The Collaborative International Dictionary of English v.0.48:

Hatchway \Hatch"way`\ (-w[=a]`), n.
   A square or oblong opening in a deck or floor, affording
   passage from one deck or story to another; the entrance to a
   cellar.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hatchway
    n 1: an entrance equipped with a hatch; especially a passageway
         between decks of a ship [syn: hatchway, opening,
         scuttle]