The Collaborative International Dictionary of English v.0.48:

Top-hamper \Top"-ham`per\, n. (Naut.)
   The upper rigging, spars, etc., of a ship. [Written also top
   hamper.]
   [1913 Webster]

         All the ships of the fleet . . . were so encumbered
         with tophamper, so overweighted in proportion to their
         draught of water, that they could bear but little
         canvas, even with smooth seas and light and favorable
         winds.                                   --Motley.
   [1913 Webster]