January 2004

Vol. 19, No. 1     What's this?

Faulty Fin Claims

from the January, 2004 issue of Undercurrent  

Mares Quattro

Claim: Flexing center channels translate leg movement into directional thrust, while the stiffening side rails increase the blade's effectiveness for frog kicks and sculls. (Review in Sport Diver)

Finding: Channeling of water down the fin by troughs or rubber channels (Quattro) does not appear to improve thrust or economy.

Scubapro Twin Jets

Claim: Proprietary drag-reducing vents and extended side plates for increased leverage and power. (ad in Sport Diver)

Finding: The use of Venturis, or vents, either forward or rearward facing, does not appear to improve thrust or economy. Water does not pass through the vents, thus they do not relieve the negative thrust in the recovery phase.

Apollo

Claim: Split fin design allows for more power and less effort than any other fin. (Apollo's website: www.apollosportsusa.com/Biofin.html)

Finding: There was no difference in energy cost between the split fin Apollo and the same model with the split taped closed, suggesting that the split was ineffective in improving economy. The longitudinal splits also do not appear to improve its thrust.