Originally, the standard complement of each submarine was six officers and thirty-six sailors, with facilities to carry an additional twelve personnel (usually trainees). This number was minimised by the RAN during design, which insisted that functions be automated where possible; the RAN also requiring that each sailor have his own rack and did not need to 'hot bunk'. It was originally intended that multiple ship's companies be established per submarine, and that these be rotated to maximise the submarines' time at sea without adversely affecting personnel, but difficulties in maintaining submariner numbers made this plan unworkable. Enlisted submariners are accommodated in six-bunk cabins.