The Hunley can be crewed by three people but only sleeps two. The maximum attainable depth of the Hunley, a figure arrived at after extensive testing was just under 25 miles, a depth considerably greater than that found on most Class M worlds but that is known to exist in certain areas. Theoretically, the absolute maximum attainable depth is 30 miles, although critical structural stresses would make this an exceptionally risky option that would, quite likely, result in the shuttle's implosion. The vessel's deflector dish can be covered by a retractable panel to reduce drag levels while submerged if preferred.