Hi-
I was wondering if this is a common thing and if anyone else experiences this. I have a 6-0 twin keel fish with Gephart fins and I’ve recently noticed on bigger/faster waves I can hear a whistling sound. Is this common? Is there are way to tune the fin to get rid of it?
Cheers!
AG
You obviously have not surfed a certain Sunset Cliffs wave where the fish was spawned. If you had you would know that THEY ARE SUPPOSED TO WHISTLE. Some yell, others scream. The more noise the more waves!
That should be easy to fix. Get a sanding block and sharpen the trailing edges of your fins. Especially near the rear side of the tip. Water is coming off of your fins in a turbulent manner, which is causing the whistling sound. I had the same problem with my last board. After sanding, the noise went away.
Edit: My board was a single fin. I don’t know if twin keels normally make that sound or not.
A.K.A. “fin hum”… My very first board did that, sort of a whistling hum thing, depending on speed and turn. Asked the shaper that was giving me pointers at the time what the heck I did, and he told me how to fix it, but decided I didn’t care in the end. It was my first board I shaped myself, horribly fat, piggy, and horrible rails that somehow weren’t even quite round. People stared at it when I walked by. But it surfed, I was stoked, and the fin hum was kind of like surfing and playing music at the same time. Sort of wish i still had that board in a way…
waxfoot
p.s. - gently sanding the fins (trailing edge) as posted above was the fix that was suggested…
Whistle is an abnormality near the leading edge.
Hum is usually trailing edge near the base.
Can also be fins that are too flexible.
But smooth out the leading edge with some sandpaper first.
Could also be that the fins don’t know the words.
Blakestah has it, see if you can go fast enough to make a sonic boom.
Hey just noticed your pic and the board you are holding and the fact that you are in San Diego - a retro fish without the butt crack - looks a little rounded on the end - Is that anything to do with Bill Thrailkill?
Cheers
Richard
Yep. Also, the curve of the tail was traced from a trash can lid. Another suggestion from Bill. It rides great.
Hey I made one too!
Bill kindly sent me a template last year and I knocked this one up - I love it and it’s become a real head turner - loves clean waves upto head high - very fast and tons of drive…the iron makes reference to the similarity between the template and my mother’s ironing board…
Where would we be without Bill? He’s been my guru for some time and never fails to deliver the goods!
Cheers
Richard
I let my one pair on my fish whistle whenever they want. Only because that means the waves are actually overhead and I have attained a good amount of speed. I don’t get to hear it that much where I live.
Whoa Richard - double fin box?! Had to clean my glasses to make sure my vision wasn’t fuzzy and I wasn’t seeing things… What’s the scoop? How does it ride? You notice any difference from just having a single with those fins so close?
Thirdshade, that double fin box is something I also picked up on from bill, when he was discribing how keel fins work. not seen one before but its just as I imagined, Bill really knows his stuff. Have you tried it with 2 single foiled fins with the same template yet. I guess you’d have to make though.
The close twin fin set-up was all Bill Thraikill’s creation…i’m just a follower…it’s designed to reduce stall in turns - complex hydrodynamic theory behind it - sort of venturi effect water flow over inside foils of fin resulting with a setup that can handle a higher angle of attack without losing grip or drive…It’s a very fast board I found it threw me off in turns to start with but as soon as I slid the fins forward I was laughing…quite literally - turns on a sixpence - the lack of buttcrack seems to make take off earlier…
I haven’t made it with a single fin so I can’t really compare…but hey you should all try one!
Cheers
Richard
never heard a fin whistle, but I’ve had them hum…
When you finish coat the fin (if home made) there can be a accumulation of resin at the edge. This has to be sanded off so the edge is fair.
HOWEVER don’t sharpen your trailing edge too much (nor your leading edge). I have a nifty scar from a ragged trailing edge… so think about how sharp you make 'em. I also got a hole in the head one day… they bleed like mad… drove to the hospital… quite dramatic.
Nowadays all the noses of my boards are rather blunt. I REALLY don’t like the sharp tips I see far too frequently. They serve almost no purpose and only make it easier for the glasser.
I guess it is more of a hum than a whistle. There were a few good comments made about the positives. When I’m surfing small crappy surf I never hear the hum, but when it gets up to head high + and I’m flying down the line, she starts humming. So at the end of the day I guess it is a good thing that I should be looking forward to hearing more often.
AG
sent you a PM about your board Richard…
Aloha woody - do you recall the thread that discussion about twin fins is in? I’d love to read more but swear that I’m horrible at using the right search terms to find what I’m looking for. Seems to take me ages to find things sometimes…
Hi Aussiegringo,
I just heard my fin whistle once, with a twinfin on the bottom turn in DOH.
There was a high pitch whistle when I pushed the board too much.
This was on a very short wide board, too short for the conditions.
It was controllable with the pressure of my small toe, I think this was cavitation.
That was scary on the edge of spinout.
The hum I never heard on a surfboard, only on a windsurfer with too flexy fins,
With a pure glass fin on a windsurfer I heard the whistle too, at high speeds, just before spinout.
Maybe a layer of carbon on the inside of the fin can take the hum away or turn it into a higher pitch whistle at higher speeds.
I would be interested in the results, good luck,
Soul
I fixed a thruster glass on center fin and got the whistle. There was a sharp bead on the leading fin edge. It only whistled when I went left, and it was LOUD as in everyone else in the water could hear it. A little sandpaper and it was gone.