Hands Free Freediving Gear Review : Part I
Posted By Paul Kotik on 6 February 2003
There are a number of good reasons why a person should join hand to nose, but equalizing the middle ear is not one of them. It is awkward, unaesthetic, and decidedly not hydrodynamically efficient. It is a drag. Unfortunately, for the general run of freedivers, squeezing the nostrils shut is what makes equalizing possible. Few can do without the helping hand. Those who can are the envy of all the rest.
Now, to be sure, freedivers willing to forego the luxury of underwater vision have always been able to clip their noses shut and thereby dive hands-free, sans the mask with its dead air space whose pressure has to be equalized during descent by pumping air into it through the schnoz. Can't pump air through a schnoz clamped shut with with an aquatic Vise-GripTM , so clamped nose meant no mask and terrible vision. Conventional goggles were never a solution, insofar as there was no feasible way to get air into them at all.
But now, be of good cheer all you handily handicapped, glottally challenged and pharyngally phrustrated, for science and engineering now offer a couple of ways out. If one is willing to accept and adapt to the trade-offs, technological solutions are reaching a level of maturity which merits consideration.
Fluid goggles have been around for several years, and are now offered commercially by designer Eric Fattah, an engineer and constant ballast world record setter. The concept is quite simple: rather than retaining dead air, which would be subject to intolerable compression after only a few meters' descent, fill the goggles with a non-compressible fluid. But then, the skeptic is quick to ask, if we are going to fill the goggles with fluid, why have goggles at all ?
The answer is vision. LiquivisionTM fluid goggles provide a physical platform for an optical system that, in principle, can correct for the refractive properties of the fluid medium and yield serviceable underwater vision to the human eye. This is accomplished by integrating special optics into the goggles' eyepieces. The trick is in designing the lenses. This is a pretty unusual problem in optical engineering, managing a chain of refraction through two fluids ( the ocean and the fill fluid) and at least two solids ( the goggles and the optical system components) before the light reaches the cornea.
LiquivisionTM fluid goggles have the overall look and feel of ordinary swim goggles until, on closer examination, one notes the lenses mounted on the inside surfaces of the eyepieces.
I first tried them on dry, in my living room, and could not see a thing. The effect was similar to what it might be were the goggles filled with colorless petroleum jelly.
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