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Do you have powerful twin motors at your ankles or a pair of mini-anchors? Do you prefer conventional design or splash out on split-fin technology? The right choice of fin is important to your underwater comfort, especially when there are currents to overcome. John Bantin cracks the whip as five divers put 26 pairs of fins to the speed test...
PETE MCCARTHY IS AN ASTUTE MAN. An aeronautical engineer, he put his mind to developing an improved design for fins. He called it the Nature's Wing.
Instead of producing the fins himself and taking on the established manufacturers, he simply patented his idea and sold the manufacturers licences to use the patent. So, no production problems, no mass-marketing headaches, no distribution difficulties for Pete.
First to buy the idea was the Japanese Apollo company. It made a split-fin from old-fashioned, natural black rubber. It was the first split-fin that I tried and it did very well in our last comparative test of fins, published in Diver in September 1999.
We said then that the Apollo Biofin was heavy, expensive and rather unattractive, yet the performance we measured seemed to be exceptional. At that time we measured the best effort achieved over a number of attempts by the same tethered diver pulling against a spring-balance.
At the time, fin designs were almost evenly divided between those that scooped the water, such as Mares Plana Avantis, and those that flicked it, exemplified by Cressi-sub's Master Frog.
The aquadynamic properties of the split-fin have led some to name it a "propeller-fin" design, and this now forms a third way. Although not a brand that has a great presence in UK dive shops, we have included the latest Apollo natural rubber propeller-fins in this review.
I don't know if our 1999 test had any bearing on Pete McCarthy's ability to sell his idea to other manufacturers of fins, but his Nature's Wing design has certainly been well accepted by US (and Taiwanese) manufacturers. It has sprung up in all sorts of guises since.
The US market is very unlike the tougher European one. Americans want to be able to buy performance off the shelf. They don't take kindly to being told that they are not fit enough or that they have bad technique. It's the philosophy that evolves from the idea that the almighty dollar will buy you anything.
So US fin manufacturers have concentrated on making their products as comfortable as possible.
"Buy our fins and it will seem like you have no fins on you feet at all," they imply. Didn't Hans Christian Anderson write a story about that? Wasn't it something to do with an emperor and a set of new clothes?
All I can say is that some of the examples of split-fins I have been sent to use during the intervening period have disappointed me, and the very many dive guides to whom I have spoken around the world seem to agree. I was equally unimpressed by the genre of pivot-bladed fins launched as a European hi-tech answer to the American-led split-fin challenge.
Pete McCarthy knows my views, but as I said at the beginning, he is an astute man. Instead of instructing his lawyers, he phoned me one evening from the States and set about, in a charming way, trying to convince me that I had got it wrong.
Well,
I am always ready to be proved wrong, so I listened to what he had to
say and planned a new fin comparison test to find out if he could be
right. Pete was all for that, and wanted to do his best to facilitate
matters. Being an engineer, he had designed an underwater speedometer
and sent several examples over for us to use.I contacted every distributor of fins in the UK and told them of Pete McCarthy's challenge. I invited them to send me an example of their best-performing fins, or several different models if they felt they were all contenders. We were sent fins that retailed in a range from £30 to nearly £240. The test divers were unaware of price differences at the time of testing.
If your favourite brand of fin is not represented here, it is because its distributor declined to take part in the contest. If a specific model is missing, it could be because its maker felt that the design was more suited to comfort than performance.
It was telling, for example, that the distributors for HTM, manufacturer of both the Dacor Panther and Mares Volo, chose not to supply an example of either of these high-tech pivot-bladed fins for the test. Could it be that it does not have sufficient confidence in them when it comes to the serious stuff?
So what of the test swimmers, each equipped with a basic scuba set, wetsuit and boots?
We wanted to get a cross-section of results with different diver body types ranging from the genteel to someone a bit more fit.
We
couldn't get a member of the South Korean World Cup team so we settled
for Chris Boardman. He has legs and heart of the type that win Olympic
cycling gold medals, and he still holds the Blue Riband record for the
greatest distance cycled in one hour. Chris has done a lot of comparative
sports-performance research, not unnaturally mainly involving cycling
equipment, and he made an invaluable contribution to the thinking behind
this particular test.Underwater photographer Craig Nelson and Steve Weinman, Managing Editor of Diver, added an experienced element to the team while callow youth came in the form of new diver Stephen Gill. Brute strength was represented by a relatively inexperienced diver but keen ex-club rugby-player, Alex Khachadourian.
There was nothing sinister about the absence of any women on the team - this was driven purely by the practicality of avoiding additional sets of fins in smaller sizes. As it was, the pool-side looked like an aquatic shoe shop during a January sale.
Fins are used by divers in many different ways. However, it's when you find yourself attempting to make headway into a current that you really find out if your fins can deliver what they promised. It's when you have your head down and are going for it that you discover whether you made the best purchasing decision, and this is what our comparison test is about.
So what is the significance of top speed? Well, if you are heading into a half-knot current with a fin with which you can manage one knot in still water, you will make half a knot of headway.
Of course this doesn't take into account factors such as manoeuvrability and control. There are divers who will gladly forego top speed for perceived torque, or simply comfort.
Divers such as underwater photographers, who need to position themselves precisely, might find that a "fast" fin is not what they need at all. Control is important for them most of the time, but there seemed little point in us measuring the speed of a fin when a frog-kick or sculling kick was used, as this would be entering the realms of the purely subjective.
The fit of a fin is a personal thing, but today most fins have a footpocket long enough to encompass most of the foot. Where fins proved uncomfortable, we say so. Most of the fins seemed to have straps and quick-release buckles that were very similar, and we note the exceptions.
The point of using a speedometer to measure the maximum speed achieved is that, once the test diver has accelerated away from rest, he can vary his finning method but still discover what gives a maximum speed reading very quickly.
This is achieved early enough that those of our test divers with lesser stamina did not tire, and results were consistent over the whole period of the test.
The most effective fin-stroke was with legs outstretched and the arc of movement of the fins more or less contained within an area equivalent to the frontal area of the diver - in other words, a fast flutter-kick.
We used a typically shallow swimming pool so that, provided each test diver was below the surface and not scraping the bottom, he was within a fairly restricted depth range. It was simply a matter of swimming along as fast as possible, holding the speedometer out in front and observing the best speed reading obtained. It was not necessary to sustain this top speed over any particular distance, so it never became an aerobic exercise.
We went out of our way to ensure that the comparison test was as even-handed as possible. The spread of results revealed a consistency of style and performance between the different divers that surprised even us. We're confident that it was the different fins used that made the difference in speeds recorded.
Of course, different individuals may get higher or lower speeds with the same fins. To save embarrassment to individual test-team members, we have aggregated the results, but we make no apologies for the results we publish here.