Underway to Menorca beneath a sunny sky with a twenty knot following wind, the sailing was marvelous and O'Brian was delighted. I introduced him to the helm, but he seemed to have no feeling for the wind and the course, and frequently I had to intervene to prevent a full standing gybe. I began to suspect that his autobiographical references to his months at sea as a youth were fanciful. He had no idea of the limitations of even a big yacht like Andromeda in terms of the handling and actual distance we could cover in a day. However, he and Mary adapted quickly to the yacht with no trace of seasickness. (source)
O'Brian worked on his novel The Yellow Admiral while aboard, as well...
Every afternoon between two and five, Patrick retired to my on-board office to work on his novel The Yellow Admiral, then in progress. He borrowed the yacht's charts of France, particularly the area around Brest, to incorporate detail of the blockade of Brest which is featured in that book. Very much to Mary's surprise he showed me each day's progress. She said that he had never shared his work with anyone before completion. Later, Patrick sent me the original manuscript for this volume which I still keep aboard and which I treasure.(source)
Kind of a neat story that gives you a sense of what O'Brian was like. The fact that this persona was an invention of the author (real name, Patrick Russ), adds another layer of meaning to the whole "Patrick O'Brian" phenomenon.