Source : Webster's Revised Unabridged Dictionary (1913)

Scull \Scull\, v. t. [imp. & p. p. {Sculled}; p. pr. & vb. n.
   {Sculling}.] (Naut.)
   To impel (a boat) with a pair of sculls, or with a single
   scull or oar worked over the stern obliquely from side to
   side.

Source : WordNet®

sculling
     n : rowing by a single oarsman in a racing shell