A Tide in Time: The Log of Matthew Roving, book one

A Tide in Time follows the misfortunes of Matthew and Abby Roving, siblings plunged into double lives as modern teens and accidental secret agents at the heart of the American Revolution. The trouble begins when Matthew stumbles on an antique ship's logbook that functions like a time portal. Soon the 12 year old Matthew is solo-sailing a Death Ship, escaping from murderous mutineers, and managing the affairs of future national heroes like John Paul Jones and Ben Franklin, helping them to keep their focus on the Revolution. But every time he's in the past, his past self is taking his place in the present--creating endless scenes of confusion. As well throughout the story his older sister, Abby, must deal with the mess Matthew leaves behind him every time he makes a jump from 1772 to the modern era. Framing the story is Matthew and Abby's quest to save their naval captain father from British agent Wydontia Gaway, a sinister spinster with chameleon-like qualities, while ensuring the American Revolution starts on time, To be continued in Books Two through Five.