The Collaborative International Dictionary of English v.0.48:

Steersman \Steers"man\ (st[=e]rz"man), n.; pl. Steersmen
   (st[=e]rz"men). [Steer a rudder + man: cf. AS. ste['o]rmann.]
   One who steers; the helmsman of a vessel. --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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

Moby Thesaurus II by Grady Ward, 1.0:

42 Moby Thesaurus words for "steersman":
   Gyropilot, agent, automatic pilot, boatheader, boatsteerer,
   cicerone, conductor, conner, courier, cowherd, cox, coxswain,
   docking pilot, dragoman, driver, drover, engineer, functionary,
   goatherd, guide, guidepost, guider, handler, helmsman, herd,
   herdsman, manipulator, mercury, navigator, operant, operative,
   operator, pilot, pointer, river pilot, runner, sailing master,
   shepherd, steerer, tour director, tour guide, wheelman