JP Weed 36...the trailing edge is extremely sharp. I touched it once by accident and cut my finger.
Two people so far accidentally stepped on the edge, and cut their toes.
Does it need to be that sharp? What would happen if I blunt the edge a bit?
I don't know exactly what it would do in practice but according to what I learned last year in physics it will make the trailing edge of the foil slightly less efficient. In practice I would assume that this would make such a minuscule difference that it is negligible. I suppose as long as you ensure there is still a laminar flow over the fin when you sand it down, there shouldn't be a problem.
I blunted mine off at about the bottom inch or two because I got tired of cutting my legs during water starts, or swimming things into position for water starts.
I didn't notice any difference at all but then I don't blast along at mach 2 or anywhere close to it.
Even if it does reduce the performance a little bit I would still do it rather than have my sailing turn into a blood sport.
My shins started looking like a tapestry of knife attack wounds.
Not acceptable! and even though I tried to be careful it still kept happening.
It happens very rarely now.
More than 10 years after a fin cut to my big toe I still can't bend the last joint in it and have no feeling on one side so now I run some wet and dry over the trailing edge to at least reduce the damage that can happen.....
No they don't need to be "knife sharp".
Personally I can't feel any performance change from a sharp to a more "blunt" trailing edge,,
The difference is very minimal on a sharp trailing edge to a little more "blunt" edge. When you give it a few strokes with some fine sandpaper and should be absolutely nothing you can feel on the performance side of things.
As sailors mention above the weed fins is the most common fins where you get in contact with the trailing edge (as the stick out of the back of the board).
If you can run your fingers down the edge and cut yourself - then it is too sharp!
Personally I would give the weed fin a few more strokes with sandpaper compared to a pointer fin, just to be safe.
Thanks guys.
I think it was a disaster waiting to happen.
Just gave it 8-10 strokes using wet and dry on a piece of square wood. It's less sharp now, although still quite thin.
Brushed my toes against the trailing edge of a Talon 38 on Sat whilst rigging.
Nice clean 50x3mm deep cut on my middle toe.
Lots of blood.
Thanks to duct tape and one of the helpful medico sailors was sailing soon after.
But man those things are like razor blades,beware.
I always blunt mine with some fine wet and dry. Have left too much blood in the bay on previous occasions.
Select to expand quoteHarrow said..
I always blunt mine with some fine wet and dry. Have left too much blood in the bay on previous occasions.
I've blunted many a fin on the rocks at Dutchies over the years 
My fins (and most of them are weedies) have a trailing edge about .2mm thick, apparently it's best if the edges are square not rounded, and to stop any hum or squeal from the fin, the rear face shouldn't be at 90deg to fin centreline. Not sure how much of an angle, maybe 80-100 deg.
