fin screw. Would be good enuf.
Some good acid guys ?
Why would one steel line a hole for a bolt to go through , when there is no front left , because it's broken off , hence , the steel thingy in the original post that is wanted .?
Bunnings has 316 stainless steel split pins..I looked today and reckon the 4mm looks to be the one....great idea should work well.
Select to expand quoteMark _australia said..
A split pin has a hole in the end.
Drill a hole in the longitudinal axis of the fin where the tab should be.
Glue the split pin in, so the holey end now creates a hole for the fin screw. Would be good enuf.
What ?
A split pin has a hole all the way through.
Huh ?
Out about 90 deg ?
Has someone spiked my beer , you guys 
Select to expand quotemr love said..
Bunnings has 316 stainless steel split pins..I looked today and reckon the 4mm looks to be the one....great idea should work well.
WHAT ?
Its not the 4 mm pin that needs replacing .
Its the other end , with the screw , the screw plate , the clamping end .
Switch on Imax. 
the tab is gone.
we want a hole in the vertical axis to run a bolt thru.
a split pin glued into the front of the fin could acheive that.
Select to expand quoteMark _australia said..
Switch on Imax.
the tab is gone.
we want a hole in the vertical axis to run a bolt thru.
a split pin glued into the front of the fin could acheive that.
I'm trying soooo hard .
The tab is gone , **** , no tab .
Hence no room for another hole or anything . Unless you want to drill through the front of the fin . Is that not what the steel thingy above replaces ? The missing tab ?
If there was still some tab left in front of the fin , a simple another hole is needed . And not the steel thingy .
Where and how could a split pin work here ?
Am I having a tumour ?
Yes lol
Because you can't buy those tabs anymore - or bloody hard to find. So anther solution as suggested above may be a split fin
Drill into fin and glue in. Creates an eyelet for bolt. Not pretty, could work.
With limited tools and skills , I would bend some 2 mm stainless sheet into u U shape . 10 mm x 60 mm long. With a file or grinder reduce fin base 2mm deep x 20 mm back . 3 small countersunk screws . Two on one side , one on the other .
Ok , I see where the , ( my confusin ) , is . 
There are split pins and split pins .
I was thinking hollow dowl split pins , and you were thinking cotter split pins .
Bendy split cotter pins could work
I have used a 4 mm hollow split pin to replace the other end pin .
Anyone want the acid I'm on ?
Select to expand quoteImax1 said..
With limited tools and skills , I would bend some 2 mm stainless sheet into u U shape . 10 mm x 60 mm long. With a file or grinder reduce fin base 2mm deep x 20 mm back . 3 small countersunk screws . Two on one side , one on the other .
Ha ha, that's exactly what I was thinking. Make a paper template then grind.
There is also this one, looks new, never seen it before. www.ebay.com.au/itm/254187107847
Select to expand quotekato said..Imax1 said..
With limited tools and skills , I would bend some 2 mm stainless sheet into u U shape . 10 mm x 60 mm long. With a file or grinder reduce fin base 2mm deep x 20 mm back . 3 small countersunk screws . Two on one side , one on the other .
Ha ha, that's exactly what I was thinking. Make a paper template then grind.
By coincidence, I have a used fin I got in a clearance with a repair very like that. It was my plan 'B', but didnt need it. Should have got a photo. Will post one when I get back Monday. I could be wrong, but I think it might be a tad thinner than 2mm sheet and it looks like rivets holding it together. It is supporting a cracked and split tab.
John Skinner used these on all his Torquay Sailboards fins.
0.5 mm stainless would be ok. 2mm is very heavy duty.
they only work by allowing some give by bending when you hit something. Then it's either replace or try to straighten.
Maybe drill an over sized hole and press in a plastic grommet, drill hole for a screw. that could pull through when you hit the thing you shouldn't be sailing near.
Select to expand quoteRAL INN said..
Maybe drill an over sized hole and press in a plastic grommet, drill hole for a screw. that could pull through when you hit the thing you shouldn't be sailing near.
Still got a couple of these fin savers that were meant to do exactly that, but would only really work on an original glass tab as they need compression to work:
