40 Fathom Grotto

World-famous 40 Fathom Grotto is a naturally formed sinkhole located in the heart of north-central Florida’s thoroughbred racing country. It is the only place in the eastern United States where you can train, dive or play in depths of up to 200 feet or more and still: Remain completely in open water, if you choose. Dive year round in calm, fresh water. Be largely unaffected by wind, waves, tides, currents. It’s no wonder then that dive educators from around the world consider the Grotto to be the Ultimate Training Facility. Grotto Geology Geologically, the Grotto is what is known as an in-line sinkhole. Sinkholes form when the earth and rock above an underground river become weakened by the flow of water underneath. Eventually, this earth and rock collapses. Much of this material is carried away by the current; that which remains forms what is known as a debris cone, which the river now flows up and over. Sinkholes seldom have perfectly straight walls (the Grotto is no exception). The Grotto’s sides slope outward — often at a substantial angle — resulting in a diameter at the base which is several times greater than it is at the surface. Divers need to bear in mind that, even though they may appear to be in open water, ascents must be made cautiously — lest you clobber yourself on an overhanging ledge. There sure has been a lot of activity at the 40 Fathom Grotto since it's operation was taken over by the Commercial Diving Academy. We started by acquiring the surrounding land, which increased the overall facility to 7 acres. Once that was accomplished, the demolition and construction began. It has been going on in earnest for over 6 months now and things have really shaped up. Renovations are pretty well complete but the expansion continues. However, the expansion activities in no way hinder with diving operations. HISTORY It’s the early 1950s. Scuba diving is in its infancy. Word spreads slowly throughout the tiny Florida diving community of a mysterious hole in the ground, northwest of Ocala, known locally as Zuber Sink. (At the time, Zuber was the closest town of any consequence; ironically, it is eight miles away, on the opposite side of I-75 from the Grotto.) Early exploration of Zuber Sink are limited by the primitive nature of the scuba equipment available at the time: Double-hose regulators that are almost impossible to breathe from past 40 m/130 ft; no pressure gauges or BCs; small cylinders; ill-fitting wet suits. Eventually, though, divers establish a maximum depth for the sinkhole: 73 meters or an even 240 feet. It is this discovery that gives this natural wonder the name that will stick: 40 Fathom Grotto.