humming keel fins

Hi guys.

My 9" plywood keel fins are humming a bit on faster waves, is this normal on bigger keels or have i stuffed up? so that i can learn for next time would the humming be due to the fact that they are only made from 6mm ply with 2 layers of 6oz and minimal foil?? or have i stuffed up on alignment/cant/toe?

I dont think that the humming s effecting the board too much and its a nice way of knowing that ya have got the trim right…

pictures of the keels…


When that happened to me it got fixed by sanding a little the trailing edge of the fin… give it a try.

Hope this helps.


so , you’re from perth eh ? the west australian one ?

there used to be a guy here who rode a hollow wooden fish , also from perth …"gray murdoch was his name … do you know him ??

I’ll keep an eye out for your board in the water …



yep chipster west oz… nuh dont know gary. I mainly surf at toms and methems and sometimes on the beaches when the banks get right (hopefully soon after this blow)… been a great month of surf hasnt it. Would be keen to catch up and check out some of your boards, you wont miss me big guy 6’6" hws fish. Trying to decide what board to make next… 12 foot hollow section connector or an even shorter fish or MOTE bali board single/widow set up… ah so many boards so little shed space…



good stuff , welcome !

“MOTE bali board single/widow set up…”

Now , THAT one gets my vote …you KNOW it !

let me know when / if you make it , I’d love to check it out !



Had Contacios empty this morning , just me and a mate in head high peaky nor-nor’east for a while …I was riding my prawn …blue and yellow wettie …also EASY to spot !

maybe you , pascal [‘popeye’] and I can get a wave some day soon …[sunday and wednesday are looking the goods , at present , wind and wave wise !]

I have the same humming problem with my 8" maple keels. I don’t think the material has anything to do with it. These are made of solid maple (birdseye maple on the left and curly maple on the right) with no fiberglass used and they hum as well. I would guess that it’s a normal thing with wooden keels (I think it gives it some character). I also have the same size fiberglass keels that I swap these ones for (both sets are FCS compatible) and never had the humming occur.

Kiricore, sand your trailing edges down to a nice, thin crisp edge from tip to base- they should stop humming.

9fish, from the looks of things, you may want to completely re-examine the foils on your fins. Look up George Greenough in the archives, for starters.


The type of wood has nothing to do with your humming problem. Next time take a look at some Gepheart fins. And if you cant find any too look at, save up and buy some off of

Thanks for the replies.

I sanded my trailing edges to i nice blunt 3-4mm to stop getting cuts on the feet, might have to just go with the bloodt toes and sand them down again.



IMHO. You could just except the hum. Be greatful that you have waves that are fast enough to make them hum.

Howzit 9fish, You definitly need to do some more foiling on the trailing edge, not enough taper to the foil.Aloha,Kokua

a timely post ! (Because , I have just finished refoiling MY ol’ blue tinted fibreglass triple-tabbed fcs keels I made . )

I took them out for a surf today , and , even though the surf was pus , basically , I got enough waves to hear no hum , feel much less drag , and …lighter weight , too !

Shane , the trailing edge on mine is 1mm now …before , it was 3mm, and much thicker throughout the WHOLE keel [almost as thick as 9fish’s] , and they definately hummed , were heavier , and felt sluggish .

…It feels like they almost FLEX now , by comparison ! [and , they probably DO !]



I’d be stoked to grab a wave with you some time this week, and to check your hws keel fish in person…

I had a longboard with the same (?) issue. The fin I’d put on there was so thin that it would actually vibrate in a certain speed range. Slow through normal speed was quiet, then it would start humming at “medium fast”, and get louder until I was going pretty darn fast, when it would stop humming.

My nephew broke the fin off one day, and I replaced it with one that was much more normal in terms of thickness and stiffness, and it never made a peep at any speed.