Spirit Deep by Thomas J. Waite
Approx. 88,790 words.
Published on April 2, 2010.
During a pleasure dive on a rare vacation off the coast of Florida, a renowned treasure hunter and his wife stumble upon the wreck of a sunken Spanish galleon. Though her sinking took place over four hundred years ago, she looks as if she'd just hit bottom after her fateful trip from the surface.
Vast treasures await, but a formidable guardian lurks the depths around his greatest discovery...