Cream shortening in a large mixing bowl; gradually add sugar, beating well. Add egg, water, and vanilla, beating well.
Sift together flour, soda, and salt in a small mixing bowl; add to creamed mixture, stirring until well blended. Add oats, mixing well.
Drop batter by heaping teaspoonfuls 3 inches apart onto lightly greased cookie sheets. Bake at 350° for 12 to 15 minutes or until lightly browned. Remove from cookie sheets, and let cool completely on wire racks.