Virgin Group founder Richard Branson, known for such exploits as trying to balloon around the world, said on Tuesday he planned to explore the deepest parts of the world's oceans with a jet-like submarine.
The 18-foot (5-1/2 meter) vessel is capable of descents of more than 36,000 feet below the surface, said Branson at a news conference in Newport Beach, California.
His project, called Virgin Oceanic, will undertake five dives over two years. The first is set for later this year, when the team plans to explore the Pacific Ocean's Mariana Trench at a depth near 36,000 feet.
Branson plans to pilot a second dive himself, into the Puerto Rico Trench in the Atlantic Ocean.
Other areas to be explored are the Molloy Deep in the Arctic Ocean, South Sandwich Trench in the Southern Ocean and Diamantina in the Indian Ocean.
"There is just so much to explore, so much to discover," Branson told reporters. "We are going to obviously come across some fascinating creatures and learn some fascinating things that will hopefully be useful for mankind."
Branson said he expects the project to cost less than $10 million.
Branson said Virgin Oceanic could one day take passengers on deep sea dives, just as his Virgin Galactic project may one day take wealthy passengers on suborbital spaceflights.
Branson launched the Virgin chain of record stores in the 1970s, and his business holdings have grown to include a music recording label and Virgin Atlantic Airlines.
He has used his fortune to fund such efforts as trying to circumnavigate the globe in a balloon and set sailing records.
Last month, a suborbital spaceship owned by Branson's Virgin Galactic was attached to a carrier aircraft on a three-hour flight over California's Mojave Desert.
Its test flights are scheduled through 2011 with commercial operations targeted for 2012.
The company has collected deposits and fares from more than 330 aspiring amateur astronauts, who will each be charged $200,000 to experience suborbital spaceflight.