According to the link you sent:

[b]"Originally, on board sailing ships the boatswain was in charge of a ship's anchors, cordage, colours, deck crew and the ship's boats. The boatswain would also be in charge of the rigging while the ship was in dock."[/b]

Thus, generally a boatswain or bo'sun, is in charge of the deck and cargo areas while the Master of Sail is in charge of the sails above. I rather suspect that the pair work in concert since they share the same common pool of hands.