A coner is someone who works in the
forward part of a
submarine, thusly named for the shape of this part of the ship. Coners, or cones, as they are often called, are lower on the
echelon of submarine life, than their nuclear brethren, who work in the engine room, which is in the aft part of the ship. These other people are referred to as "nuc's", or "
nukes", depending on how you spell it.
A submarine might be split up into as many as three sections. The Engine Room, Missile Compartment, and Forward Compartment. Some people that work in the missile compartment claim not to be cones, but just 'tweeners (y'know, because they are in between), but their coneness betrays them. A cone is simply just not a nuke. But that isn't held against them (too much). They perform useful functions, like steering the ship, firing torpedoes, listening to sonar, making food (which definately is held against them, and pumping sanitary tanks (for which the nukes are most grateful).