Fish swam over my head and a landscape of rocks, trees and debris appeared between my feet. In the depths I saw the roots of a Jefferson pine some 2,000 years old.

"Welcome to my office," Capt. Scott Cassell said as he used a joystick to guide the helicopter-like Seamagine submersible ever deeper into Fallen Leaf Lake, not far from Lake Tahoe in northern California.

Seventy-one percent of the Earth's surface is water, and the realms below it offer enormous possibilities for exploration, recreation and education. Yet those depths remain inaccessible to most people. A growing number of explorers and entrepreneurs hope to change that with personal submersibles, an emerging type of watercraft that carry two or three people and fly through our underwater world.

Three companies have shown their craft in California, promising a new era of underwater exploration. Hawkes Ocean Technologies unveiled its latest winged sub and is offering "flights" in Monterey Bay this month. Super Aviator Systems and Seamagine recently demonstrated their watercraft in Lake Tahoe.

These companies push submersibles in a new direction. Most submersibles work like hot air balloons, diving and rising or moving forward and back. Persubs move more like airplanes – or, in the case of the Seamagine, a helicopter. They bring the dynamics of flight to the sea. The technologies could open new avenues of discovery and change how we interact with our endangered seas and lakes.

"A new transport technology always gives new access, and with access comes understanding,” said William Koehan, president of SeaMagine and chairman of the Manned Underwater Vehicle committee for the Marine Technology Society. "Once you understand, you can care. We need a human connection to the ocean."

Persubs offer the portability of a ski boat, while diving deeper and staying submerged longer than scuba divers. Passengers sit in a pressurized cabin, allowing them to focus on the wonders around them instead of things like decompression rates. Persubs also are cheaper than conventional submarines and offer greater maneuverability. They're electric and relatively silent, allowing you to get unusually close to marine life.

Like airplanes, persubs require training, careful maintenance and, depending upon the country, different levels of registration and insurance. The companies selling the craft offer varying levels of support navigating these issues. Their vessels cost between $1.3 million and $2.19 million, but the companies believe costs will come down as production ramps up.

Are persubs the ultimate yachting accessory? A tool for filmmakers, surveyors and scientists? A vehicle for poets and politicians who will change our view of, and policies regarding, the ocean?

Recent activities provide some clues.

The Super Aviator exploring Lake Tahoe in May. Apollo 8 astronaut Bill Anders was among those who got a ride, and he said the craft is fun to fly and "opens all kinds of possibilities for underwater fun and observation."

Photo: Stephen FrinkSub Aviator Systems Soars

The 22-foot long, white-winged Super Aviator submersible from Sub Aviator Systems looked a bit like a jet as it cruised the depths of Lake Tahoe last spring. Record-setting submariner Don Walsh and Apollo 8 astronaut Bill Anders were among the luminaries enjoying the "flights." Anders said the craft is "both fun to fly and opens all kinds of possibilities to underwater fun and observation."

Scientists from the Monterey Research Institute and Scripps Oceanography also spent time in it. Jim Delgado, president and CEO of the Institute of Underwater Archeology, was impressed enough to consider using it in the Bikini Atoll.

"Envision how spectacular it would be, as well as symbolic, to also land and take off with a Super Aviator from the sunken flight deck of the carrier USS Saratoga, which rests in 180 feet of water," he said.

Super Aviator pilots John Jo Lewis and Capt. Alfred McLaren met at the world’s first underwater flight school, which inventor Graham Hawkes and his wife Karen launched in the Bahamas in 2003. I was there, too, for National Geographic Television, and after soaring undersea I wondered how long it might be before underwater flight caught on.

The Super Aviator from Sub Aviator Systems on shore before deployment in Lake Tahoe in May. The two-person submersible is 22 feet long and was designed with help from renowned submersible designer and engineer Dr. Phil Nuytten.

Photo: Alfred McLarenSix years later, Lewis, who is also managing director of SAS, and McLaren believe its time has come. They've worked with Dr. Phil Nuytten, the renowned submersible designer and pilot known for his Deep Worker submersibles. Together they changed the buoyancy of the aviator to make it neutral, something they say makes the safer and easier to control. Without the tendency to ascend when moving at slow speeds, the pilot can creep along and even hover, which McLaren said is great for observing marine life.

That's exactly what the craft will do in February, McLaren said, when researchers use it to study humpback whales off the coast of Maui. McLaren hopes to use the craft to search the continental shelves for remnants of pre-Columbian explorers to the Americas.

SAS is eager to build its first Super OrcaSubs, which will incorporate the improvements developed with Nuytten to meet the safety requirements of insurer Lloyd's of London. SAS says the craft will be able to cover 20 miles a day and dive to depths of 2,000 feet. The pilot can control movement on five axes – pitch, roll, yaw, lateral and vertical – using fly-by-wire controls. A loaded Super Orca will cost $2.19 million, a price that includes training for two pilots and a crewmember.

The Deep Flight Super Falcon from Hawkes Ocean Technologies explores the sea.

Photo: Graham WaltersThe Hawkes & The Falcons

Hawkes Ocean Technologies is known for innovating remote and manned underwater exploration vehicles. In May, the company unveiled the newest version of its personal submersible in San Francisco. Graham Hawkes said the Deep Flight Super Falcon represents his 20-year pursuit to bring flight to the sea just as the Wright brothers brought it to the sky. The goal, he said, was to create a vessel that moves like a dolphin or a shark, not a crab, and free it from the cumbersome infrastructure required to use the Mir and Alvin submersibles.

