This means the person has passed the Skipper Large Powerboat Course and logged 100 days of time into their logbook with at least 50% as Master of the vessel on a vessel greater than 20 ft and at least 50% on a vessel greater than 26 feet.
To gain the added designation of "with verified practical competency," this means the person has been assessed by a NauticEd American National Standards Instructor and graded as a competent large powerboat skipper.