The Undertakers shall lay down Buoys for the Guidance of Vessels in such Situations within the Limits of the Harbour, Dock, or Pier, and of such Character, as shall from Time to Time be directed by the Corporation of Trinity House, Deptford Strond, the Corporation for preserving and improving the Port of Dublin, or the Commissioners of the Northern Lights respectively, according as the Harbour, Dock, or Pier is situated in England, Ireland, or Scotland.