Quobba fins

Shaun Hanson's picture
Shaun Hanson started the topic in Tuesday, 21 Aug 2018 at 4:38am

Anybody tried these fins

reecen's picture
reecen's picture
reecen Monday, 18 Sep 2023 at 10:53pm

Thinking about getting a set of Quobba’s. Has anyone on here tried these and got any real life feedback?
Have been having my quad setups vibrate when pushing them hard and apparently the quobbas stop this?

udo's picture
udo's picture
udo Tuesday, 19 Sep 2023 at 10:13am

Vibrate ? What Brand of Fins ?

reecen's picture
reecen's picture
reecen Wednesday, 20 Sep 2023 at 12:47am

Futures fins in quad setups. (2 different sets) only happens to me when pushing really hard through a bottom turn on waves that have some juice.
Slows you down rapidly though.

udo's picture
udo's picture
udo Wednesday, 20 Sep 2023 at 6:31am

From Surfing Waves Site :
Pressure differences = Vortices or Turbulence = Vibration = Humming Fins

The long answer:
As water flows around a fin there are different pressures on each side of the fin. Water flows meet up at the trailing edge of the fin, and in cases with very different pressures, vortices or turbulence can be generated. These vortices push and pull on the trailing edge of the fin, causing it to vibrate. This vibration creates pressure waves or sound. Think of it as your voice when you blow air across your vocal cords.

Have you noticed that your fins hum at certain points while you are surfing, for example during a bottom turn on a fast wave? The vibration hum can be amplified or louder in cases of resonance. In fin terms resonance happens when the pushing and pulling from the vortices causes the fins trailing edge to move back and forth how it wants to move naturally. Or more technically, resonance can be defined as the circumstance when the force applied to the system is equal to the damping or resistance of the system at the systems natural frequency.

How do you fix it?:
Sand the sides of the trailing edge with a 100-150 grit sand paper (give it a few passes) and then surf it, if it still hums then give it a few more passes with the sand paper. The idea is to minimize the pressure difference at the trailing edge by sanding off any imperfections that may have been left from the production process. Make sure you don't sand too much, the more you sand, the sharper and more dangerous the trailing edge gets.

If this does not Fix it you may have a Finbox out of Alignment.

BRAVOsurf's picture
BRAVOsurf's picture
BRAVOsurf Wednesday, 20 Sep 2023 at 8:55am
reecen wrote:

Thinking about getting a set of Quobba’s. Has anyone on here tried these and got any real life feedback?
Have been having my quad setups vibrate when pushing them hard and apparently the quobbas stop this?

Have used the Quobbas - mostly in Indo on long walls (Ulu/Padang and even Keramas).. They 'hold' the wave incredibly well. Never a doubt of sliding/slipping sideways on a deep fast bottom turn, or on a Highline (you can ride a Highline even 'higher'.).. even more so on a Quad. So you can pump and turn as fast as you like and they'll ride like you're on traintracks..
They won't hum - they're extremely well made... But as the other comments, if you're humming, maybe the finboxes are out of alignment....

reecen's picture
reecen's picture
reecen Sunday, 8 Oct 2023 at 9:55pm

udo / BRAVOsurf thanks for the replies above.
Might have to try both, sanding the trailing edges and grabbing a set of Quobba's for some speed lines.
Appreciate the feedback.

soggydog's picture
soggydog's picture
soggydog Monday, 9 Oct 2023 at 11:04am

I’ve used Quobba’s as a thruster set up. They pretty much do what they say. They’re fast and the grip is unbelievable. Definitely worth considering if you’re riding fast down the line waves. I was lucky enough to get a set for free. That’s all I was using until I snapped one. You can also replace individual fins with Quobba too I’m pretty sure.