Carbon Based Life Forms Call Home
Posted By Paul Kotik on 21 July 2003
I conducted a semi-scientific test of the efficiency differences between C4 carbon 40's and my trusty plastic blades. The test was deliberately designed to stack the deck against finding any difference - it was based on dynamic apnea swimming in a pool. Two experienced local freedivers were tasked with swimming repeat 25 meter underwater lengths. Lots of them. The divers were asked to make a good-faith effort to maintain constant technique and water speed. Blades were swapped in and out.
The results ? One diver experienced a consistent 10% gain in efficiency with the C4 blades, as reflected in fewer kick cycles per 25 meter length. The other diver experienced a similar gain, but only for about half of the trials. However, this guy was showing shorter lap times for the trials in which his kick cycle count was the same as with the plastic fins. He was moving faster with the C4's, and, when he was moving faster, he was doing that body twisting thing I'd noticed on my first dive with C4's. He had not adjusted to the greater through-put of the C4's.
I was pretty impressed by this finding. 10% may not seem like a lot, but given that the measuring method was deliberately insensitive, it speaks volumes. There is no doubt about the superior efficiency of carbon blades as propulsion devices for the freediver. Efficiency is what freediving is all about. Maximizing the potential efficiency gains offered by carbon fiber blades does, in my opinion, require some attention to optimizing technique, but this is something we should all be doing anyway. As a consumer, the only question you face is whether carbon blades are worth the considerably greater expense over regular plastic.
Carbon fiber does have some well-known disadvantages. It is unspeakably strong in some ways (e.g., tensile strength) but surprisingly fragile in others. When carbon fiber masts began to replace aluminum in the windsurfing world, we quickly learned that these fabulous new spars did not take well to being chucked from the roof rack to the parking lot surface. Ultraviolet light is not friendly to carbon fiber, either. Things that scratch and bang are best avoided. That said, I have many friends and colleagues who pack their C4's in soft bags and submit them to the gentle hands of airline baggage handlers on a weekly basis, with no known casualties to date.
I, personally, have to have carbon fiber blades. My C4 40's are an essential tool in my freediving kit. They quickly and easily mount and dismount in the footpockets that came with my plastic fins. I use the C4's for most down-and-up the line freediving, and swap in the plastic blades for the rough stuff on the reef, the wreck or for shore dives involving surfy or rocky entry/exit and relatively shallow diving.
C4 blades, while still costly, are becoming easier to acquire. Contact Marco at info@c4carbon.com for direct orders or for a distributor in your corner of the world. C4 also builds blades with higher carbon fiber content ( even better, even more fragile, even more expensive) than the 40's, and is applying carbon fiber technology to spear guns as well
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