I have a set of fcs crv fins that hum This is a first for me in thirtyfive years of surfing. One fix was to make sure there was a constant curve in the trailing edge of the fin. I did that to a few repairs and they never came back. Any theories would be appreciated. The fins hum on two different boards I use.
I got a fish with glassed on keel fins from a locan shaper and it hummmmmms real bad. To the point that I can feel it vibrating under my feet. When I asked him about it he told me that “all fish with keel fins hum.” I want to know if you guys agree with that quote or if this shaper is just full of it. I really have a hard time believing that.
Either way, I am not getting aboard from the guy again, as he insists on doing his own glassing, and the glass on this board is horrible. Great shape but i dont like repairing it every time an insect lands it.
Do all fish with keel fins hum???
i think fins hum because the trailing edge is blunt
He IS ‘‘full of it’’, to the brim! Poor design, and/or poor workmanship, are the usual suspects in fin hum cases. Most cases can be cured by cleaning up, and sharpening, the trailing edge of the fin. There are other contributors to the syndrom, but start there. Only the bad fish with keels, hum. The others don’t.
thanks guys. It makes sense that blunt trailing edges would do that. I would think so because with a thin edge, the streamlines simply come together. When there is a space in between the fluid coming off the trailing edge there is a lot of instability in this gap which causes vortices to form, and when they hit a resonant frequency with the fin vibration i guess it just amplifies it and hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm.
Another interesting point of discussion, it doesnt hum as much when i am pumping or turning on a rail. I guess maybe this is because the hydro force on the fins isnt allowing them to vibrate with the trailing vortices, any ideas on this?
I remember Bill Thrailkill saying that fins humm because they dont know the words.
SF.
Sand the trailing edge…end of story.
H
humming fins are good
cuz it sounds like someone going “whoooo”
so even if yuza kook wit no friends
there always someone calling you into a wave
Do they sound like this?
Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
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mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
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… -hum, because trailing edge too thick or have got a protrude
-hiss, when too much thick and/or poor workmanship in the front edge
no that would be considered bad workmanship
properly tuned fins for lonely people should go like this
"woooohooooooooooooooohhooooohhwwwwoooooooooohhoooooooooo…
I remember reading somewhere on the web Bing saying that in the early 50’s they would screw little screw eyes into the fin and string piano wire between the screw eyes just to make some funny noises.
Yeah!!! Silly the first time I heard the noise thats exactly what I thought the noise was. Only three of us out about a quarter mile offshore. I have had many keel fin fishes not all of them great boards but none of them made any noise. A first for me in thirtyfive years. I do believe it might have something to do with the trailing edge.These fins worked fine no noise used in a quad configuration. Did a number on a tourist epoxy board I couldn’t avoid him just a epoxy stripe on one fin. Surfed the rest of the session no problem. The only change to the fins the epoxy on leading edge is erroded from nephew riding as far in as possible. No carbonfiber showing through.
Any fin makers have any reason why boards make noise is it even the fins?
Could be his fins are properly tuned, then. haha
Sounds like his nephew did the fine tuning.
I always considered humming fins to be a real drag, man.
(Like the way I kept the metaphores going?)
The absolute latest fins go wahoo woot woot woot wahoo woot woot woot wahoo woot woot woot (Simulating cheers from a crowd to fool everyone else in the lineup.)
And on a gnarly section go gnarrrrgash gnarrrgash so you don’t have to prop yourself.
hmmm talking fins (again the metaphore) the next big thing…?
“Good morning Mr Phelps…”
i had two killer whales roll over and show me there teeth last week
i was alone at dawn
they were no more then 20 meters away
i think myfins speak whale
What do they say?
Freewilly freewilly freewilly?
lol
no they say
“not food not food not seal not food”
i hope thats what they say anyway
Interesting. My CRV’s never hummed and always struck me as super low-drag. Then again, they are older- bought them when they first came out- so maybe something has changed in manufacturing technique or QC since they were made.
The crv fins in question are pretty old most other than the noise they still work well. Unwanted vibrations cause premature wear and failure of components. If I could only put these on my static blade balancer then hook up some accelerometers
for dynamic readings. Then the voices in my head would stop DUH