Both boats were packed with passengers. Both struck fixed channel markers at high speed. Both collisions left one person dead and others injured. And both were investigated by Florida Fish and Wildlife Conservation Commission officers. Two shattering boat crashes, more than a year and 100 miles apart in South Florida, share compelling similarities. But the resulting investigations produced dramatically different criminal charges. A Key West boat mechanic named Daniel Ross, at the wheel in anighttime collision in October that killed a 46-year-old woman, now faces a homicide charge that could pu…