His first winged watercraft, Deep Flight One, carried one person. It was a breakthrough when it was launched in 1996. His second, Deep Flight Aviator, carried two people and proved itself in the first underwater flying school in the Bahamas six years ago. I had the opportunity to "fly" in it with Hawkes around shipwrecks.

But Hawkes aspired to greater depths and spent years working on Deep Flight Challenger, a solo vessel commissioned by adventurer Steve Fossett. Fosset wanted to set records exploring the Marianas Trench, which at more than 36,000 feet is the deepest point in the sea. Fossett died before that could happen, but the design work contributed to Super Falcon.

The first Super Falcon that Hawkes built went to Tom Perkins, who put it aboard his mega-yacht, the Maltese Falcon. Chris Carter, the yacht's captain, says the submersible has made more than 50 dives and moves through the water like a jet through the sky.

"We have been flying with giant manta rays, a pod of dolphin 30 strong, and all sorts of sharks," he said, adding that it seems the craft attracts marine life. "It’s just incredible!"

Technicians at Chase Boats work on the Deep Flight Super Falcon hull.

Photo: Hawkes Ocean TechnologiesThe second Super Falcon went to the Monterey Bay National Marine Sanctuary after its unveiling in San Francisco. It is being used in an invitation-only flight school and a "VIP of the Seas" project with the National Oceanic and Atmospheric Administration.

"We are hoping this program will raise awareness of the importance of marine sanctuaries when people can experience the underwater part of the ocean for the first time," said William Douros, West Coast regional director of the agency's National Marine Sanctuary Program. "Any time we see innovation that might help the seas, we are curious and want to help."

Todd Lueders, head of the Community Foundation for Monterey County, was among those who took a flight. "It was the opposite of the images of Jacques Cousteau sinking heavy in a bathysphere," he said. "I see incredible eye-opening potential for opinion leaders and scientists."

The Super Falcon uses fly-by-wire controls. It cruises at 2 to 6 knots and can dive to 1,000 feet. The Hawkes hope to begin producing it soon and say it will cost about $1.5 million, which includes the training to operate it.

Seamagine President Will Kohnen uses external controls to pilot the Seamobile submersible to a boat dock in Fallen Leaf Lake in Northern California before picking up passengers.

Photo: Lisa TE SonneSeamagine Hydrospace

When it comes to persubs, no one beats William Kohnen and Seamagine Hydrospace for time in the water. The company claims to have made more than 10,000 dives around the world since 1995 and is currently building crafts No. 8 and 9. But Kohnen took a different approach to underwater flight.

"Back in 1991-92, I had the idea of an underwater helicopter with a forward cockpit for clearer vision in all directions," he said. "To achieve balance for the submersible, we pushed the center of gravity back and used a tail for lift."

Seamagine builds two models, the two-person Pearl and the three-person Triumph. It also is ready to begin taking orders for the Seamobile, which dives to 500 feet and costs $1.3 million. It can be designed to reach depths as great as 3,000 feet, but you'll pay more for a vehicle that will go that deep. The sticker price includes American Bureau of Shipping classification and flight training.

"It's a perfect device to explore wrecks," said archaeologist George Bass, who first used a Seamagine sub named Carolyn in 2000 in Turkey after considering several other submersibles.

The Seamobile looks more like a Volkswagen than a Ferrari, and with a top speed of just 2 knots it won't win any races. But its adherents will tell you the helicopter design is superior to winged craft because it is roomier with better hovering capability and superior visibility since you sit in an acrylic sphere. You can also get in and out of it faster because it is taller and more stable on the surface than winged submersibles, which must be hauled out of the water to change passengers.

Much like the world they are designed to explore, persubs are a new frontier. They are not regulated like aircraft, nor are their operators licensed like pilots. Regulations, registration and insurance vary by country. Some worry that increased oversight would impede innovation and drive up costs. But others worry builders may not effectively self-regulate to ensure safety, something that could damage the emerging field.

As the committee chairman for Manned Underwater Vehicles of Marine Technology Society, Kohnen hosts an annual discussion of such issues. He wants to ensure the field advances safely and thoughtfully and plans to establish his own benchmarks in future dives off the California coast.

He also dispatched a Seamobile to the month-long Tahoe Expedition in May. My pilot, Capt. Cassell, was there to test the vehicle for possible use in his nonprofit Undersea Voyager project, which aims to circumnavigate the world underwater. Several novices explored the lake, including a group of teens interested in science and exploration. Many of the scientists and adventurers who took dives shared their experiences with a packed audience at the local community college.

We were well into my dive and about 110 feet beneath the surface when Cassell said, "I have a surprise for you now." He brought the Seamobile up like a helicopter to within inches of billowy algae growing on the trunks of ancient trees. Soon we spotted small transparent spheres, which scientists on previous dives suggested might be protists, the fourth phylum of the living kingdom. They aren't animals, or plants, or algae but have characteristics of each. We are still learning about them.

Like protists, personal submersibles occupy their own category. They are a tool, a toy, a business and a portal waiting to be better understood and used.