I sent my Minisimmons to get a pair of Mark Richard-type fins glassed on and, among other things like more abrupt turns and reaction times, etc., I noticed a distinct humming sound in certain waves.
Not that it bothers me at all and I haven’t noticed anything wrong but I was told that perhaps they were not fitted on properly (wrong angle, toe, cant, dunno).
The other day, for example, I caught a rather big left and for a few moments it was like someone was blowing the top of a beer bottle next to my ear.
It’s a blast when it happens but, if it is because of a bad job, I’d like to know.
When I’ve had that hum it’s been the result of the uneven foil or outline in the trailing edge of the fins. I was getting some cavitation as speed. A few minutes of clean up with a sanding block on the flats or sanddpaper wrapped around a soup can for the curved trailing edge has always done the trick.
A bad job then. Is it a common mistake among shapers or is it just plain sloppy work?
I think I’ll leave it as it is anyhow. Don’t want to tamper with such a delicate element given that it doesn’t effect the ride at all (at least at my very modest level of perception).
EDIT: I had come to think that the fact that the fin was now actually a part of the board was what made it resonate with the whole body. Like a musical instrument. Ignorance is bliss, isn’t it?
Look the bases over carefully for any snags or deviation. It sometimes doesn’t take much to cause hum. It also doesn’t take much sometimes to fix it. Just a few minutes with some fine grit wet/dry sandpaper might do the trick. If it’s glossed you might have a can of clear spray can stuff handy to cover any exposed weave when you’re finished.
Not necessarily a “bad job.” The tiniest bead of resin on the trailing edge can cause fin hum. As said by others on this thread, take a good look at the trailing edge of the fins and clean them up. Or don’t, since you’re saying it doesn’t bother you.
Thanks for your help! Not so annoyed if it wasn’t necessarily such a bad job. (rip-offs are not nice).
I’ll leave them as they are just for the fun of it, then.
since it sounds like “blowing on top of a bottle” You might try staying off the lip.
Also, fins have been humming since glass ons have been in existence coming out of pro shops. Unfortunately as a start to finish board builder, you have way less things and people to blame.