John 

WHY WALK WHEN YOU CAN RIDE That's what my pioneering-motorist grandfather used to say. When will diving equipment manufacturers realise that what we really want are fins that propel us effortlessly forward without hesitation and into any current, and that never get worn out We want fins that are motorised.
In the meantime, we have to choose the fins that can make the most of our own pathetic efforts to outswim fish.
Gianni Batista, the chief designer from Technisub in Italy, thinks he has the answer. He has designed some fins that have little inherent flexibility in the blade. Instead, the blade simply hinges from the foot-pocket.
What give it elasticity are a couple of silicone straps that work like suspension units. When the fin is bent back by your forward kick, the blade is sprung back. The resulting slingshot effect gives these fins their name.

Blade
I took a pair of Slingshots to try in the Cape Verde islands. Its a place that is getting a name for itself among windsurfers. The blades of the fins were so huge and unrelentingly flat that I did get a few enquiries about where I might fit the mast and sail!

Footpocket
Luckily, the foot-pockets were equally capacious, and could take my large boots right up to, and including, the heel. This meant that my ankles took none of the strain of kicking, and the fins really did become a part of my legs.
This was lucky because, though the Slingshot suspension units are readily adjustable during a dive, even in the softest position they took some effort initially to get moving.

Straps & Buckles
These fins come supplied with conventional straps and quick-release buckles. I substituted a pair of proprietary stainless-steel spring-straps. Watching the remorse of another diver who broke a conventional rubber fin-strap as she put her fins on after a long and uncomfortable ride in mountainous seas proved to me that I had made the right decision.
Luckily, the boatman had a spare pair of fins in her size, but with my big feet I would have had to sit out the dive in the wildly bucking boat. Stainless-steel finstraps can be fitted to any fins and make an immediate improvement, not only to longevity but also to the ease with which you can pull the fins on and off.

Efficacy
I started with the silicone suspension units of the Slingshots set at their point of least resistance - and was a little disappointed by their performance.
We had to swim our kit to the boat from the shore each day, and I didnt feel I was sprinting ahead of my fellow-divers, as I had hoped.
I then adjusted the fins to their fiercest position, and everything became different.
In January, Cape Verde enjoys some powerful winds. This is good news for kitesurfers and windsurfers but less good for divers.
Although there is not a lot of rise and fall of tide, the wind can drive surface currents that make swimming near the surface from the back of the boat to the mooring-line and the downline quite punishing. Because these currents are wind-generated, they are hard to anticipate too.
At one dive site, I jumped in first and found myself swimming flat out to keep up with the moored dive-boat. The water at the surface was passing by at a lot more than a couple of knots, which I would say is the limit for any sustained swimming effort. Thank goodness I was wearing these powerful fins, and had the heart and leg muscles to make the most of them.
Under water, they powered me along. However, there is no free ride. My Galileo computer recorded heart rates of between 49bpm (when I was making a shallow deco-stop) and 180bpm (when finning hard into the flow). I never realised I had such a range of heartbeats at my disposal!
So the Slingshots deliver performance - if you have the fitness and ability to use them.
The other thing I noticed was that, with such large blades, I was really affected by currents that my fins were in but that the rest of me was not. For example, lying under low overhangs to try to get some elusive shot with my big camera, my protruding fins would act like rudders and drag me slowly round.
They were also slightly irritating each time
I touched something unintentionally, such as a part of a wreck. I would have second thoughts about using such big fins in conjunction with a camera near a fragile coral reef.

OTHER COMPARABLE FINS TO CONSIDER:
Mares Raptor90
Scubapro TwinJet Max £150
Force Excellerator Tan Delta £350


Divernet Divernet
SPECS
TECHNISUB SLINGSHOT

PRICE £100
SIZES S, R, XL
COLOURS Blue, red
WEIGHT 2.7kg size XL
CONTACT www.aqualung.co.uk
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