Adams sailed for France aboard the Continental Navy frigate Boston on February 15, 1778. The trip through winter storms was treacherous, with lightning injuring 19 sailors and killing one. Adams’ ship was then pursued by but successfully evaded several British frigates in the mid-Atlantic. Toward the coast of Spain, Adams himself took up arms to help capture a heavily armed British merchantman ship, the Martha. Later, a cannon malfunction killed one and injured five more of Adams’ crew before the ship finally arrived in France.
Sources: http://en.wikipedia.org/wiki/John_Adams