Real Life History
This information is not to be used in-game, but is instead to help you, the player, understand what your character is sailing
"The longboat should not be confused with a Longship; nor with a narrow boat.
In the days of sailing ships, a vessel would carry several boats for various uses. One would be a longboat, an open, primarily rowing, boat with eight or ten oarsmen, two per thwart."
(Source & full article: Wikipedia)