Sharp fins

kbomb's picture
kbomb started the topic in Sunday, 28 Jun 2020 at 10:36pm

Last wave of the day this afternoon, I jumped off my board into the white water and somehow my fin sliced my palm, like a knife, luckly not too deep but still, i was pretty shocked at how knife like the cut is, will keep me out of the water for a few days. Do people sand fins back a bit? Do they have to be so sharp?

quadzilla's picture
quadzilla's picture
quadzilla commented Thursday, 9 Jul 2020 at 7:14pm

Run a file along trailing edge for any too sharp.

Pops's picture
Pops's picture
Pops commented Friday, 10 Jul 2020 at 9:40am

ten years ago or so I copped a fin chop to the top of my foot (fins were a custom molded set done by a mate of a mate). Water was cold enough that my feet were numb, so I didn't notice it until I was walking up the beach when another bloke asked if I was alright. I looked down and there was blood everywhere... when I cleaned the sand out of the cut, it was deep enough that I could put my index finger in past the first knuckle.

Since then, I've always rubbed the edge of any new fins with a little wet & dry. Probably increases drag a touch - though not enough to be perceptible to someone of my middling talents - and better that than a bad chop IMO.

Funnily enough, I've never had another fin cut, or even close call since...

He who hesitates is lost

blowfly's picture
blowfly's picture
blowfly commented Friday, 10 Jul 2020 at 10:06am

I was out of the water for a month recently after knocking my rear fin out with the outside of my calf. The tip of the fin dug a hole the size of my little finger nail and the impact bruised the whole area. I was chatting to one of the locals last night and he told me that he did something similar but much worse a few months ago. The fin caught him across the back of the knee, narrowly missing the artery, which would have caused him to bleed out, but playing hell with the nerve so he has had neuropathic pain ever since.

Ape Anonymous's picture
Ape Anonymous's picture
Ape Anonymous commented Friday, 10 Jul 2020 at 11:57am

6 stitches to the medial inferior heel, too close to Achilles tendon - dull your fins or expect to be sliced open like a cesarean!
Take 120 grit on a hard/cork block and rub the trailing edge to create a small flat.
Yes, will lose performance / create drag - my fins were foiled by a physicist who used to create rockets - hard to part with that level of advanced technology, but, it's better than spending a month out of the water resulting in a fucked-up twisted spine from hobbling around in a weird position.

Liney's picture
Liney's picture
Liney commented Friday, 10 Jul 2020 at 4:41pm

I remember reading an article in one of my Old Mans sailing mags from the 70’s written by a Frank Bethwaite who was a Meteoroligist and boat designer who did research on foil shapes,chord ratios,finish(dull v polished)in tanks and wind tunnels. and one of his findings was unless the trailing edge was perfect,it was better to have the edge squared off,eg .5mm or so than sharp in relation to drag.I’d say very few of us would be good enough to notice the difference anyway

Backyard Shaper,Glasser and unfortunately Sander

Ape Anonymous's picture
Ape Anonymous's picture
Ape Anonymous commented Friday, 10 Jul 2020 at 4:55pm

"unless the trailing edge was perfect,it was better to have the edge squared off,eg .5mm" that's absolutely correct!
"few of us would be good enough to notice the difference " - you'd be surprised: 'small changes amount to huge differences, think of the amount of pressure on any point of a board at any one time', Tom Hoye.
My experience is that the most subtle changes are very, very noticeable if we simply pay attention - such is the way with the outcomes of meditation on any single point: on investigation, each thing is made of many components -ultimately empty, but also infinite in number and complexity. What's the difference between 0 and 1? Infinity! "small changes make huge differences"

Spuddups's picture
Spuddups's picture
Spuddups commented Friday, 10 Jul 2020 at 5:17pm

Could just be confirmation bias Ape. I’ve stuck a middle fin in place of a side fin and didn’t notice for an entire surf till someone pointed it out to me after the fact.

kbomb's picture
kbomb's picture
kbomb commented Friday, 17 Jul 2020 at 10:56pm

Thanks for the info. Will give them a sand, and from the stories above and others I've heard recently I might wear a wettie all year round!

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