Complex sentence: In 2010 Mearns announced a new plan to search for the wreck: the plan is sponsored by the National Geographic Society but is subject to finding sponsorship for the balance of the U.S. $10 million estimated cost.
Split into simpler sentences: In 2010 Mearns announced a new plan to search for the wreck. The plan is sponsored by the National Geographic Society but is subject to finding sponsorship for the balance of the U.S. $10 million estimated cost.