A small but growing number of wealthy patrons, enamored of the possibilities of undersea exploration, are donating the use of ships, submersibles and other resources to support missions that might otherwise be unaffordable.

Funding pure ocean exploration - going where no person has gone before - has always been hard for researchers. Federal agencies do support exploratory work, but they generally award grants to pursue answers to well-formed questions. This can create a Catch-22, in which scientists don't know which questions to ask until they get into unexplored areas.

Beginning in 2001, the National Oceanic and Atmospheric Administration had an Ocean Exploration program that provided grants for open-ended work, but the program's priorities have shifted toward more limited work aboard the agency's exploration vessel Okeanos Explorer.

Most oceanographers rely on support from the National Science Foundation, but its budget, level at best for several years, has had to deal with rising fuel prices and other costs required to maintain its fleet of research vessels, leaving less available for grants.

The challenge of raising money for sea exploration "is the hardest it's ever been in my career," says Edith Widder, a deep-sea biologist and founder of the Ocean Research and Conservation Association in Fort Pierce, Fla.

Enter the elite benefactors. Hollywood director James Cameron is perhaps the most well known of this group. He donated the Deepsea Challenger, his deep-diving submersible, to the Woods Hole Oceanographic Institution in Massachusetts in March and gave the institute $1 million to help keep the vehicle operational and to support efforts to transfer technologies developed for the sub to other uses.

"I wanted to be sure to fund this enough so that they would have the people and resources to absorb this stuff, describe it and publish it, to have it available," said Cameron. He is also an adviser for Woods Hole's new Center for Marine Robotics, which aims to speed development of advanced ocean technologies through partnerships with private companies in fields such as oil and gas exploration.

Last year in his sub, Cameron did the first solo dive to the deepest spot in the ocean, nearly 36,000 feet deep in the western Pacific.

Oceanographers say the lack of exploration of this and other deep-sea trenches shows the huge potential for discovery, while the lack of vehicles capable of reaching such depths illustrates that in some ways it is more difficult to do so than it is to reach space.

Among the technologies Cameron is transferring to Woods Hole are lightweight cameras built from scratch for the Challenger. The sub's camera equipment and lighting enabled Cameron to capture high-resolution, 3-D images of geologic scenes and deep-dwelling species in the pitch-black depths reached during his dives.

Cameron is not the only person investing in Woods Hole research. Billionaire hedge fund founder Ray Dalio has just donated $5 million to support ocean exploration missions and technology development.

Dalio has also given Woods Hole scientists use of his adventure yacht/research vessel, Alucia, along with his submersibles, scuba support system and other equipment, and other donations to support such work.

A 2012 expedition using Alucia that didn't involve Woods Hole captured the first-ever video of a giant squid in its deep-sea habitat.

Woods Hole's collaboration with Dalio has supported coral reef studies in Micronesia and sperm whale research off New Zealand. The institute's researchers have also been able to test new camera and remotely operated vehicle systems from Alucia.

"One thing that makes this exciting is that (Dalio) is prepared to fund things that might not get funded through traditional sources," says Rob Munier, Woods Hole's vice president for marine facilities and operations.