How does the one man save himself? What kind of man is he, judging from his clothing and accent?

"The stern had been thrown into the air, and the man (having his hands free, and for all he was encumbered with a frieze overcoat that came below his knees) had leaped up and caught hold of the brig's bowsprit."

The Captain implied to the man that he could tell from his French coat that he was a Jacobite, and thus not loyal to King George.