The Collaborative International Dictionary of English v.0.48:

Helmsman \Helms"man\, n.; pl. Helmsmen.
   The man at the helm; a steersman.
   [1913 Webster]

WordNet (r) 3.0 (2006):

helmsman
    n 1: the person who steers a ship [syn: helmsman, steersman,
         steerer]

Moby Thesaurus II by Grady Ward, 1.0:

31 Moby Thesaurus words for "helmsman":
   Gyropilot, automatic pilot, boatheader, boatsteerer, cicerone,
   conner, courier, cowherd, cox, coxswain, docking pilot, dragoman,
   drover, goatherd, guide, guidepost, guider, herd, herdsman,
   mercury, navigator, pilot, pointer, river pilot, sailing master,
   shepherd, steerer, steersman, tour director, tour guide,
   wheelman