INTRODUCTION I used to have some Mares Plana Avanti Quattros (yes, that is what they're marketed as) which were very impressive but flawed in the comfort department. They gave me terrible calf cramp. After asking around and settling on a Jetfin design, I tried on some of these grey fins in a very eminent technical dive shop near Egham, Surrey. The salesman, whom I trust, said that the fins were among the best he'd tried and urged me to have a go with them. They have a design that mimics a whale's fin, he said. It's all about looking how nature's biomechanics work and passing this onto a diver. I must admit I was a bit sceptical.
TRY-OUT I was impressed after a pool session and more or less convinced of their ability to propel the diver efficiently and without undue effort. The vents at the base of the twin blades allow water to be channeled and reduce fatigue on the diver's shins. I often suffer from cramp when wearing "conventional" fins that do not have this feature.
The acceleration is very quick and the kick action can be modified to suit the diver, I now use a flutter kick, which propels me as well as a full leg kick. The twin blades are responsible for this, as they create a hydrofoil effect and maximise the amount of thrust for every fin kick. Buddies have complained that I'm too quick when wearing these, but, as ever, YMMV.
DOWNSIDES The straps that came with the fins were replaced quickly with bungee cord, which allows me to get them on and off very easily and quickly. I broke a strap clip on the second day of diving and decided not to buy new ones because of the price of replacements. Scubapro updated the clips since I bought these fins and, to be quite frank, I doubt there's much evident improvement. I much prefer the improvised bungee fix anyway.
The one thing I miss with these Twin Jets is the ability to "balance" on them, to stop any roll, in other words. There is little resistance on the fin when it moves through the water in comparison with other more solid fin designs. This may also affect your performance when trying to make headway against a stiff current. I have had no real problems. You might get used to this, you might not.
WILL I KEEP THEM? Probably not in the long run. I am now considering changing them for Turtle Jetfins, as I prefer their heavier construction and more rigid blade. They would offer a nicer compromise with the lower fin-kick inertia and perhaps better "balance". I cannot find a pair of Scubapro's Jetfins to fit over my drysuitboot. These more rigid, perhaps conventional, fins are also less likely to disturb sediment in wrecks compared to more flexible designs. Another design I've been told to try out is the Force Fin, but that's for another op!
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